1
|
Gong L, Ying S, Xia C, Pan K, He F. Carboxymethyl cellulose stabilization induced changes in particle characteristics and dechlorination efficiency of sulfidated nanoscale zero-valent iron. CHEMOSPHERE 2024; 355:141726. [PMID: 38521105 DOI: 10.1016/j.chemosphere.2024.141726] [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: 11/24/2023] [Revised: 02/13/2024] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
Polymer stabilization, exemplified by carboxymethyl cellulose (CMC), has demonstrated effectiveness in enhancing the transport of nanoscale zero-valent iron (nZVI). And, sulfidation is recognized for enhancing the reactivity and selectivity of nZVI in dechlorination processes. The influence of polymer stabilization on sulfidated nZVI (S-nZVI) with various sulfur precursors remains unclear. In this study, CMC-stabilized S-nZVI (CMC-S-nZVI) was synthesized using three distinct sulfur precursors (S2-, S2O42-, and S2O32-) through one-step approach. The antioxidant properties of CMC significantly elevated the concentration of reduced sulfur species (S2-) on CMC-S-nZVIs, marking a 3.1-7.0-fold increase compared to S-nZVIs. The rate of trichloroethylene degradation (km) by CMC-S-nZVIs was observed to be 2.2-9.0 times higher than that achieved by their non-stabilized counterparts. Among the three CMC-S-nZVIs, CMC-S-nZVINa2S exhibited the highest km. Interesting, while the electron efficiency of CMC-S-nZVIs surged by 7.9-12 times relative to nZVI, it experienced a reduction of 7.0-34% when compared with S-nZVIs. This phenomenon is attributed to the increased hydrophilicity of S-nZVI particles due to CMC stabilization, which inadvertently promotes the hydrogen evolution reaction (HER). In conclusion, the findings of this study underscores the impact of CMC stabilization on the properties and dechlorination performance of S-nZVI sulfidated using different sulfur precursors, offering guidance for engineering CMC-S-nZVIs with desirable properties for contaminated groundwater remediation.
Collapse
Affiliation(s)
- Li Gong
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Shuaixuan Ying
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Chenyun Xia
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Ke Pan
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China
| | - Feng He
- College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China; Institute of Environmental Processes and Pollution Control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
| |
Collapse
|
2
|
Mondal A, Mumford K, Dubey BK, Arora M. Effect of solution chemistry on the sedimentation, dissolution, and aggregation of the bimetallic Fe/Cu nanoparticles pre- and post-grafted with carboxymethyl cellulose. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170966. [PMID: 38367731 DOI: 10.1016/j.scitotenv.2024.170966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/29/2024] [Accepted: 02/12/2024] [Indexed: 02/19/2024]
Abstract
The suitability of iron-based nanomaterials or composites for in-situ remediation hinges on their physicochemical stability. Introducing surface modifications like metal doping or polymer grafting can regulate interparticle forces, influencing particle stability. Thus, probing how grafting methods (i.e., pre- or post-grafting) tune material properties controlling interparticle forces, comprehend the synergistic effect of metal doping and polymer grafting, and evaluate stability under varying geochemical conditions are the way forward in designing sustainable remediation strategies. To this end, time-dependent sedimentation, dissolution, and aggregation of four synthesized iron-based nanoparticles (bare iron (Fe), copper doped bimetallic iron/copper (Fe/Cu), pre- and post-grafted Fe/Cu with carboxymethyl cellulose (CMC) - CMCpre-Fe/Cu and CMCpost-Fe/Cu, respectively) were carried out as a function of solution chemistry (i.e., pH - 5 to 10, ionic strength, IS - 0 to 100 mM NaCl, initial particle concentration, C0-20 to 200 mg.L-1) mimicking geoenvironmental conditions. CMCpre-Fe/Cu exhibited markedly higher particle availability (> 91 %) against sedimentation than others (bare Fe/Cu (11.28 %) > bare Fe (7.33 %) > CMCpost-Fe/Cu (6.09 %)) - suggesting the pivotal role of grafting method on particle stability. XDLVO energy profiles revealed pre-grafting altered magnetic properties favoring surface charge-driven electrostatic repulsion over magnetic attraction, thereby limiting aggregation-induced particle settling. In contrast, superior magnetic force overrides the electrostatic behavior for bare and post-grafted particles. Unlike bare and post-grafted nanoparticles, CMCpre-Fe/Cu aggregate size correlated positively with [H+] and IS, consistent with their settling behavior. Rise in C0 showed a visible negative effect on particle aggregation and, thereby, sedimentation except for CMCpre-Fe/Cu by facilitating particle collision through Brownian movement. Both acidic pH and copper doping promoted nanoparticle dissolution, whereas pre-grafting can provide a plausible solution against nanoparticle toxicity and loss of reactivity due to ionic release. To recapitulate, these findings are imperative in building a sustainable framework for environmental remediation application.
Collapse
Affiliation(s)
- Abhisek Mondal
- Department of Infrastructure Engineering, The University of Melbourne, Melbourne, Australia; Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Kathryn Mumford
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Australia.
| | - Brajesh K Dubey
- Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Meenakshi Arora
- Department of Infrastructure Engineering, The University of Melbourne, Melbourne, Australia
| |
Collapse
|
3
|
Turkeltaub T, Weisbrod N, Zavarin M, Chang E, Kersting AB, Teutsch N, Roded S, Tran EL, Geller Y, Gerera Y, Klein-BenDavid O. Radionuclide transport in fractured chalk under abrupt changes in salinity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168636. [PMID: 37981163 DOI: 10.1016/j.scitotenv.2023.168636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/21/2023]
Abstract
Internationally, it has been agreed that geologic repositories for spent fuel and radioactive waste are considered the internationally agreed upon solution for intermediate and long-term disposal. In countries where traditional nuclear waste repository host rocks (e.g., clay, salt, granite) are not available, other low permeability lithologies must be studied. Here, chalk is considered to determine its viability for disposal. Despite chalk's low bulk permeability, it may contain fracture networks that can facilitate radionuclide transport. In arid areas, groundwater salinity may change seasonally due to the mixing between brackish groundwater and fresh meteoric water. Such salinity changes may impact the radionuclides' mobility. In this study, radioactive U(VI) and radionuclide simulant tracers (Sr, Ce and Re) were injected into a naturally fractured chalk core. The mobility of tracers was investigated under abrupt salinity variations. Two solutions were used: a low ionic strength (IS) artificial rainwater (ARW; IS ∼0.002) and a high IS artificial groundwater (AGW; IS ∼0.2). During the experiments, the tracers were added to ARW, then the carrier was changed to AGW, and vice versa. Ce was mobile only in colloidal form, while Re was transported as a conservative tracer. Both Re and Ce demonstrated no change in mobility due to salinity changes. In contrast, U and Sr showed increased mobility when AGW was introduced and decreased mobility when ARW was introduced into the core. These experimental results, supported by reactive transport modeling, suggest that saline groundwater solutions promote U and Sr release via ion-exchange and enhance their migration in fractured chalk. The study emphasizes the impact of salinity variations near spent fuel repositories and their possible impact on radionuclide mobility.
Collapse
Affiliation(s)
- Tuvia Turkeltaub
- The Zuckerburg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel.
| | - Noam Weisbrod
- The Zuckerburg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel
| | - Mavrik Zavarin
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94550, USA
| | - Elliot Chang
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94550, USA
| | - Annie B Kersting
- Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94550, USA
| | - Nadya Teutsch
- Geological Survey of Israel, 32 Yeshayahu Leibowitz St., Jerusalem 9371234, Israel
| | - Sari Roded
- The Zuckerburg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel
| | - Emily L Tran
- The Zuckerburg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel; Now at Shamir Research Institute, University of Haifa, Qatsrin 1290000, Israel
| | - Yehonatan Geller
- Geological and Environmental Science Department, Ben Gurion University of the Negev, Beersheva 8410501, Israel
| | - Yarden Gerera
- The Zuckerburg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel
| | - Ofra Klein-BenDavid
- Nuclear Research Center of the Negev, Negev, P.O. Box 9001, Beersheva 8419001, Israel; Geological and Environmental Science Department, Ben Gurion University of the Negev, Beersheva 8410501, Israel
| |
Collapse
|
4
|
Yu K, Lv Y, Liu C, Boyd SA, Teppen BJ, Li H. Reaction of decabromodiphenyl ether with organo-modified clay-templated zero-valent iron in water-tetrahydrofuran solution: Nano- to micrometric scale effects. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130538. [PMID: 37055959 PMCID: PMC10105828 DOI: 10.1016/j.jhazmat.2022.130538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/27/2022] [Accepted: 12/01/2022] [Indexed: 06/19/2023]
Abstract
Smectite clay-templated nanoscale zero-valent iron (CZVI) was modified with tetramethylammonium (TMA), trimethylphenylammonium (TMPA) and hexadecyltrimethylammonium (HDTMA) to achieve organoclay-templated ZVI (OCZVI). The reactivity of various OCZVIs was evaluated on the basis of degradation of decabromodiphenyl ether (DBDE) in tetrahydrofuran (THF)-water binary solution. Characterization of OCZVI interlayer at nanometric scale indicated that the clay particles had the domains with three basal spacings in the THF/water solution. In the 50 % THF solution TMPA modification promoted the formation of the domains with a basal spacing at 1.56 nm, which could promote the degradation of DBDE. At the micrometric scale, in the 90 % THF solution TMA and TMPA modification tended to enhance the aggregation of OCZVI particles, while the HDTMA modification reduced the aggregation, and high percentage of modification yielded viscous gel structures. The relatively rapid sedimentation processes in 90 % THF solution (compared to that in 50 % THF solution) and formation gel structures could reduce the access of DBDE to the interlayer reactive nZVIs, and lead to the significant reduction in reaction rate. These results provide important insights to the organo-modification on clays which could alter their orientations and dispersion in organic-water binary solution to achieve the desired reactivity on confined clay surfaces.
Collapse
Affiliation(s)
- Kai Yu
- Nanchang Hangkong University, Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang, Jiangxi 330063, China; Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Yanni Lv
- Nanchang Hangkong University, Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang, Jiangxi 330063, China
| | - Cun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210008, China
| | - Stephen A Boyd
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Brian J Teppen
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Hui Li
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States.
| |
Collapse
|
5
|
Borgman O, Be'er A, Weisbrod N. Direct visualization of colloid transport over natural heterogeneous and artificial smooth rock surfaces. JOURNAL OF CONTAMINANT HYDROLOGY 2022; 251:104067. [PMID: 36113262 DOI: 10.1016/j.jconhyd.2022.104067] [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: 03/11/2022] [Revised: 08/13/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Colloid transport in fractured rock formations is an important process impacting the fate of pollutants in the subsurface. Despite intensive and outstanding research on their transport phenomena, the impact of small-scale surface heterogeneity on colloid behavior at the fracture scale remains difficult to assess. In particular, there is relatively little direct experimental evidence on the impact of natural fracture surface heterogeneity on colloid transport. To investigate this, we developed an experimental setup allowing the direct visualization of fluorescent colloid transport in a flow cell containing a natural chalk rock sample while simultaneously monitoring effluent colloid concentrations. We used samples containing both a natural fracture surface and an artificially made smooth surface from the same chalk core. We characterized the roughness and chemical composition of both surface types and numerically calculated each surface's velocity field. From the experiments, we obtained direct images of colloid transport over the surfaces, from which we calculated their dispersion coefficients and quantified the residual deposition of colloids on the rock surface. We also measured the colloid breakthrough curves by collecting eluent samples from the flow cell outlet. The natural fracture surface exhibited larger physical and chemical heterogeneity than the smooth, artificially generated surface. The aperture variability across the natural surface led to preferential flow and colloid transport which was qualitatively apparent in the fluorescent images. The colloid transport patterns matched the calculated velocity fields well, directly linking the surface topography and aperture variation to colloid transport. Compared to the artificially made surface, the natural surface also showed higher dispersion coefficients, which corresponded to the colloids' earlier breakthrough from the flow cell. While we found differences between the elemental composition of the natural and artificially smooth surfaces, we could not observe their impact on the colloids' surface attachment and retention. The main novelty in this work is the coupling of direct colloid transport imaging, breakthrough curve measurements, and colloid surface deposition analyses, in a flow cell containing a natural carbonate rock sample. Our experimental setup can be used to further investigate the link between surface heterogeneity, both chemical and physical, and colloid transport and deposition in natural rock fractures.
Collapse
Affiliation(s)
- Oshri Borgman
- Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 8499000, Israel; Univ Rennes, CNRS, Géosciences Rennes, UMR 6118, 35000 Rennes, France.
| | - Avraham Be'er
- Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 8499000, Israel
| | - Noam Weisbrod
- Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 8499000, Israel
| |
Collapse
|
6
|
Wu W, Chen X, Han L, Yang L, Gu M, Li J, Chen M. The evolution of stable nanohybrids to complex heteroaggregates between nZVI and soil nanoparticles: The influence of ionic strength and soil components. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129155. [PMID: 35596993 DOI: 10.1016/j.jhazmat.2022.129155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
The heteroaggregation mechanism of nZVI with four types of natural soil nanoparticles (SNPs) extracted from representative soils in northern and southern China was investigated. Heteroaggregation rates between nZVI and SNPs were quantified by dynamic light scattering and evaluated as a function of ionic strength at pH 7. The nZVI-SNPs heteroaggregates were stable with hydrodynamic diameters (Dh) ranging from 400 to 600 nm in 0.1 mM solution. Based on the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, nZVI underwent heteroaggregation with SNPs to form stable nZVI-SNPs nanohybrid due to the attachment of nZVI on the SNPs. However, with enhanced ionic strength, SNPs accelerated the aggregation of nZVI and formed large heteroaggregates with Dh in the range from 1200 to 2000 nm, owing to insignificant electrostatic repulsions and oppositely charged patches. In addition, the differences in the heteroaggregation rates of nZVI with four SNPs were negligible, caused by the negligible impacts of SNPs components such as soil organic matter and Fe/Al oxyhydroxides on the heteroaggregation of nZVI in the 10 mM NaCl solution. These findings are helpful for understanding the interaction between nZVI and SNPs and of significance to groundwater remediation using nZVI.
Collapse
Affiliation(s)
- Wenpei Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xueyan Chen
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Lu Han
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Lei Yang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Mingyue Gu
- Nanjing Kaiye Environmental Technology Co Ltd, 8 Yuanhua Road, Innovation Building 106, Nanjing University Science Park, Nanjing 210034, China
| | - Jing Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Mengfang Chen
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| |
Collapse
|
7
|
Zhang J, Hu H, Chao J, Tang Y, Wan P, Yuan Q, Fisher AC, Coulon F, Hu Q, Yang XJ. Groundwater remediation using Magnesium-Aluminum alloys and in situ layered doubled hydroxides. ENVIRONMENTAL RESEARCH 2022; 204:112241. [PMID: 34695428 DOI: 10.1016/j.envres.2021.112241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 10/08/2021] [Accepted: 10/16/2021] [Indexed: 06/13/2023]
Abstract
In situ remediation of groundwater by zerovalent iron (ZVI)-based technology faces the problems of rapid passivation, fast agglomeration, limited range of pollutants and secondary contamination. Here a new concept of Magnesium-Aluminum (Mg-Al) alloys and in situ layered double hydroxides on is proposed for the degradation and removal of a wide variety of inorganic and organic pollutants from groundwater. The Mg-Al alloy provides the electrons for the chemical reduction and/or the degradation of pollutants while released Mg2+, Al3+ and OH- ions react to generate in situ LDH precipitates, incorporating other divalent and trivalent metals and oxyanions pollutants and further adsorbing the micropollutants. The Mg-Al alloy outperforms ZVI for treating acidic, synthetic groundwater samples contaminated by complex chemical mixtures of heavy metals (Cd2+, Cr6+, Cu2+, Ni2+ and Zn2+), nitrate, AsO33-, methyl blue, trichloroacetic acid and glyphosate. Specifically, the Mg-Al alloy achieves removal efficiency ≥99.7% for these multiple pollutants at concentrations ranging between 10 and 50 mg L-1 without producing any secondary contaminants. In contrast, ZVI removal efficiency did not exceed 90% and secondary contamination up to 220 mg L-1 Fe was observed. Overall, this study provides a new alternative approach to develop efficient, cost-effective and green remediation for water and groundwater.
Collapse
Affiliation(s)
- Jingqi Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Hanjun Hu
- Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China; Beijing Huanding Environmental Big Data Institute, No. 1 Wangzhuang Road, Beijing, 100083, China
| | - Jingbo Chao
- National Institute of Metrology, Beijing, 100029, China
| | - Yang Tang
- National Fundamental Research Laboratory of New Hazardous Chemicals Assessment and Accident Analysis, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Pingyu Wan
- National Fundamental Research Laboratory of New Hazardous Chemicals Assessment and Accident Analysis, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Qipeng Yuan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Adrian C Fisher
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB2 1TN, UK
| | - Frederic Coulon
- School of Water, Energy and Environment, Cranfield University, Cranfield, MK43 0AL, UK
| | - Qing Hu
- Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China; Beijing Huanding Environmental Big Data Institute, No. 1 Wangzhuang Road, Beijing, 100083, China
| | - Xiao Jin Yang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| |
Collapse
|
8
|
Asad MA, Khan UT, Krol MM. Subsurface transport of carboxymethyl cellulose (CMC)-stabilized nanoscale zero valent iron (nZVI): Numerical and statistical analysis. JOURNAL OF CONTAMINANT HYDROLOGY 2021; 243:103870. [PMID: 34418819 DOI: 10.1016/j.jconhyd.2021.103870] [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: 11/12/2020] [Revised: 06/29/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Subsurface remediation using nanoscale zero valent iron (nZVI) is a promising in-situ technology that can transform certain groundwater contaminants into non-toxic compounds. However, field scale implementation of nZVI technology has faced major challenges due to poor subsurface mobility, limited longevity and well clogging, all leading to a shorter nZVI travel distance. This distance nZVI travels in the subsurface is an important parameter since it influences the amount of contaminants that can be reached and thereby remediated. There are several factors which may affect nZVI travel distance such as groundwater velocity, injection concentration and rate, lag period (duration when nZVI injection is stopped), solution viscosity, and subsurface heterogeneity. Although various studies have been performed to reveal the effect of different factors on nZVI transport in homogeneous domains, few studies have focused on heterogeneous media, which is more representative of field conditions. In this study, a statistical analysis was performed using a two-dimensional numerical model which simulated carboxymethyl cellulose (CMC) stabilized nZVI transport in randomly distributed soil permeability fields of two aquifers to examine the factors that have the greatest impact on nZVI travel distance. Among all possible factors, field scale solution viscosity and injection rate had a statistically significant effect on nZVI travel distance in both the horizontal and vertical directions, as well as, on the attached mass. Additionally, the lag period between injections had a statistically significant effect on the attached mass, but not the travel distance. These results suggest that having a long injection period followed by a short lag phase during field deployment may result in less nZVI attachment. Lastly, aquifer heterogeneity impacted the nZVI spread while the impact of intrinsic groundwater velocity and injection concentration was found not to be statistically significant. Results from this numerical study can aid in field-scale CMC-nZVI injection by identifying key factors for remediation optimization.
Collapse
Affiliation(s)
| | - Usman T Khan
- Civil Engineering, York University, Toronto, Ontario, Canada
| | | |
Collapse
|
9
|
Song Y, Lei C, Yang K, Lin D. Iron-carbon material enhanced electrokinetic remediation of PCBs-contaminated soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:118100. [PMID: 34492528 DOI: 10.1016/j.envpol.2021.118100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 08/14/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
The high toxicity and persistence of polychlorinated biphenyls (PCBs) in the environment demands the development of effective remediation for PCBs-contaminated soils. In this study, electrokinetic (EK) remediation integrated with iron-carbon material (Fe/C) was established and used to remediate PCB28 (1 mg kg-1) contaminated soil under a voltage gradient of 1 V cm-1. Effects of Fe/C dosage, soil type, and remediation time were investigated. The operational condition was optimized as 4 g kg-1 Fe/C, yellow soil, and 14 d-remediation, achieving PCB28 removal efficiency of 58.6 ± 8.8% and energy utilization efficiency of 146.5. Introduction of EK-Fe/C did not significantly affect soil properties except for slight soil moisture content increase and total Fe content loss. Soil electrical conductivity exhibited an increasing trend from anode to cathode attributed to EK-induced electromigration and electroosmosis. EK accelerated the corrosion and consumption of reactive Fe0/Fe3C in Fe/C by generating acid condition. Fe/C in turn effectively prevented EK-induced soil acidification and maintained soil neutral to weak alkaline condition. A synergistic effect between EK and Fe/C was revealed by the order of PCB28 removal efficiency-EK-Fe/C (58.6 ± 8.8%) > EK (37.7 ± 1.6%) > Fe/C (6.8 ± 5.0%). This could be primarily attributed to EK and Fe/C enhanced Fenton reaction, where EK promoted Fe/C dissolution and H2O2 generation. In addition to oxidation by Fenton reaction generated ·OH, EK-mediated electrochemical oxidation, Fe/C-induced reduction and migration of Fe/C adsorbed PCBs were all significant contributors to PCB28 removal in the EK-Fe/C system. These findings suggest that the combination of EK and Fe/C is a promising technology for remediation of organics-contaminated soil.
Collapse
Affiliation(s)
- Yan Song
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China
| | - Cheng Lei
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China
| | - Kun Yang
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, 310058, China
| | - Daohui Lin
- Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, 310058, China.
| |
Collapse
|
10
|
Wei X, Li X, Tang L, Yu J, Deng J, Luo T, Liang J, Chen X, Zhou Y. Exploring the role of Fe species from biochar-iron composites in the removal and long-term immobilization of SeO 42- against competing oxyanions. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126311. [PMID: 34118543 DOI: 10.1016/j.jhazmat.2021.126311] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/16/2021] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
Carbothermal reduction is a convenient and cost-effective method to produce biochar (BC) supported iron-based nano-particles (INP) for oxyanion contaminants removal. However, considering the possible desorption of the target oxyanion during change of the surrounding environment, the detailed removal mechanisms remain unclear and the long-term efficiency of different INPs cannot be predicted. In this study, different BC/Fe composites were synthesized by controlling the pyrolysis temperatures (500-800 °C). BC/Fe3O4 composite synthesized at 500 °C (BC/Fe500) possessed the strongest surface acidity thus with the best SeO42- removal performance, and BC/Fe0/Fe3O4 composite synthesized at 650 °C (BC/Fe650) possessed the best reducing ability toward SeO42-. Through the co-removal experiments (SeO42- and common competing oxyanions co-existed) and the investigation of Se stability loaded on BC/Fe composites, the removal of SeO42- by BC/Fe500 through highly reversible adsorption could not achieve long-term immobilization of Se, making it an appropriate adsorbent for pre-treatment only, while the efficient reduction of SeO42- to Se0 by BC/Fe650 could largely improve its long-term stability. This study supplies a possible strategy for Se immobilization against common competing oxyanions.
Collapse
Affiliation(s)
- Xue Wei
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Xiaodong Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Lin Tang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China.
| | - Jiangfang Yu
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Jiaqin Deng
- State Key Laboratory of Utilization of Woody Oil Resource, Hunan Academy of Forestry, Changsha 410004, China
| | - Ting Luo
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Jie Liang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Xuwu Chen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, China
| | - Yaoyu Zhou
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| |
Collapse
|
11
|
Ahn JY, Kim C, Jun SC, Hwang I. Field-scale investigation of nanoscale zero-valent iron (NZVI) injection parameters for enhanced delivery of NZVI particles to groundwater. WATER RESEARCH 2021; 202:117402. [PMID: 34273775 DOI: 10.1016/j.watres.2021.117402] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/26/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
The effects of the injection parameters on delivery of nanoscale zero-valent iron (NZVI) to contaminated groundwater were investigated. The first two NZVI injections (gravity injection at low flow rates) resulted in NZVI being poorly mobile and gave total cumulative mass recoveries at the monitoring wells of 1.07%-2.43%. NZVI reached some wells (KDMW-3, MW-2, MW-4, and MW-7) earlier than the bromide tracer. The dominant travel directions for NZVI and the bromide tracer were very different. The NZVI transport characteristics suggested that targeted NZVI delivery requires preferential groundwater flow paths and local heterogeneity to be considered. In the gravity injection tests, the maximum NZVI concentrations and cumulative NZVI mass recoveries in the wells decreased markedly as the injected NZVI concentration and dose increased. In the third and fourth tests, in which NZVI was injected under pressure at high flow rates, NZVI was effectively delivered to the wells despite the injected NZVI concentration and dose being high. Relatively high cumulative mass recoveries of 26.0% and 74.5% were found for the third and fourth injections, respectively. Controlling the flow rate (pressure) and NZVI concentration and dose simply and effectively controlled NZVI mobility in the groundwater. The colloidal and electrostatic characteristics of the NZVI particles were monitored and modeled, and the results indicated that NZVI particles without Derjaguin-Landau-Verwey-Overbeek energy barriers were successfully delivered to the target zone and that decreased magnetic attractive forces between NZVI particles caused by iron corrosion probably decreased the degree of NZVI particle aggregation and therefore contributed to NZVI being delivered to the target zone.
Collapse
Affiliation(s)
- Jun-Young Ahn
- Institute for Environment and Energy, Pusan National University, 2, Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Republic of Korea
| | - Cheolyong Kim
- Institute for Environment and Energy, Pusan National University, 2, Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Republic of Korea
| | - Seong-Chun Jun
- Geogreen21 Co. Ltd, 55 Digital-ro 33-gil, Guro-gu, Seoul 08376, Republic of Korea
| | - Inseong Hwang
- Department of Civil and Environmental Engineering, Pusan National University, 2, Busandaehak-ro 63 beon-gil, Geumjeong-gu, Busan 46241, Republic of Korea.
| |
Collapse
|
12
|
Wu W, Han L, Nie X, Gu M, Li J, Chen M. Effects of multiple injections on the transport of CMC-nZVI in saturated sand columns. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 784:147160. [PMID: 33901948 DOI: 10.1016/j.scitotenv.2021.147160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/27/2021] [Accepted: 04/11/2021] [Indexed: 06/12/2023]
Abstract
The multiple injections of nanoscale zero valent iron (nZVI) slurry, an efficient method to remediate contaminated groundwater, requires an accurate assessment of the transport and risks of these particles in saturated porous medium. However, the influencing mechanism of nZVI transport under multiple injection conditions is not fully understood. In this experimental study, one-dimensional sand columns were used to evaluate the effects of injection concentrations, particle sizes and surface chemical corrosion on the transport of carboxymethyl cellulose modified nZVI (CMC-nZVI) under triple injection conditions, where the different volumes of NaCl solution were flushed through the columns between the injections. Based on the breakthrough curves and retention profiles under flushing 4 pore volumes of NaCl solution between the injections, the transport of CMC-nZVI particles was gradually enhanced attributable to the exclusion among these particles at injection concentration of 200 mg/L, but the opposite was observed due to large aggregation caused by strong magnetic force among particles at 500 mg/L. However, the magnitudes of enhancement or reduction on maximum C/C0 under the above injection concentrations were related to the smallest particle size of Dh = 3.926 μm because of high particle number concentrations leading to intense competition on depositional sites at 200 mg/L and significant aggregation at 500 mg/L. Conversely, the transport of CMC-nZVI was reduced under flushing 76 pore volumes of NaCl solution between the injections because of pronounced corrosion of CMC-nZVI in water as evidenced by the XPS and XRD analyses of particles. This corrosion could cause the decrease in repulsion among particles due to the increase in surface negative zeta potential and the CMC desorption from nZVI. Accordingly, this study revealed that relative high injection concentrations and chemical corrosion in groundwater could restrain the mobility of nZVI under multiple injection conditions and the potential risks posed by CMC-nZVI are controllable.
Collapse
Affiliation(s)
- Wenpei Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Lu Han
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Xiang Nie
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Mingyue Gu
- Nanjing Kaiye Environmental Technology Co Ltd, 8 Yuanhua Road, Innovation Building 106, Nanjing University Science Park, Nanjing 210034, China
| | - Jing Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Mengfang Chen
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| |
Collapse
|
13
|
Sun YM, Feng L, Yang L. Degradation of PCB67 in soil using the heterogenous Fenton process induced by montmorillonite supported nanoscale zero-valent iron. JOURNAL OF HAZARDOUS MATERIALS 2021; 406:124305. [PMID: 33525129 DOI: 10.1016/j.jhazmat.2020.124305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 10/15/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
Montmorillonite supported nanoscale zero-valent iron (MMT-nZVI) was prepared and proved to be able to induce the heterogenous Fenton process for better removal of 2,3',4,5-tetrachlorobiphenyl (PCB67) in a long-term polluted soil. PCB67 removal depended highly on the dosages of MMT-nZVI and H2O2, and the initial pH, with the highest removal rate of 76.38% at conditions of H2O2 45.99 g·kg-1, MMT-nZVI 29.88 g·kg-1 and initial pH 3.5 after 80 min of reaction. Furthermore, PCB67 could be removed in a wider pH range (from 3.5 to near neutrality), with a loss of 13.6% in removal rate at neutral pH. With an activation energy of 21.4 kJ·mol-1, the degradation of PCB67 was an endothermic and diffusion-controlled process and followed the pseudo-first-order kinetics. That Fe2+ was supplied through aerobic corrosion of MMT-nZVI to activate H2O2 for·OH production was the possible mechanism of PCB67 degradation, leading to complete mineralization of PCB67 through two proposed pathways, with the intermediates of ethylbenzene and 3-hepten-2-one, as well as dibutyl phthalate and butyl acetate respectively.
Collapse
Affiliation(s)
- Yun-Man Sun
- Department of Environmental Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Liu Feng
- Department of Environmental Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
| | - Lei Yang
- Department of Environmental Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China
| |
Collapse
|
14
|
Tran E, Reimus P, Klein-BenDavid O, Teutsch N, Zavarin M, Kersting AB, Weisbrod N. Mobility of Radionuclides in Fractured Carbonate Rocks: Lessons from a Field-Scale Transport Experiment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11249-11257. [PMID: 32786561 PMCID: PMC7498145 DOI: 10.1021/acs.est.0c03008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/07/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Current research on radionuclide disposal is mostly conducted in granite, clay, saltstone, or volcanic tuff formations. These rock types are not always available to host a geological repository in every nuclear waste-generating country, but carbonate rocks may serve as a potential alternative. To assess their feasibility, a forced gradient cross-borehole tracer experiment was conducted in a saturated fractured chalk formation. The mobility of stable Sr and Cs (as analogs for their radioactive counterparts), Ce (an actinide analog), Re (a Tc analog), bentonite particles, and fluorescent dye tracers through the flow path was analyzed. The migration of each of these radionuclide analogs (RAs) was shown to be dependent upon their chemical speciation in solution, their interactions with bentonite, and their sorption potential to the chalk rock matrix. The brackish groundwater resulted in flocculation and immobilization of most particulate RAs. Nevertheless, the high permeability of the fracture system allowed for fast overall transport times of all aqueous RAs investigated. This study suggests that the geochemical properties of carbonate rocks may provide suitable conditions for certain types of radionuclide storage (in particular, brackish, high-porosity, and low-permeability chalks). Nevertheless, careful consideration should be given to high-permeability fracture networks that may result in high radionuclide mobility.
Collapse
Affiliation(s)
- Emily
L. Tran
- Zuckerberg
Institute for Water Research, Jacob Blaustein Institutes for Desert
Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel
| | - Paul Reimus
- Los
Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ofra Klein-BenDavid
- Nuclear
Research Center of the Negev, Negev,
P.O. Box 9001, Beersheva 8419001, Israel
- Geological
and Environmental Science Department, Ben
Gurion University of the Negev, Beersheva 8410501, Israel
| | - Nadya Teutsch
- Geological
Survey of Israel, 32 Yeshayahu Leibowitz Street, Jerusalem 9371234, Israel
| | - Mavrik Zavarin
- Lawrence
Livermore National Laboratory, Livermore, California 94550, United States
| | - Annie B. Kersting
- Lawrence
Livermore National Laboratory, Livermore, California 94550, United States
| | - Noam Weisbrod
- Zuckerberg
Institute for Water Research, Jacob Blaustein Institutes for Desert
Research, Ben Gurion University of the Negev, Midreshet Ben Gurion 8499000, Israel
| |
Collapse
|
15
|
Wan H, Islam MS, Qian D, Ormsbee L, Bhattacharyya D. Reductive Degradation of CCl 4 by Sulfidized Fe and Pd-Fe Nanoparticles: Kinetics, Longevity, and Morphology Aspects. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2020; 394:125013. [PMID: 33184558 PMCID: PMC7654737 DOI: 10.1016/j.cej.2020.125013] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In this study a systematic comparison in morphology, long-term degradation, regeneration and reuse were conducted between palladized and sulfidized nanoscale zero-valent iron (Pd-Fe and S-Fe). Pd-Fe and S-Fe were prepared, after the synthesis of precursor Fe0 nanoparticles (spherical, ~35 nm radius) for carbon tetrachloride (CTC) treatment. With HAADF-TEM-EDS characterization, dispersive Pd islets were found on the Fe core of Pd-Fe. However, the Fe core was covered by the FeSx shell of S-Fe (FeS/FeS2 = 0.47). With an excessive Pd dose (10 mol%), the Pd-Fe were dramatically deformed to dendritic structures which significantly decreased reactivity. For CTC degradation, Pd-Fe (0.3 atomic% Pd) increased the degradation rate by 20-fold (ksa= 0.580 Lm-2min-1) while S-Fe presented a greater life time. The major intermediate chloroform (CF) was further degraded and less than 5% CF was observed after 24 h using Pd-Fe or S-Fe while above 50% CF remained using Fe. During aging, the Fe core was converted to FeOOH and Fe3O4/γ-Fe2O3. The restoration of Fe0 was achieved using NaBH4, which regenerated Fe and Pd-Fe. However, the formed FeSx shell on S-Fe was disappeared. The results suggest that S-Fe extends longevity of Fe, but the loss of FeSx after aging makes S-Fe eventually perform like Fe in terms of CTC degradation.
Collapse
Affiliation(s)
- Hongyi Wan
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Mohammad Saiful Islam
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Dali Qian
- Electron Microscopy Center, College of Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Lindell Ormsbee
- Department of Civil Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| | - Dibakar Bhattacharyya
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046
| |
Collapse
|
16
|
Injection of Zerovalent Iron Gels for Aquifer Nanoremediation: Lab Experiments and Modeling. WATER 2020. [DOI: 10.3390/w12030826] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
One of the main technical problems faced during field-scale injections of iron microparticles (mZVI) for groundwater nanoremediation is related to their poor colloidal stability and mobility in porous media. In this study, a shear-thinning gel, composed of a mixture of two environmentally friendly biopolymers, i.e., guar gum and xanthan gum, was employed to overcome these limitations. The slurry rheology and particle mobility were characterized by column transport tests. Then, a radial transport experiment was performed to mimic the particle delivery in more realistic conditions. The gel, even at a low polymeric content (1.75 g/L), proved effective in enhancing the mobility of high concentrated mZVI suspensions (20 g/L) in field-like conditions. The high radius of influence (73 cm) and homogeneous iron distribution were achieved by maintaining a low injection overpressure (<0.4 bar). Based only on the information derived from column tests, the MNMs 2018 software (Micro- and Nanoparticle transport, filtration, and clogging Model-Suite) was able to predict the particle distribution and pressure build-up measured in the radial domain. Experimental and simulated results showed good agreement, thus proving that a simplified experimental-modeling procedure based on 1D column tests could be used to effectively upscale the slurry behavior to more representative scales, e.g., radial domains.
Collapse
|
17
|
Babakhani P. The impact of nanoparticle aggregation on their size exclusion during transport in porous media: One- and three-dimensional modelling investigations. Sci Rep 2019; 9:14071. [PMID: 31575953 PMCID: PMC6773746 DOI: 10.1038/s41598-019-50493-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 09/09/2019] [Indexed: 12/26/2022] Open
Abstract
Greater particle mobility in subsurface environments due to larger size, known as size exclusion, has been responsible for colloid-facilitated transport of groundwater contaminants. Although size exclusion is not expected for primary engineered nanoparticles (NP), they can grow in size due to aggregation, thereby undergoing size exclusion. To investigate this hypothesis, an accurate population balance modelling approach and other colloid transport theories, have been incorporated into a three-dimensional transport model, MT3D-USGS. Results show that incorporating aggregation into the transport model improves the predictivity of current theoretical and empirical approaches to NP deposition in porous media. Considering an artificial size-variable acceleration factor in the model, NP breakthrough curves display an earlier arrival when aggregation is included than without. Disregarding the acceleration factor, aggregation enhances NP mobility at regions close to the injection point at a field scale and causes their retention at greater distances through alteration of their diffusivities, secondary interaction-energy minima, and settling behaviour. This results in a change of residual concentration profiles from exponential for non-aggregating dispersions to non-monotonic for aggregating dispersions. Overall, aggregation, hitherto believed to hinder the migration of NP in subsurface porous media, may under certain physicochemical conditions enhance their mobilities and deliver them to further distances.
Collapse
Affiliation(s)
- Peyman Babakhani
- School of Engineering, University of Liverpool, Liverpool, Merseyside, L69 3GH, UK.
| |
Collapse
|