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Hwang G, Kim D. Transport and retention of positively charged zinc oxide nanoparticles in saturated porous media: Effects of metal oxides and clays. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 351:124007. [PMID: 38677461 DOI: 10.1016/j.envpol.2024.124007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/27/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024]
Abstract
The effects of metal oxides and clays on the transport of zinc oxide nanoparticles (ZnO-NPs) in saturated porous media were investigated under different ionic strength (IS) conditions. We studied the transport and retention behavior of ZnO-NPs for different types of porous media (untreated, acid treated, and acid-salt treated sand). The selected untreated sand was used as a representative sand, coated with both metal oxide and clay. The acid treated and acid-salt-treated sands were used and compared to investigate the effects of clays on the surface of the sand. In addition, the effects of clay particles in bulk solutions on the mobility and retention of ZnO-NPs were observed using bentonite as a representative clay particle. We found that the increased mobility of positively charged ZnO-NPs can be attributed to increasing charge heterogeneity of silica sand with metal oxides (mainly, iron oxide) and clays in untreated sand. No breakthrough of ZnO-NP was observed for acid-treated (presence of clays and absence of metal oxides) and acid-salt-treated sand (absence of both metal oxide and clays). Most of the injected ZnO-NPs were deposited on the surface of the sand near the column inlet. The transport of bentonite-facilitated ZnO-NPs was improved at the lowest IS (0.1 mM) (∼20%), whereas there was no difference in the mobility of ZnO-NPs at high IS solutions (1 mM and 10 mM). In particular, the breakthrough amount improved with increasing bentonite concentration. Classical Derjaguin-Landau-Verwey-Overbeek interactions help explain observed interactions between ZnO-NPs and sand as well as bentonite and sand.
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Affiliation(s)
- Gukhwa Hwang
- Department of Mineral Resources and Energy Engineering, Jeonbuk National University, Jeonju, Jeonbuk-do, 54896, Republic of Korea; Research Institute for Energy and Mineral Resources Development, Jeonbuk National University, Jeonju, Jeonbuk-do, 54896, Republic of Korea.
| | - Donghyun Kim
- Resources Utilization Division, Korea Institute of Geoscience & Mineral Resources, Daejeon, 34132, Republic of Korea
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2
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Nguyen VT, Pham NH, Papavassiliou DV. Aggregation of nanoparticles and morphology of aggregates in porous media with computations. J Colloid Interface Sci 2023; 650:381-395. [PMID: 37418889 DOI: 10.1016/j.jcis.2023.06.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/30/2023] [Accepted: 06/08/2023] [Indexed: 07/09/2023]
Abstract
HYPOTHESIS The main hypothesis is that the aggregation process for nanoparticles (NPs) propagating in porous media is affected by the structure of the flow field as well as by the properties of the primary NPs. If this were true, then the aggregation could be predicted and controlled. However, to obtain reliable results from computations, one needs to account for the interactions between the NPs as well as the details of the fluid velocity, thus making advances over prior efforts that either ignored the aggregation of NPs, or used probabilistic methods to model aggregation. EXPERIMENTS Computational experiments were conducted using the lattice Boltzmann method in conjunction with Lagrangian particle tracking (LPT). The LPT accounted for the physicochemical interaction forces among NPs. Computationally obtained aggregation kinetics and fractal dimensions of Cerium oxide (CeO2) particles, suspended in potassium chloride (KCl) solutions with different concentration, were verified against experimental results. The model was then employed to investigate the effects of ionic strength, fluid velocity, and particle size on the aggregation kinetics and the aggregate morphology, as NPs propagated in the pore space between randomly packed spheres. FINDINGS The aim of this study was to develop a computational model to simulate the aggregation of NPs and obtain the morphology of aggregates in confined geometries, based on the physics of NP interactions and the flow field. The most important factor that impacted both the aggregation process and the aggregate structure was found to be the concentration of the electrolyte. The pore velocity influenced the aggregation kinetics and the NP fractal dimension, especially in diffusion-limited aggregation. The primary particle size affected the diffusion-limited aggregation kinetics and the fractal dimension of reaction-limited aggregates noticeably.
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Affiliation(s)
- Vi T Nguyen
- School of Chemical Biological and Materials Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Ngoc H Pham
- School of Chemical Biological and Materials Engineering, The University of Oklahoma, Norman, OK 73019, USA
| | - Dimitrios V Papavassiliou
- School of Chemical Biological and Materials Engineering, The University of Oklahoma, Norman, OK 73019, USA.
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3
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Tao H, Yang L, Qi Y, Chen Y, Yu D, Zhou L, Lin T, Xu H, Song J. Deposition of polystyrene microplastics on bare or biofilm-coated silica analysed via QCM-D. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157661. [PMID: 35907535 DOI: 10.1016/j.scitotenv.2022.157661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
The mobility of microplastics (MPs) in aqueous media is closely related to their environmental risk. The naturally occurring silica substrate surface in the aquatic environment is easily colonized by microorganisms and forms a biofilm, which may affect the migration and distribution of MPs. Herein, a typical MP, polystyrene (PS), and Pseudomonas fluorescens (P. fluorescens) biofilms were selected to study the deposition and release of pristine or ultraviolet (UV)-aged PS MPs on silica and biofilms under different ionic strengths using a quartz crystal microbalance dissipation (QCM-D) system. Statistical analyses of the deposition experiments revealed a significant impact of P. fluorescens biofilms on deposition (p = 0.0042). The deposition rate of weathered MPs on the biofilms was 4.0 ± 0.1 to 16.3 ± 0.6 times that on silica. A release experiment revealed that the biofilm reduced the release fraction (fr) of weathered MPs by 34.5 ± 0.3 % compared to bare silica. In addition, the UV-ageing treatment reduced the deposition mass of MPs on the surface of silica by 27.6 ± 0.21 % compared to pristine microspheres. The analysis of the deposition mechanism revealed that the promotion and inhibition of biofilm or UV-ageing treatment on the deposition of microspheres could be attributed to the non-Derjaguin-Landau-Verwey-Overbeek (DLVO) force and the decreased electrostatic repulsion or the increased hydration repulsion, respectively.
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Affiliation(s)
- Hui Tao
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China.
| | - Lan Yang
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Yiting Qi
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Yiyang Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Duo Yu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Lingqin Zhou
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Hang Xu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China
| | - Junlong Song
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Joint International Research Lab of Lignocellulosic Functional Materials, Nanjing Forestry University, Nanjing 210037, China
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Pulido-Reyes G, Magherini L, Bianco C, Sethi R, von Gunten U, Kaegi R, Mitrano DM. Nanoplastics removal during drinking water treatment: Laboratory- and pilot-scale experiments and modeling. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129011. [PMID: 35643007 DOI: 10.1016/j.jhazmat.2022.129011] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/08/2022] [Accepted: 04/23/2022] [Indexed: 06/15/2023]
Abstract
Microplastics detected in potable water sources and tap water have led to concerns about the efficacy of current drinking water treatment processes to remove these contaminants. It is hypothesized that drinking water resources contain nanoplastics (NPs), but the detection of NPs is challenging. We, therefore, used palladium (Pd)-labeled NPs to investigate the behavior and removal of NPs during conventional drinking water treatment processes including ozonation, sand and activated carbon filtration. Ozone doses typically applied in drinking water treatment plants (DWTPs) hardly affect the NPs transport in the subsequent filtration systems. Amongst the different filtration media, NPs particles were most efficiently retained when aged (i.e. biofilm coated) sand was used with good agreements between laboratory and pilot scale systems. The removal of NPs through multiple filtration steps in a municipal full-scale DWTP was simulated using the MNMs software code. Removal efficiencies exceeding 3-log units were modeled for a combination of three consecutive filtration steps (rapid sand filtration, activated carbon filtration and slow sand filtration with 0.4-, 0.2- and 3.0-log-removal, respectively). According to the results from the model, the removal of NPs during slow sand filtration dominated the overall NPs removal which is also supported by the laboratory-scale and pilot-scale data. The results from this study can be used to estimate the NPs removal efficiency of typical DWTPs with similar water treatment chains.
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Affiliation(s)
- Gerardo Pulido-Reyes
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland.
| | - Leonardo Magherini
- Department of Environmental, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy
| | - Carlo Bianco
- Department of Environmental, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy
| | - Rajandrea Sethi
- Department of Environmental, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland; School of Architecture, Civil, and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland; Environmental Systems Science Department, ETH Zurich, 8092, Zurich, Switzerland
| | - Ralf Kaegi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland.
| | - Denise M Mitrano
- Environmental Systems Science Department, ETH Zurich, 8092, Zurich, Switzerland
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Liu G, Li H, Liu Y, Jin R, Zhou J, Ren Z, Wang Z, Yan C. Extracellular electron transfer influences the transport and retention of ferrihydrite nanoparticles in quartz sand coated with Shewanella oneidensis biofilm. JOURNAL OF HAZARDOUS MATERIALS 2021; 417:126023. [PMID: 33992002 DOI: 10.1016/j.jhazmat.2021.126023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
Microbial biofilm has been found to impact the mobility of nanoparticles in saturated porous media by altering physicochemical properties of collector surface. However, little is known about the influence of biofilm's biological activity on nanoparticle transport and retention. Here, the transport of ferrihydrite nanoparticles (FhNPs) was studied in quartz sands coated with biofilm of Shewanella oneidensis MR-1 that is capable of reducing Fe(III) through extracellular electron transfer (EET). It was found that MR-1 biofilm coating enhanced FhNPs' deposition under different pH/ionic strength conditions and humic acid concentrations. More importantly, when the influent electron donor (glucose) concentration was increased to promote biofilm's EET activity, the breakthrough of FhNPs in biofilm-coated sands was inhibited. A lack of continuous and stable supply of electron donor, on the contrary, led to remobilization and release of the originally retained FhNPs. Column experiments with biofilm of EET-deficient MR-1 mutants (ΔomcA/ΔmtrC and ΔcymA) further indicated that the impairment of EET activity decreased the retention of FhNPs. It is proposed that the effective surface binding and adhesion of FhNPs that is required by direct EET cannot be neglected when evaluating the transport of FhNPs in sands coated with electroactive biofilm.
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Affiliation(s)
- Guangfei Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China; Key Laboratory of Eco-restoration of Regional Contaminated Environment, Shenyang University, Shenyang 110000, China.
| | - Hanyi Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yang Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Ruofei Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhen Ren
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Chen Yan
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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He L, Rong H, Li M, Zhang M, Liu S, Yang M, Tong M. Bacteria have different effects on the transport behaviors of positively and negatively charged microplastics in porous media. JOURNAL OF HAZARDOUS MATERIALS 2021; 415:125550. [PMID: 33740724 DOI: 10.1016/j.jhazmat.2021.125550] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Bacteria, biological colloids with wide presence in natural environments, would interact with plastic particles (emerging colloids with great concern recently) and thus would influence the fate and distribution of plastics in environment. In present research, the impacts of bacteria (both Gram (-) E. coli and Gram (+) B. subtilis) on the transport/deposition of model microplastics (MPs) in porous media were examined in NaCl salt solutions (5 and 25 mM, pH = 6). Both negative carboxylate-modified MPs (CMPs) and positive amine-modified MPs (AMPs) were concerned. We found that under both solution conditions, the presence of both types of bacteria decreased CMPs transport and enhanced retention of CMPs in sand columns. In contrast, the presence of bacteria (regardless of cell type) yet increased AMPs transport and decreased their deposition in sand columns under both ionic strength conditions. The mechanisms leading to the altered transport of CMPs and AMPs by bacteria were different. The formation of larger sized CMPs-bacteria clusters and the extra deposition sites resulted from bacteria adsorbed on quartz sand contributed to the decreased CMPs transport and enhanced their deposition in sand columns. Whereas, the formation of AMPs-bacteria clusters with overall negatively surface charge improved AMPs transport in quartz sand.
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Affiliation(s)
- Lei He
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
| | - Haifeng Rong
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
| | - Meng Li
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
| | - Mengya Zhang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
| | - Sirui Liu
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, PR China
| | - Meng Yang
- Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, PR China.
| | - Meiping Tong
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China.
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7
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Bai H, Lamy E. Bacteria transport and deposition in an unsaturated aggregated porous medium with dual porosity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:18963-18976. [PMID: 32342416 DOI: 10.1007/s11356-020-08783-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Bacterial transport and deposition play an important role in the assessment and prediction of subsurface pollution risks. Bacteria transport experiments were performed under unsaturated flow conditions in an aggregated porous medium at the laboratory column scale, to investigate how the inter- and intra-aggregated pore space of this medium could affect transport and deposition under unsaturated flow conditions, where inter- and intra-pore spaces are not fully activated. The results obtained through experimental observations and numerical simulations showed that some intra- and inter-pore space of this medium was excluded from bacteria transport and retention, as confirmed by the non-uniform transport of bacteria pathways in the aggregated porous media under unsaturated flow conditions. Capillary energy was higher the than other forces acting at bacteria air-water-solid interfaces. If this energy should contribute in increasing bacteria deposition under unsaturated conditions, similar to what has been reported for sandy media, similar overall retention of E. coli and R. rhodochrous was obtained under unsaturated flow conditions, suggesting that capillary energy was not the driving force for bacteria deposition.
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Affiliation(s)
- Hongjuan Bai
- School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, 450001, People's Republic of China
- Département de Génie des Procédés Industriels, Laboratoire TIMR, Université de Technologie de Compiègne - Alliance Sorbonne Université, F-60205, Compiègne cedex, France
| | - Edvina Lamy
- Département de Génie des Procédés Industriels, Laboratoire TIMR, Université de Technologie de Compiègne - Alliance Sorbonne Université, F-60205, Compiègne cedex, France.
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8
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Ramazanpour Esfahani A, Batelaan O, Hutson JL, Fallowfield HJ. Transport and retention of graphene oxide nanoparticles in sandy and carbonaceous aquifer sediments: Effect of physicochemical factors and natural biofilm. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 278:111419. [PMID: 33126193 DOI: 10.1016/j.jenvman.2020.111419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/25/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
There is a paucity of information regarding the interaction between GONPs and natural aquifer sediments. Therefore, batch and column experiments were carried out to determine the transport, retention and attachment behavior of GONPs with the surfaces of native aquifer sediments. The experiments were performed with sediments comprising contrasting mineralogical features (sand grains, quartz and limestone sediments), at different temperatures, ionic strength and compositions. Uniquely, this research also investigated the effect of natural biofilm on the retention behavior of nanoparticles in porous media. The retention rate of GONPs at 22 °C was higher than at 4 °C. Moreover, there was greater retention of GONPs onto the surfaces of collectors at higher ionic strengths and cation valence. The retention profiles (RPs) of GONPs in pristine porous media at low ionic strength were linear, which contrasted with hyper-exponential shape of RPs at high ionic strength. The size-distribution analysis of retained GONPs showed decreasing particle diameter with increasing distance from the column inlet at high ionic strength and equal diameter at low ionic strengths. The GONP retention rate was higher for natural porous media than for sand, due to the presence of metal oxides heterogeneities. The presence of biofilm on porous media increased the retention rate of GONPs when compared to the porous media in the absence of biofilm.
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Affiliation(s)
- Amirhosein Ramazanpour Esfahani
- College of Science and Engineering, Flinders University, Adelaide, Australia; National Centre for Groundwater Research and Training, SA, 5001, Australia.
| | - Okke Batelaan
- College of Science and Engineering, Flinders University, Adelaide, Australia; National Centre for Groundwater Research and Training, SA, 5001, Australia
| | - John L Hutson
- College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Howard J Fallowfield
- College of Science and Engineering, Flinders University, Adelaide, Australia; National Centre for Groundwater Research and Training, SA, 5001, Australia
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Li X, Ding W, Tan S, Zeng X. Stability of Nano-ZnO in simulated landfill leachate containing heavy metal ions. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 198:110641. [PMID: 32353603 DOI: 10.1016/j.ecoenv.2020.110641] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/11/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
As the presence of nanosized zinc oxide particles (nano-ZnO) in landfill leachate increases, their interaction with coexisting heavy metal ions (HMs) also increases. The interface interaction between nano-ZnO and HMs will influence nano-ZnO stability and therefore affect its bioavailability and environmental impact. In the present study, we investigated the effects of Cu(II), Cr(III), and Cr(VI) ions on the aggregation, sedimentation, and dissolution of nano-ZnO using batch experiments with a view to better understanding their co-effect on the environment. Dynamic light scattering and UV-Vis spectroscopy results show enhanced aggregation of nano-ZnO in the presence of Cr(VI) ions under fresh landfill leachate conditions, in addition to distinct sedimentation of nano-ZnO in the presence of Cr(III) ions in both fresh and aged landfill leachate. In fresh leachate, Cu(II) ions improved the concentration of dissolved Zn from nano-ZnO. However, the effects of Cu(II), Cr(III), and Cr(VI) ions on the aggregation and dissolution of nano-ZnO were markedly reduced in aged landfill leachate. Both acetic and humic acids in landfill leachate significantly affected the stability of nano-ZnO in the presence of HMs. According to the ATR-FTIR results, Cr(III) ions reacted with hydroxyl groups on nano-ZnO to form ZnO-O bonds, which induced chains of nano-ZnO and Cr(III) complexes, and hence the increased of nano-ZnO aggregates. ATR-FTIR shows merely electrostatic adsorption effects between nano-ZnO and Cu(II) or Cr(VI) ions. In brief, the mode of interactions between HMs and nano-ZnO influenced the stability via adsorption and binding effects. The results of the present research provide insight into the potential effects of nano-ZnO on the environment in the presence of HMs in landfill leachate.
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Affiliation(s)
- Xiaoyu Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education, Chongqing University, Chongqing, 400045, China; School of Urban Construction and Environmental Engineering, Chongqing University, Chongqing, 400044, China
| | - Wenchuan Ding
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, State Ministry of Education, Chongqing University, Chongqing, 400045, China; School of Urban Construction and Environmental Engineering, Chongqing University, Chongqing, 400044, China.
| | - Siying Tan
- School of Urban Construction and Environmental Engineering, Chongqing University, Chongqing, 400044, China
| | - Xiaolan Zeng
- National Center for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing, 400045, China; School of Urban Construction and Environmental Engineering, Chongqing University, Chongqing, 400044, China
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He L, Rong H, Wu D, Li M, Wang C, Tong M. Influence of biofilm on the transport and deposition behaviors of nano- and micro-plastic particles in quartz sand. WATER RESEARCH 2020; 178:115808. [PMID: 32371288 DOI: 10.1016/j.watres.2020.115808] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 05/20/2023]
Abstract
Biofilm, community of bacteria ubiquitously present in natural environment, may interact with plastic particles and affect the transport of plastic particles in environment. The significance of biofilm (Escherichia coli) on the transport and deposition behaviors of three different sized plastic particles (0.02 μm NPs, 0.2 μm MP and 2 μm MP) were examined under both 10 mM and 50 mM NaCl solutions by comparing the breakthrough curves and retained profiles of plastic particles in bare sand versus those in biofilm-coated sand. Regardless of ionic strengths, the presence of biofilm increases the deposition of all three sized plastic particles in porous media. Via employing X-ray microtomography imaging (XMT) and Scanning electron microscope (SEM), we find that the presence of biofilm could narrow the flow path especially near to the inlet of the column and increase the surface roughness of porous media (by decreasing DLVO repulsive interaction), which contributes to the enhanced the deposition of plastic particles. Extracellular polymeric substances (EPS) present on the biofilm are found to contribute to the enhanced deposition of plastic particles. Packed column experiments, quartz crystal microbalance with dissipation (QCM-D) as well as parallel plate flow chamber experiments all show that three major components of EPS, proteins, polysaccharide, and humic substances all contribute to the enhanced deposition of plastic particles. O-H and N-H groups present on cell surfaces are highly likely to form hydrogen bond with plastic particles and increase the deposition plastic particles. Elution experiments show that decreasing solution ionic strength could release small portion of plastic particles from both bare and biofilm-coated sand columns especially from the segments near to the column inlet (with slighter lower percentage from biofilm-coated columns based on the total mass of retained plastics). In contrast, increasing flow rate does not obviously detach the plastic particles that already deposited onto porous media. The results of this study clearly show that the presence of biofilm in natural environment could enhance the deposition and decrease the transport of plastic particles.
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Affiliation(s)
- Lei He
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China
| | - Haifeng Rong
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China
| | - Dan Wu
- Beijing Institute of Metrology, Beijing, 100029, PR China
| | - Meng Li
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China
| | - Chengyi Wang
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China
| | - Meiping Tong
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, PR China.
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Xu N, Li Z, Huangfu X, Cheng X, Christodoulatos C, Qian J, Chen M, Chen J, Su C, Wang D. Facilitated transport of nTiO 2-kaolin aggregates by bacteria and phosphate in water-saturated quartz sand. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 713:136589. [PMID: 31958725 PMCID: PMC7252603 DOI: 10.1016/j.scitotenv.2020.136589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/12/2019] [Accepted: 01/06/2020] [Indexed: 05/06/2023]
Abstract
The soil major component of clay plays an important role in governing the fate and transport of engineered nanomaterials (e.g., the most commonly used titanium dioxide nanoparticles; nTiO2) in the subsurface environments via forming nTiO2-clay aggregates. This research is designed to unravel the interplay of naturally-occurring bacteria (Escherichia coli) and phosphate on the transport and retention of nTiO2-kaolin aggregates in water-saturated porous media. Our results showed that nTiO2-nTiO2 homoaggregates and nTiO2-kaolin heteroaggregates dominated in the nTiO2-kaolin nanoaggregate suspension. Transport of nTiO2-kaolin aggregates was enhanced with the copresence of E. coli and phosphate, particularly at the low pH of 6.0. This effect is due to the greater adsorption of phosphate and thus the greater enhancement in repulsive interaction energies between aggregates and sand grains at pH 6.0 (vs. pH 9.0). The charged "soft layer" of E. coli cell surfaces changed the aggregation state and the heterogeneous distribution of nTiO2-kaolin aggregates, and subsequently stabilized the nTiO2-nTiO2 homoaggregates and nTiO2-kaolin heteroaggregates via TEM-EDX measurements and promoted the physical segregation between the aggregates (separation distance = 0.486 vs. 0.614 μm without vs. with the presence of E. coli) via 2D/3D AFM identifications, both of which caused greater mobility of nTiO2-kaolin aggregates with the presence of E. coli. Nonetheless, transport of nTiO2-kaolin aggregates was lower with the copresence of E. coli and phosphate vs. the singular presence of phosphate due to the competitive adsorption of less negatively charged E. coli (vs. phosphate) onto the aggregates. Taken altogether, our findings furnish new insights into better understanding the fate, transport, and potential risks of nTiO2 in real environmental settings (soil and sediment aquifer) where clay, bacteria, and phosphate ubiquitously cooccur.
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Affiliation(s)
- Nan Xu
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Zuling Li
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Xinxing Huangfu
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Xueying Cheng
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Christos Christodoulatos
- Center for Environmental System, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA
| | - Junchao Qian
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Ming Chen
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jianping Chen
- Jiangsu Key Laboratory of Intelligent Building Energy Efficiency, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Chunming Su
- Groundwater Characterization and Remediation Division, Center for Environmental Solutions and Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Ada, OK 74820, USA
| | - Dengjun Wang
- Oak Ridge Institute for Science and Education, United States Environmental Protection Agency, Ada, OK 74820, USA.
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12
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Wang X, Liu B, Pan X, Gadd GM. Transport and retention of biogenic selenium nanoparticles in biofilm-coated quartz sand porous media and consequence for elemental mercury immobilization. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 692:1116-1124. [PMID: 31539943 DOI: 10.1016/j.scitotenv.2019.07.309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/15/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
Bacterial biofilms are structured cell communities embedded in a matrix of extracellular polymeric substances (EPS) and a ubiquitous growth form of bacteria in the environment. A wide range of interactions between biofilms and nanoparticles have been reported. In the present study, the influence of a mixed bacterial biofilm on retention of biogenic selenium nanoparticles (BioSeNPs) and consequences for immobilization of elemental mercury (Hg0) in a porous quartz sand system were examined. BioSeNPs were significantly retained in the presence of a biofilm through electrical double layer effects, hydrogen bonding, and hydrophobic, steric and bridging interactions. Moreover, enhanced surface roughness, pore clogging, sieving and entrapment effects mediated by the biofilm also contributed to deposition of BioSeNPs. Whereas, thiol groups associated with the biofilm is a little helpful for the capture of Hg0. It is proposed that oxidative complexation between Hg0 and thiol compounds or S containing organic matter in the biofilm may result in the formation of Hg2+-thiolate complexes and HgS during the binding of Hg0 with BioSeNPs. The formation of mercury selenide was also involved in Hg0 immobilization in the porous quartz sand system.
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Affiliation(s)
- Xiaonan Wang
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China; Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Bingshen Liu
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangliang Pan
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
| | - Geoffrey Michael Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
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13
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Tang Y, Wang X, Yan Y, Zeng H, Wang G, Tan W, Liu F, Feng X. Effects of myo-inositol hexakisphosphate, ferrihydrite coating, ionic strength and pH on the transport of TiO 2 nanoparticles in quartz sand. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:1193-1201. [PMID: 31252117 DOI: 10.1016/j.envpol.2019.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 05/18/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Evaluating the fate and transport of nanoparticles (NPs) in the subsurface environment is critical for predicting the potential risks to both of the human health and environmental safety. It is believed that numerous environmental factors conspire to control the transport dynamics of nanoparticles, yet the effects of organic phosphates on nanoparticles transport remain largely unknown. In this work, we quantified the transport process of TiO2 nanoparticle (nTiO2) and their retention patterns in water-saturated sand columns under various myo-inositol hexakisphosphate (IHP) or phosphate (Pi) concentrations (0-180 μM P), ferrihydrite coating fractions (λ, 0-30%), ionic strengths (1-50 mM KCl), and pH values (4-8). The transport of nTiO2 was enhanced at increased P concentration due to the enhanced colloidal stability. As compared with Pi at the equivalent P level, IHP showed stronger effect on the electrokinetic properties of nTiO2 particles due to its relatively more negative charge and higher adsorption affinity, thereby facilitating the nTiO2 transport (and thus reduced retention) in porous media. At the IHP concentration of 5 μM, the retention of nTiO2 increased with increasing λ and ionic strength, while decreased with pH. In addition, the retention profiles of nTiO2 showed a typical hyperexponential pattern for most scenarios mainly due to the unfavorable attachment, and can be well described by a hybrid mathematical model that coupled convection dispersion equations with a two-site kinetic model and DLVO theory. These quantitative estimations revealed the importance of IHP on affecting the transport of nTiO2 typically in phosphorus-enriched environments. It provides new insights into advanced understanding of the co-transport of nanoparticles and phosphorus in natural systems, essential for both nanoparticle exposure and water eutrophication.
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Affiliation(s)
- Yadong Tang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Xiaoming Wang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Yupeng Yan
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Huan Zeng
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Gang Wang
- Department of Soil and Water Sciences, China Agricultural University, Beijing, 100193, China
| | - Wenfeng Tan
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Fan Liu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China
| | - Xionghan Feng
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agriculture University, Wuhan, 430070, China.
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14
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Xu N, Huangfu X, Li Z, Wu Z, Li D, Zhang M. Nanoaggregates of silica with kaolinite and montmorillonite: Sedimentation and transport. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 669:893-902. [PMID: 30970456 DOI: 10.1016/j.scitotenv.2019.03.099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/02/2019] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Due to a wide range of applications in industrial fields, engineered nanomaterials (ENMs) have a high potential to enter the soil. The soil's major component of clay likely dictates the fate and transport of ENMs in the subsurface. Currently, few studies are available on the fate and transport of nanoparticle silica (nSiO2) in the presence of clay particles. Therefore, the sedimentation and transport of nSiO2 with two representative clays (montmorillonite (M) and kaolin (K)) in porous media were investigated in monovalent (Na+) and divalent (Ca2+) ion solutions with multiple characterizations including SEM/TEM-EDX, zeta potentials, particle sizes and colloid transport modeling. It was shown that nSiO2-nSiO2 homoaggregates and nSiO2-K (or M) heteroaggregates dominated in the nSiO2-clay nanoaggregate suspension. A distinct decrease in the stability and transport of nSiO2-M (or K) in NaCl solution and an increase in CaCl2 occurred when M or K was added to the nSiO2 suspension at pH 6.0. This was attributed to the faster settlement of the individual M or K in NaCl vs. the better stability in CaCl2 (compared to nSiO2 alone). Particularly, more negative individual M platelets occurred in the high NaCl solution until extensive flocculated structures built up, which contributed to the faster deposition of nSiO2-M compared to nSiO2-K, even though the nSiO2-M was more negatively charged. Comparably, the effect of M and K on the fate and transport of nSiO2 almost disappeared at pH 9.0. The values of the first-order attachment/detachment rate coefficients (k1/k1d) and first-order straining coefficient (k2) obtained from two-site kinetic attachment model fitting are responsible for the deposition of nSiO2-clay nanoaggregates in sand. This study suggests potential groundwater contamination due to the clay-facilitated transport of ENMs in calcareous soil.
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Affiliation(s)
- Nan Xu
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Xinxing Huangfu
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Zuling Li
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Zhengying Wu
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Duo Li
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Mo Zhang
- Jiangsu Key Laboratory of Environmental Functional Materials, School of Chemistry Biology and Material Engineering, Suzhou University of Science and Technology, Suzhou 215009, China
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15
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Huangfu X, Xu Y, Liu C, He Q, Ma J, Ma C, Huang R. A review on the interactions between engineered nanoparticles with extracellular and intracellular polymeric substances from wastewater treatment aggregates. CHEMOSPHERE 2019; 219:766-783. [PMID: 30572231 DOI: 10.1016/j.chemosphere.2018.12.044] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 11/18/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
Engineered nanoparticles (ENPs) will inevitably enter wastewater treatment plants (WWTPs) due to their widespread application; thus, it is necessary to study the migration and transformation of nanoparticles in sewage treatment systems. Extracellular polymeric substances (EPSs) such as polysaccharides, proteins, nucleic acids, humic acids and other polymers are polymers released by microorganisms under certain conditions. Intracellular polymeric substances (IPSs) are microbial substances contained in the body with compositions similar to those of extracellular polymers. In this review, we summarize the characteristics of EPSs and IPSs from sewage-collecting microbial aggregates containing pure bacteria, activated sludge, granular sludge and biofilms. We also further investigate the dissolution, adsorption, aggregation, deposition, oxidation and other chemical transformation processes of nanoparticles, such as metals, metal oxides, and nonmetallic oxides. In particular, the review deeply analyzes the migration and transformation mechanisms of nanoparticles in EPS and IPS matrices, including physical, chemical, biological interactions mechanisms. Moreover, various factors, such as ionic strength, ionic valence, pH, light, oxidation-reduction potential and dissolved oxygen, influencing the interaction mechanisms are discussed. In recent years, studies on the interactions between EPSs/IPSs and nanoparticles have gradually increased, but the mechanisms of these interactions are seldom explored. Therefore, developing a systematic understanding of the migration and transformation mechanisms of ENPs is significant.
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Affiliation(s)
- Xiaoliu Huangfu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China.
| | - Yanghui Xu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China
| | - Caihong Liu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China
| | - Qiang He
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China.
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, China
| | - Chengxue Ma
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China
| | - Ruixing Huang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Faculty of Urban Construction and Environmental Engineering, Chongqing University 400044, China
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16
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Babakhani P, Bridge J, Doong RA, Phenrat T. Continuum-based models and concepts for the transport of nanoparticles in saturated porous media: A state-of-the-science review. Adv Colloid Interface Sci 2017. [PMID: 28641812 DOI: 10.1016/j.cis.2017.06.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Environmental applications of nanoparticles (NP) increasingly result in widespread NP distribution within porous media where they are subject to various concurrent transport mechanisms including irreversible deposition, attachment/detachment (equilibrium or kinetic), agglomeration, physical straining, site-blocking, ripening, and size exclusion. Fundamental research in NP transport is typically conducted at small scale, and theoretical mechanistic modeling of particle transport in porous media faces challenges when considering the simultaneous effects of transport mechanisms. Continuum modeling approaches, in contrast, are scalable across various scales ranging from column experiments to aquifer. They have also been able to successfully describe the simultaneous occurrence of various transport mechanisms of NP in porous media such as blocking/straining or agglomeration/deposition/detachment. However, the diversity of model equations developed by different authors and the lack of effective approaches for their validation present obstacles to the successful robust application of these models for describing or predicting NP transport phenomena. This review aims to describe consistently all the important NP transport mechanisms along with their representative mathematical continuum models as found in the current scientific literature. Detailed characterizations of each transport phenomenon in regards to their manifestation in the column experiment outcomes, i.e., breakthrough curve (BTC) and residual concentration profile (RCP), are presented to facilitate future interpretations of BTCs and RCPs. The review highlights two NP transport mechanisms, agglomeration and size exclusion, which are potentially of great importance in controlling the fate and transport of NP in the subsurface media yet have been widely neglected in many existing modeling studies. A critical limitation of the continuum modeling approach is the number of parameters used upon application to larger scales and when a series of transport mechanisms are involved. We investigate the use of simplifying assumptions, such as the equilibrium assumption, in modeling the attachment/detachment mechanisms within a continuum modelling framework. While acknowledging criticisms about the use of this assumption for NP deposition on a mechanistic (process) basis, we found that its use as a description of dynamic deposition behavior in a continuum model yields broadly similar results to those arising from a kinetic model. Furthermore, we show that in two dimensional (2-D) continuum models the modeling efficiency based on the Akaike information criterion (AIC) is enhanced for equilibrium vs kinetic with no significant reduction in model performance. This is because fewer parameters are needed for the equilibrium model compared to the kinetic model. Two major transport regimes are identified in the transport of NP within porous media. The first regime is characterized by higher particle-surface attachment affinity than particle-particle attachment affinity, and operative transport mechanisms of physicochemical filtration, blocking, and physical retention. The second regime is characterized by the domination of particle-particle attachment tendency over particle-surface affinity. In this regime although physicochemical filtration as well as straining may still be operative, ripening is predominant together with agglomeration and further subsequent retention. In both regimes careful assessment of NP fate and transport is necessary since certain combinations of concurrent transport phenomena leading to large migration distances are possible in either case.
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17
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Chrysikopoulos CV, Sotirelis NP, Kallithrakas-Kontos NG. Cotransport of Graphene Oxide Nanoparticles and Kaolinite Colloids in Porous Media. Transp Porous Media 2017. [DOI: 10.1007/s11242-017-0879-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Garner KL, Suh S, Keller AA. Assessing the Risk of Engineered Nanomaterials in the Environment: Development and Application of the nanoFate Model. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:5541-5551. [PMID: 28443660 DOI: 10.1021/acs.est.6b05279] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We developed a dynamic multimedia fate and transport model (nanoFate) to predict the time-dependent accumulation of metallic engineered nanomaterials (ENMs) across environmental media. nanoFate considers a wider range of processes and environmental subcompartments than most previous models and considers ENM releases to compartments (e.g., urban, agriculture) in a manner that reflects their different patterns of use and disposal. As an example, we simulated ten years of release of nano CeO2, CuO, TiO2, and ZnO in the San Francisco Bay area. Results show that even soluble metal oxide ENMs may accumulate as nanoparticles in the environment in sufficient concentrations to exceed the minimum toxic threshold in freshwater and some soils, though this is more likely with high-production ENMs such as TiO2 and ZnO. Fluctuations in weather and release scenario may lead to circumstances where predicted ENM concentrations approach acute toxic concentrations. The fate of these ENMs is to mostly remain either aggregated or dissolved in agricultural lands receiving biosolids and in freshwater or marine sediments. Comparison to previous studies indicates the importance of some key model aspects including climatic and temporal variations, how ENMs may be released into the environment, and the effect of compartment composition on predicted concentrations.
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Affiliation(s)
- Kendra L Garner
- Bren School of Environmental Science & Management, University of California , SantaBarbara, California 93106, United States
| | - Sangwon Suh
- Bren School of Environmental Science & Management, University of California , SantaBarbara, California 93106, United States
| | - Arturo A Keller
- Bren School of Environmental Science & Management, University of California , SantaBarbara, California 93106, United States
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19
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Goldberg E, McNew C, Scheringer M, Bucheli TD, Nelson P, Hungerbühler K. What Factors Determine the Retention Behavior of Engineered Nanomaterials in Saturated Porous Media? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2729-2737. [PMID: 28139914 DOI: 10.1021/acs.est.6b05217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- Eli Goldberg
- Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Coy McNew
- Department
of Land, Air, and Water Resources, University of California, Davis, California 95616, United States
| | - Martin Scheringer
- Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
- RECETOX, Masaryk University, 625 00 Brno, Czech Republic
| | - Thomas D. Bucheli
- Agroscope Institute for Sustainability Sciences ISS, 8046 Zürich, Switzerland
| | - Peter Nelson
- Aware Engineering GmbH, 8050 Zürich, Switzerland
| | - Konrad Hungerbühler
- Institute
for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
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20
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He JZ, Wang DJ, Fang H, Fu QL, Zhou DM. Inhibited transport of graphene oxide nanoparticles in granular quartz sand coated with Bacillus subtilis and Pseudomonas putida biofilms. CHEMOSPHERE 2017; 169:1-8. [PMID: 27855326 DOI: 10.1016/j.chemosphere.2016.11.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 10/30/2016] [Accepted: 11/01/2016] [Indexed: 06/06/2023]
Abstract
Increasing production and use of graphene oxide nanoparticles (GONPs) boost their wide dissemination in the subsurface environments where biofilms occur ubiquitously, representative of the physical and chemical heterogeneities. This study aimed at investigating the influence of Gram-positive Bacillus subtilis (BS) and Gram-negative Pseudomonas putida (PP) biofilms on the transport of GONPs under different ionic strengths (0.1, 0.5, and 1.0 mM CaCl2) at neutral pH 7.2 in water-saturated porous media. Particularly, the X-ray micro-computed tomography was used to quantitatively characterize the pore structures of sand columns in the presence and absence of biofilms. Our results indicated that the presence of biofilms reduced the porosity and narrowed down the pore sizes of packed columns. Transport experiments in biofilm-coated sand showed that biofilms, irrespective of bacterial species, significantly inhibited the mobility of GONPs compared to that in cleaned sand. This could be due to the Ca2+ complexation, increased surface roughness and charge heterogeneities of collectors, and particularly enhanced physical straining caused by biofilms. The two-site kinetic retention model-fitted value of maximum solid-phase concentration (Smax2) for GONPs was higher for biofilm-coated sand than for cleaned sand, demonstrating that biofilms act as favorable sites for GONPs retention. Our findings presented herein are important to deepen our current understanding on the nature of particle-collector interactions.
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Affiliation(s)
- Jian-Zhou He
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Deng-Jun Wang
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, United States
| | - Huan Fang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing-Long Fu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-Mei Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
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21
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Kumari J, Chandrasekaran N, Nagarajan R, Mukherjee A. Individual, co-transport and deposition of TiO2 and ZnO nanoparticles over quartz sand coated with consortium biofilm. JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2016; 4:3954-3960. [DOI: 10.1016/j.jece.2016.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
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22
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Walden C, Zhang W. Biofilms Versus Activated Sludge: Considerations in Metal and Metal Oxide Nanoparticle Removal from Wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8417-8431. [PMID: 27437755 DOI: 10.1021/acs.est.6b01282] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The increasing application of metal and metal oxide nanoparticles [Me(O)NPs] in consumer products has led to a growth in concentration of these nanoparticles in wastewater as emerging contaminants. This may pose a threat to ecological communities (e.g., biological nutrient removal units) within treatment plants and those subject to wastewater effluents. Here, the toxicity, fate, and process implications of Me(O)NPs within wastewater treatment, specifically during activated sludge processing and biofilm systems are reviewed and compared. Research showed activated sludge achieves high removal rate of Me(O)NPs by the formation of aggregates through adsorption. However, recent literature reveals evidence that inhibition is likely for nutrient removal capabilities such as nitrification. Biofilm systems were much less studied, but show potential to resist Me(O)NP inhibition and achieve removal through possible retention by sorption. Implicating factors during bacteria-Me(O)NP interactions such as aggregation, surface functionalization, and the presence of organics are summarized. At current modeled levels, neither activated sludge nor biofilm systems can achieve complete removal of Me(O)NPs, thus allowing for long-term environmental exposure of diverse biological communities to Me(O)NPs in streams receiving wastewater effluents. Future research directions are identified throughout in order to minimize the impact of these nanoparticles released.
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Affiliation(s)
- Connie Walden
- Graduate Research Assistant, Department of Civil Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Wen Zhang
- Assistant Professor, Department of Civil Engineering, University of Arkansas , Fayetteville, Arkansas 72701, United States
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23
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Gentile GJ, Fidalgo de Cortalezzi MM. Enhanced retention of bacteria by TiO2 nanoparticles in saturated porous media. JOURNAL OF CONTAMINANT HYDROLOGY 2016; 191:66-75. [PMID: 27258326 DOI: 10.1016/j.jconhyd.2016.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/11/2016] [Accepted: 05/22/2016] [Indexed: 06/05/2023]
Abstract
The simultaneous transport of TiO2 nanoparticles and bacteria Pseudomonas aeruginosa in saturated porous media was investigated. Nanoparticle and bacterium size and surface charge were measured as a function of electrolyte concentration. Sand column breakthrough curves were obtained for single and combined suspensions, at four different ionic strengths. DLVO and classical filtration theories were employed to model the interactions between particles and between particles and sand grains. Attachment of TiO2 to the sand was explained by electrostatic forces and these nanoparticles acted as bonds between the bacteria and the sand, leading to retention. Presence of TiO2 significantly increased the retention of bacteria in the sand bed, but microorganisms were released when nanomaterial influx ceased. The inclusion of nanomaterials in saturated porous media may have implications for the design and operation of sand filters in water treatment.
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Affiliation(s)
- Guillermina J Gentile
- Department of Chemical Engineering, Instituto Tecnológico de Buenos Aires, Av. Eduardo Madero 399, 1106 Buenos Aires, Argentina.
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Chen Q, Xu S, Liu Q, Masliyah J, Xu Z. QCM-D study of nanoparticle interactions. Adv Colloid Interface Sci 2016; 233:94-114. [PMID: 26546115 DOI: 10.1016/j.cis.2015.10.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/04/2015] [Accepted: 10/05/2015] [Indexed: 12/25/2022]
Abstract
Quartz crystal microbalance with dissipation monitoring (QCM-D) has been proven to be a powerful research tool to investigate in situ interactions between nanoparticles and different functionalized surfaces in liquids. QCM-D can also be used to quantitatively determine adsorption kinetics of polymers, DNA and proteins from solutions on various substrate surfaces while providing insights into conformations of adsorbed molecules. This review aims to provide a comprehensive overview on various important applications of QCM-D, focusing on deposition of nanoparticles and attachment-detachment of nanoparticles on model membranes in complex fluid systems. We will first describe the working principle of QCM-D and DLVO theory pertinent to understanding nanoparticle deposition phenomena. The interactions between different nanoparticles and functionalized surfaces for different application areas are then critically reviewed. Finally, the potential applications of QCM-D in other important fields are proposed and knowledge gaps are identified.
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25
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Han P, Zhou D, Tong M, Kim H. Effect of bacteria on the transport and deposition of multi-walled carbon nanotubes in saturated porous media. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 213:895-903. [PMID: 27038577 DOI: 10.1016/j.envpol.2016.03.058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/20/2016] [Accepted: 03/22/2016] [Indexed: 06/05/2023]
Abstract
The influence of bacteria on the transport and deposition behaviors of carbon nanotubes (CNTs) in quartz sand was examined in both NaCl (5 and 25 mM ionic strength) and CaCl2 (0.3 and 1.2 mM ionic strength) solutions at unadjusted pH (5.6-5.8) by direct comparison of both breakthrough curves and retained profiles in both the presence and absence of bacteria. Two types of widely utilized CNTs, i.e., carboxyl- and hydroxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH and MWCNT-OH, respectively), were employed as model CNTs and Escherichia coli was utilized as the model bacterium. The results showed that, for both types of MWCNTs under all examined conditions, the breakthrough curves were higher in the presence of bacteria, while the retained profiles were lower, indicating that the co-presence of bacteria in suspension increased the transport and decreased the deposition of MWCNTs in porous media, regardless of ionic strength or ion valence. Complementary characterizations and extra column tests demonstrated that competition by bacteria for deposition sites on the quartz sand surfaces was a major (and possibly the sole) contributor to the enhanced MWCNTs transport in porous media.
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Affiliation(s)
- Peng Han
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Dan Zhou
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Meiping Tong
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
| | - Hyunjung Kim
- Department of Mineral Resources and Energy Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do, 561-756, Republic of Korea.
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26
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Mitzel MR, Sand S, Whalen JK, Tufenkji N. Hydrophobicity of biofilm coatings influences the transport dynamics of polystyrene nanoparticles in biofilm-coated sand. WATER RESEARCH 2016; 92:113-120. [PMID: 26845456 DOI: 10.1016/j.watres.2016.01.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/06/2016] [Accepted: 01/12/2016] [Indexed: 06/05/2023]
Abstract
Engineered nanoparticles (ENPs) are used in the manufacture of over 2000 industrial and consumer products to enhance their material properties and functions or to enable new nanoparticle-dependent functions. The widespread use of ENPs will result in their release to the subsurface and aquatic environments, where they will interact with indigenous biota. Laboratory column experiments were designed to understand the influence of two different Pseudomonas aeruginosa biofilms on the mobility of polystyrene latex nanoparticles in granular porous media representative of groundwater aquifers or riverbank filtration settings. The transport behavior of 20 nm carboxylate-modified (CLPs) and sulfate (SLPs) polystyrene latex ENPs suspended in NaCl or CaCl2 (1 and 10 mM ionic strength, pH 7) was studied in columns packed with quartz sand coated with biofilms formed by two P. aeruginosa strains that differed in cell surface hydrophobicity (P. aeruginosa 9027™, relatively hydrophilic and P. aeruginosa PAO1, relatively hydrophobic). Biofilm-coated quartz sand retained more of the electrostatically-stabilized latex ENPs than clean, uncoated sand, regardless of the serotype. As IS increased, clear differences in the shape of the ENP breakthrough curves were observed for each type of biofilm coating. ENP breakthrough in the P. aeruginosa PAO1 biofilm-coated sand was generally constant with time whereby breakthrough in the P. aeruginosa 9027 biofilm-coated sand showed dynamic behavior. This indicates a fundamental difference in the mechanisms of ENP deposition onto hydrophilic or hydrophobic biofilm coatings due to the hydration properties of these biofilms. The results of this study demonstrate the importance of considering the surface properties of aquifer grain coatings when evaluating ENP fate in natural subsurface environments.
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Affiliation(s)
- Michael R Mitzel
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada; Department of Natural Resource Sciences, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Stefanie Sand
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada; Department of Water Science, Universität Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany
| | - Joann K Whalen
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, H3A 0C5, Canada
| | - Nathalie Tufenkji
- Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada.
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27
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Han Y, Hwang G, Kim D, Bradford SA, Lee B, Eom I, Kim PJ, Choi SQ, Kim H. Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating. WATER RESEARCH 2016; 90:247-257. [PMID: 26741396 DOI: 10.1016/j.watres.2015.12.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/21/2015] [Accepted: 12/06/2015] [Indexed: 06/05/2023]
Abstract
The transport, retention, and long-term release of zinc oxide nanoparticle aggregates (denoted below as ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and the ionic strength (IS) was 0.1 or 10 mM NaCl, and the retention profiles were always hyper-exponential. Increasing the solution IS and biofilm coating produced enhanced retention of ZnO-NPs near the column inlet. The enhanced NPs retention at high IS was attributed to more favorable NP-silica and NP-NP interactions; this was consistent with the interaction energy calculations. Meanwhile, the greater NPs retention in the presence of biofilm was attributed to larger roughness heights which alter the mass transfer rate, the interaction energy profile, and lever arms associated with the torque balance; e.g., scanning electron and atomic force microscopy was used to determine roughness heights of 33.4 nm and 97.8 nm for bare sand and biofilm-coated sand, respectively. Interactions between NPs and extracellular polymeric substances may have also contributed to enhanced NP retention in biofilm-coated sand at low IS. The long-term release of retained ZnO-NPs was subsequently investigated by continuously injecting NP-free solution at pH 6, 9, or 10 and keeping the IS constant at 10 mM. The amount and rate of retained ZnO-NP removal was strongly dependent on the solution pH. Specifically, almost complete removal of retained ZnO-NPs was observed after 627 pore volumes when the solution pH was 6, whereas much less Zn was recovered when the eluting solution pH was buffered to pH = 9 and especially 10. This long-term removal was attributed to pH-dependent dissolution of retained ZnO-NPs because: (i) the solubility of ZnO-NPs increases with decreasing pH; and (ii) ZnO-NPs were not detected in the effluent. The presence of biofilm also decreased the initial rate and amount of dissolution and the subsequent transport of Zn(2+) due to the strong Zn(2+) re-adsorption to the biofilm. Our study indicates that dissolution will eventually lead to the complete removal of retained ZnO-NPs and the transport of toxic Zn(2+) ions in groundwater environments with pH ranges of 5-9.
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Affiliation(s)
- Yosep Han
- Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea
| | - Gukhwa Hwang
- Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea
| | - Donghyun Kim
- Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea
| | | | - Byoungcheun Lee
- Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea
| | - Igchun Eom
- Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea
| | - Pil Je Kim
- Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea
| | - Siyoung Q Choi
- Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 305-701, Republic of Korea
| | - Hyunjung Kim
- Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea.
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Retention of titanium dioxide nanoparticles in biological activated carbon filters for drinking water and the impact on ammonia reduction. Biodegradation 2016; 27:95-106. [PMID: 26931341 DOI: 10.1007/s10532-016-9758-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 02/25/2016] [Indexed: 01/12/2023]
Abstract
Given the increasing discoveries related to the eco-toxicity of titanium dioxide (TiO2) nanoparticles (NPs) in different ecosystems and with respect to public health, it is important to understand their potential effects in drinking water treatment (DWT). The effects of TiO2 NPs on ammonia reduction, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in biological activated carbon (BAC) filters for drinking water were investigated in static and dynamic states. In the static state, both the nitrification potential and AOB were significantly inhibited by 100 μg L(-1) TiO2 NPs after 12 h (p < 0.05), and the threshold decreased to 10 μg L(-1) with prolonged exposure (36 h, p < 0.05). However, AOA were not considerably affected in any of the tested conditions (p > 0.05). In the dynamic state, different amounts of TiO2 NP pulses were injected into three pilot-scale BAC filters. The decay of TiO2 NPs in the BAC filters was very slow. Both titanium quantification and scanning electron microscope analysis confirmed the retention of TiO2 NPs in the BAC filters after 134 days of operation. Furthermore, the TiO2 NP pulses considerably reduced the performance of ammonia reduction. This study identified the retention of TiO2 NPs in BAC filters and the negative effect on the ammonia reduction, suggesting a potential threat to DWT by TiO2 NPs.
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Jian-Zhou H, Cheng-Cheng L, Deng-Jun W, Zhou DM. Biofilms and extracellular polymeric substances mediate the transport of graphene oxide nanoparticles in saturated porous media. JOURNAL OF HAZARDOUS MATERIALS 2015. [PMID: 26223021 DOI: 10.1016/j.jhazmat.2015.07.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Understanding the fate and transport of graphene oxide nanoparticles (GONPs) in the subsurface environments is of crucial importance since they may pose potential risks to the environment and human health. However, little is known about the significance of biofilm on mobility of GONPs in the subsurface. Here we investigated the transport of GONPs in saturated sand coated with Bacillus subtilis (Gram-positive) and Pseudomonas putida (Gram-negative) biofilms, and their secreted extracellular polymeric substances (EPS) under environmentally relevant ionic strengths (1-50mM NaCl) at pH 7.2. Our results showed that irrespective of bacteria type, greater retention of GONPs occurred in biofilm-coated sand compared to clean sand, likely attributed to the increased surface roughness and physical straining. However, EPS showed negligible influence on GONPs transport, which was inconsistent with the findings in the presence of biofilms, while they exhibited comparable ζ-potentials. The different retention phenotype of GONPs in the presence of EPS was induced by hydration effect and steric repulsion. A two-site kinetic retention model well-described the transport of GONPs in porous media covered with different surface coatings, which proves the applicability of mathematical model in predicting nanoparticles' mobility in the subsurface environments, when considering the potential effects of biofilm and EPS.
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Affiliation(s)
- He Jian-Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Cheng-Cheng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wang Deng-Jun
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Dong-Mei Zhou
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
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Kurlanda-Witek H, Ngwenya BT, Butler IB. The influence of biofilms on the mobility of bare and capped zinc oxide nanoparticles in saturated sand and glass beads. JOURNAL OF CONTAMINANT HYDROLOGY 2015; 179:160-170. [PMID: 26140853 DOI: 10.1016/j.jconhyd.2015.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/26/2015] [Accepted: 06/23/2015] [Indexed: 06/04/2023]
Abstract
Biofilms are a common constituent of the subsurface and are known to influence contaminant transport; however only a few studies to date have addressed microbial controls on nanoparticle mobility in porous media. The impact of a 3-day Pantoea agglomerans biofilm on the mobility of zinc oxide (ZnO) nanoparticles was studied in column experiments containing sand and glass beads at near-neutral pH and constant ionic strength. Bare ZnO nanoparticles (bZnO-NPs) and ZnO nanoparticles capped with tri-aminopropyltriethoxysilane (cZnO-NPs) were used in the experiments. Breakthrough curves demonstrate that the biofilm particularly slowed nanoparticle migration of bZnO-NPs in glass bead columns and cZnO-NPs in sand columns. With the exception of bZnO-NPs in sand columns, biofilm-coated porous media retained more nanoparticles than those of controls without biofilm. The biofilm may bear an impact on the surface charge of the porous medium, nullifying porous medium-specific effects. Although viable cell counts (VCCs) decreased after the introduction of electrolyte and before nanoparticle transport experiments, SEM and CLSM imaging of porous medium samples taken from columns after nanoparticle transport experiments, as well as total organic carbon (TOC) measurements reveal that biofilm was present in the columns throughout the experiments. Hence, it can be concluded that even a thin amount of biofilm can hinder nanoparticle migration in small-scale porous medium experiments. Moreover, nanoparticle mobility is dependent on the binding capacity of biofilms, rather than the type of porous media.
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Affiliation(s)
- H Kurlanda-Witek
- Mott MacDonald Polska Sp. z o.o., ul. Waliców 11, 00-851 Warsaw, Poland.
| | - B T Ngwenya
- School of GeoSciences, University of Edinburgh Kings Buildings, West Mains Rd, EH9 3JW Edinburgh, United Kingdom
| | - I B Butler
- School of GeoSciences, University of Edinburgh Kings Buildings, West Mains Rd, EH9 3JW Edinburgh, United Kingdom
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Dual Roles of Capsular Extracellular Polymeric Substances in Photocatalytic Inactivation of Escherichia coli: Comparison of E. coli BW25113 and Isogenic Mutants. Appl Environ Microbiol 2015; 81:5174-83. [PMID: 26002903 DOI: 10.1128/aem.00775-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/19/2015] [Indexed: 12/11/2022] Open
Abstract
The dual roles of capsular extracellular polymeric substances (EPS) in the photocatalytic inactivation of bacteria were demonstrated in a TiO2-UVA system, by comparing wild-type Escherichia coli strain BW25113 and isogenic mutants with upregulated and downregulated production of capsular EPS. In a partition system in which direct contact between bacterial cells and TiO2 particles was inhibited, an increase in the amount of EPS was associated with increased bacterial resistance to photocatalytic inactivation. In contrast, when bacterial cells were in direct contact with TiO2 particles, an increase in the amount of capsular EPS decreased cell viability during photocatalytic treatment. Taken together, these results suggest that although capsular EPS can protect bacterial cells by consuming photogenerated reactive species, it also facilitates photocatalytic inactivation of bacteria by promoting the adhesion of TiO2 particles to the cell surface. Fluorescence microscopy and scanning electron microscopy analyses further confirmed that high capsular EPS density led to more TiO2 particles attaching to cells and forming bacterium-TiO2 aggregates. Calculations of interaction energy, represented by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) potential, suggested that the presence of capsular EPS enhances the attachment of TiO2 particles to bacterial cells via acid-base interactions. Consideration of these mechanisms is critical for understanding bacterium-nanoparticle interactions and the photocatalytic inactivation of bacteria.
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32
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Chen IC, Zhang M, Teipel B, de Araujo IS, Yegin Y, Akbulut M. Transport of polymeric nanoparticulate drug delivery systems in the proximity of silica and sand. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:3575-3583. [PMID: 25695909 DOI: 10.1021/es504188a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The contamination of the environment with traditional therapeutics due to metabolic excretion, improper disposal, and industrial waste has been well-recognized. However, knowledge of the environmental distribution and fate of emerging classes of nanomedicine is scarce. This work investigates the effect of surface chemistry of polymeric nanoparticulate drug delivery systems (PNDDS) on their adsorption dynamics and transport in the vicinity of environmentally relevant surfaces for a concentration comparable with hospital and pharmaceutical manufacturing effluents. To this end, five different types of paclitaxel-based nanomedicine having different polymer stabilizers were employed. Their transport behavior was characterized via quartz crystal microbalance, sand column, spectrofluorometry, and dynamic light scattering techniques. PNDDS having positive zeta-potential displayed strong adsorption onto silica surfaces and no mobility in porous media of quartz sand, even in the presence of humic acid. The mobility of negatively charged PNDDS strongly depended on the amount and type of salt present in the aqueous media: Without any salt, such PNDDS demonstrated no adsorption on silica surfaces and high levels of mobility in sand columns. The presence of CaCl2 and CaSO4, even at low ionic strengths (i.e. 10 mM), induced PNDDS adsorption on silica surfaces and strongly limited the mobility of such PNDSS in sand columns.
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Sun P, Shijirbaatar A, Fang J, Owens G, Lin D, Zhang K. Distinguishable transport behavior of zinc oxide nanoparticles in silica sand and soil columns. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 505:189-198. [PMID: 25461021 DOI: 10.1016/j.scitotenv.2014.09.095] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/23/2014] [Accepted: 09/27/2014] [Indexed: 06/04/2023]
Abstract
As part of ongoing risk assessments of ZnO nanoparticles (nZnO) in the natural environment, transport behaviors of nZnO in soil need investigation. This work comparatively studied the transport and retention behavior of nZnO in silica sand versus soil, where the effect of input concentration (C₀=34~430 mgL(-1)) and ionic strength (IS=1~50 mM) were investigated. In silica sand, nZnO were highly mobile, especially at low C₀ and the efflux of nZnO generally decreased with increasing C₀ at all tested IS. Conversely, at low C₀, n ZnO were almost entirely immobile in soil and the efflux of nZnO increased with C₀ at all tested IS. In both media, the retention profiles (RPs) were generally hyper-exponentially shaped suggesting nZnO easily deposited near the column inlet. As indicated by DLVO calculations, previously deposited nZnO on the silica sand surface acted as new deposition sites due to the lower energy barrier (Φmax) between nZnO-nZnO than between nZnO-silica sand. However, previously deposited nZnO in soil could enhance Φmax between the soil surface and nZnO which resulted in unfavorable sites for nZnO deposition. The two-site kinetic attachment model provided good descriptions for the breakthrough curves of nZnO. Detachment was more significant than attachment in silica sand (k₁d>k₁a), whereas soil surface attachment of nZnO were strong and irreversible (k₁a>k₁d). The straining interaction parameter (k₂str) increased with increasing C0 in silica sand, but decreased with C0 in soil. Such differences were mainly responsible for the various transport behaviors of nZnO in silica sand and soil.
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Affiliation(s)
- Peide Sun
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, P. R. China
| | - Altantuya Shijirbaatar
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, P. R. China
| | - Jing Fang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, P. R. China.
| | - Gary Owens
- Environmental Contaminants Group, Mawson Institute, University of South Australia, Mawson Lakes, South Australia SA 5095, Australia
| | - Daohui Lin
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, P. R. China
| | - Keke Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, P. R. China
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Goldberg E, Scheringer M, Bucheli TD, Hungerbühler K. Critical assessment of models for transport of engineered nanoparticles in saturated porous media. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:12732-12741. [PMID: 25256358 DOI: 10.1021/es502044k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To reliably assess the fate of engineered nanoparticles (ENP) in soil, it is important to understand the performance of models employed to predict vertical ENP transport. We assess the ability of seven routinely employed particle transport models (PTMs) to simulate hyperexponential (HE), nonmonotonic (NM), linearly decreasing (LD), and monotonically increasing (MI) retention profiles (RPs) and the corresponding breakthrough curves (BTCs) from soil column experiments with ENPs. Several important observations are noted. First, more complex PTMs do not necessarily perform better than simpler PTMs. To avoid applying overparameterized PTMs, multiple PTMs should be applied and the best model selected. Second, application of the selected models to simulate NM and MI profiles results in poor model performance. Third, the selected models can well-approximate LD profiles. However, because the models cannot explicitly generate LD retention, these models have low predictive power to simulate the behavior of ENPs that present LD profiles. Fourth, a term for blocking can often be accounted for by parameter variation in models that do not explicitly include a term for blocking. We recommend that model performance be analyzed for RPs and BTCs separately; simultaneous fitting to the RP and BTC should be performed only under conditions where sufficient parameter validation is possible to justify the selection of a particular model.
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Affiliation(s)
- Eli Goldberg
- Institute for Chemical and Bioengineering, ETH Zürich , 8093 Zürich, Switzerland
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Lu Y, Yang K, Lin D. Transport of surfactant-facilitated multiwalled carbon nanotube suspensions in columns packed with sized soil particles. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 192:36-43. [PMID: 24880534 DOI: 10.1016/j.envpol.2014.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/30/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
Transport of carbon nanotubes (CNTs) in soil/sediment matrixes can regulate their potential eco-effects and has been however rarely studied. Herein, column experiments were conducted to investigate mobility of CNT suspensions stabilized by dodecylbenzenesulfonic acid sodium salt (SDBS), octyl-phenol-ethoxylate (TX-100) and cetylpyridinium chloride (CPC) in four soil samples with certain particle sizes. Humic acid was extracted from a soil sample and was coated on quartz sands to explore the effect of soil organic matter (SOM) on the mobility. Results showed that the positively-charged CPC-CNT was entirely retained in the columns while the negatively-charged SDBS-CNT and TX-100-CNT more or less broke through the columns. Pearson correlation analyses revealed that soil texture rather than SOM controlled the mobility. Electrostatic attraction to and/or precipitation on the grain surfaces together with the straining effect could explain the CNT retention. These novel results will help to understand the eco-effects of CNTs.
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Affiliation(s)
- Yinying Lu
- Zhejiang University, Department of Environmental Science, Hangzhou 310058, China
| | - Kun Yang
- Zhejiang University, Department of Environmental Science, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- Zhejiang University, Department of Environmental Science, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China.
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Kurlanda-Witek H, Ngwenya BT, Butler IB. Transport of bare and capped zinc oxide nanoparticles is dependent on porous medium composition. JOURNAL OF CONTAMINANT HYDROLOGY 2014; 162-163:17-26. [PMID: 24796515 DOI: 10.1016/j.jconhyd.2014.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 04/02/2014] [Accepted: 04/04/2014] [Indexed: 06/03/2023]
Abstract
Zinc oxide (ZnO) nanoparticles are one of the most frequently used nanoparticles in industry and hence are likely to be introduced to the groundwater environment. The mobility of these nanoparticles in different aquifer materials has not been assessed. While some studies have been published on the transport of ZnO nanoparticles in individual porous media, these studies do not generally account for varying porous medium composition both within and between aquifers. As a first step towards understanding the impact of this variability, this paper compares the transport of bare ZnO nanoparticles (bZnO-NPs) and capped ZnO nanoparticles, coated with tri-aminopropyltriethoxysilane (cZnO-NPs), in saturated columns packed with glass beads, fine grained sand and fine grained calcite, at near-neutral pH and groundwater salinity levels. With the exception of cZnO-NPs in sand columns, ZnO nanoparticles are highly immobile in all three types of studied porous media, with most retention taking place near the column inlet. Results are in general agreement with DLVO theory, and the deviation in experiments with cZnO-NPs flowing through columns packed with sand is linked to variability in zeta potential of the capped nanoparticles and sand grains. Therefore, differences in surface charge of nanoparticles and porous media are demonstrated to be key drivers in nanoparticle transport.
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Affiliation(s)
| | - B T Ngwenya
- School of GeoSciences, University of Edinburgh, Kings Buildings, West Mains Rd, EH9 3JW Edinburgh, United Kingdom
| | - I B Butler
- School of GeoSciences, University of Edinburgh, Kings Buildings, West Mains Rd, EH9 3JW Edinburgh, United Kingdom
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Han Y, Kim D, Hwang G, Lee B, Eom I, Kim PJ, Tong M, Kim H. Aggregation and dissolution of ZnO nanoparticles synthesized by different methods: Influence of ionic strength and humic acid. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2014.03.030] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mitzel MR, Tufenkji N. Transport of industrial PVP-stabilized silver nanoparticles in saturated quartz sand coated with Pseudomonas aeruginosa PAO1 biofilm of variable age. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2715-2723. [PMID: 24552618 DOI: 10.1021/es404598v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the environmental fate and transport of engineered nanoparticles (ENPs) is of paramount importance for the formation and validation of regulatory guidelines regarding these new and increasingly prevalent materials. The present study assessed the transport of an industrial formulation of poly(vinylpyrrolidone)-stabilized silver nanoparticle (PVP-nAg) in columns packed with water-saturated quartz sand and the same sand coated with Pseudomonas aeruginosa PAO1 biofilm of variable age (i.e., growth period). Physicochemical characterization studies indicate that the PVP-nAg is stable in suspension and exhibits little change in size or electrophoretic mobility with changing ionic strength (IS) in either NaNO3 or Ca(NO3)2. The collector surface had a relatively homogeneous biofilm coating, as determined by CLSM, and a near uniform distribution of biomass and biofilm thickness following column equilibration. Transport experiments in clean sand revealed changes in the particle deposition behavior only at and above 10 mM IS Ca(NO3)2 and showed no discernible change in PVP-nAg transport behavior in the presence of 1 to 100 mM NaNO3. Transport experiments in P. aeruginosa-coated sand indicated significantly reduced retention of PVP-nAg at low IS compared to clean sand, irrespective of biofilm age. Nanoparticle retention was also generally reduced in the biofilm-coated sand at the higher IS, but to a lesser extent. The decreased retention of PVP-nAg in biofilm-coated sand compared to clean sand is likely due to repulsive electrosteric forces between the PVP coatings and extracellular polymeric substances (EPS) of the biofilm. Additionally, the slope of the rising portion of the PVP-nAg breakthrough curve was noticeably steeper in biofilm conditions than in clean sand. More mature biofilm coating also resulted in earlier breakthrough of PVP-nAg compared to younger biofilm coatings, or to the clean sand, which may be an indication of the effect of repulsive surface forces combined with selective pore size exclusion from the pores of denser, more developed biofilm. These results, when considered with other literature, indicate the importance in considering the flow dynamics, pore network and structure, the effective particle size, and particle permeability with regard to the biofilm matrix when considering the possible influence of biofilms on ENP transport.
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Affiliation(s)
- Michael R Mitzel
- Department of Chemical Engineering and ‡Department of Natural Resource Sciences, McGill University , Montreal, Quebec H3A 0C5, Canada
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Li L, Schuster M. Influence of phosphate and solution pH on the mobility of ZnO nanoparticles in saturated sand. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 472:971-978. [PMID: 24355393 DOI: 10.1016/j.scitotenv.2013.11.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/12/2013] [Accepted: 11/12/2013] [Indexed: 06/03/2023]
Abstract
The mobility of nanoparticles (NPs) strongly depends on the chemical characterization of the environmental medium. However, the influence of phosphate on NPs mobility was ignored by scientists despite the serious phosphate contamination in natural environments. Hence, the influence of phosphate and solution pH on the mobility of zinc oxide nanoparticles (ZnO-NPs) was investigated in water-saturated sand representative of groundwater aquifers, which encompassed a range of P/Zn molar ratios (P/Zn: 0-4) and pH (4.8-10.0). The transport of ZnO-NPs was dramatically enhanced in the presence of phosphate, even at a low P/Zn molar ratio namely 0.25, and the retention of ZnO-NPs in the saturated sand decreased with increasing P/Zn molar ratio. Moreover, attachment efficiencies (α) and deposition rates (kd) of ZnO-NPs rapidly decreased with increasing P/Zn molar ratio. In contrast, the solution pH had negligible effects on ZnO-NP transport behavior under phosphate-abundant condition (P/Zn: 4). The distinct effects may be explained by the energy interaction between ZnO-NPs and sand surface under different conditions. Interestingly, under phosphate-abundant condition (P/Zn: 4), solution pH could strongly affect the transport of Zn(2+) in the water-saturated sand. Overall, this study outlines the importance of taking account of phosphate into risk assessment of NPs in the environment.
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Affiliation(s)
- Lingxiangyu Li
- Institute of Water Quality Control, Technische Universität München, Am Coulombwall 8, 85747 Garching, Germany; Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany
| | - Michael Schuster
- Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany.
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Lu Y, Xu X, Yang K, Lin D. The effects of surfactants and solution chemistry on the transport of multiwalled carbon nanotubes in quartz sand-packed columns. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 182:269-277. [PMID: 23948360 DOI: 10.1016/j.envpol.2013.07.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/15/2013] [Accepted: 07/18/2013] [Indexed: 06/02/2023]
Abstract
The effect of different surfactants on the transport of multiwalled carbon nanotubes (MWCNTs) in quartz sand-packed columns was firstly investigated under various conditions. The stable plateau values (C(max)) of the breakthrough curves (BTCs), critical PVs (the number of pore volumes of infusions needed to reach the C(max)), maximum transport distances (L(max)), deposition rate coefficients (kd) and retention rates were calculated to compare the transport and retention of MWCNTs under various conditions. Stability of the MWCNT suspensions as a function of the influencing factors was examined to reveal the underlying mechanism of the MWCNT retention. Results showed that MWCNTs suspended by different surfactants presented different BTCs; the MWCNT transport increased with increasing sand size and MWCNT concentration; high flow velocity was favorable for the MWCNT transport, while high Ca(2+) concentration and low pH were unfavorable for the transport; hetero-aggregation, straining and site blocking occurred during the transport.
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Affiliation(s)
- Yinying Lu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
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