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Liu J, Liu A, Guo J, Zhou T, Zhang WX. Enhanced aggregation and sedimentation of nanoscale zero-valent iron (nZVI) with polyacrylamide modification. CHEMOSPHERE 2021; 263:127875. [PMID: 32835968 DOI: 10.1016/j.chemosphere.2020.127875] [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: 07/02/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
Nanoscale zero-valent iron (nZVI) settled slowly and incompletely in a nano-iron reactor (NIR) in wastewater treatment, and the effluent quality and processing capacity of nZVI were degenerated. Herein, three types of polyacrylamide (PAM), anionic-APAM (nZVIAPAM), cationic-CPAM (nZVICPAM), and nonionic-NPAM (nZVINPAM)) were applied to modify the nZVI (nZVIPAM), which were proved to enhance aggregation and sedimentation in the gravity settling clarifier of NIR. PAM modification lead to aggregate by forming large agglomerates. The median sizes of aggregates were 32, 194, 168 and 133 μm respectively for nZVI, nZVICPAM, nZVINPAM, and nZVIAPAM. Under quiescent conditions, bare nZVI needed 5 min to reach sedimentation equilibrium, while nZVIPAM just within 1 min nZVICPAM settled more quickly and completely than nZVINPAM and nZVIAPAM. The Fe concentration in the dynamic flow NIR effluent could keep a low level for 8 h for nZVIPAM, while bare nZVI for 6 h. Iron concentration was 3.11, 0.037, 0.93, and 1.20 mg·L-1 for nZVI, nZVICPAM, nZVINPAM, and nZVIAPAM after 8-h-reaction. Meanwhile, the reactivity of nZVIPAM was kept much longer for lead removal in the NIR. Results demonstrated PAM modifications (especially CPAM) provided a reliable solution for nZVI aggregation and sedimentation in wastewater treatment.
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Affiliation(s)
- Jing Liu
- State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Airong Liu
- State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
| | - Jie Guo
- State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Tao Zhou
- State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Wei-Xian Zhang
- State Key Laboratory for Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
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2
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Li C, Lu Q, Zhan C, Tariq M, Huang K, Liu F, Zhu F, Liu G, Cui C, Lin K. Efficient novel amphiphilic double shells layer coupled with nanoscale zero-valent composite for the degradation of trichloroethylene. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 659:821-827. [PMID: 31096412 DOI: 10.1016/j.scitotenv.2018.12.301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/20/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
An efficient novel amphiphilic material composed of core-double shells nanocomposite (CDSN) with nanoscale zero-valent iron (NZVI) as the core and PS100-b-PAA16 as inner shell and chitosan as outmost shell has been synthesized successfully. Its application to remove the trichloroethylene (TCE) in stimulated TCE solution with 7.3 ± 0.3 mg/L dissolved oxygen was investigated. The results showed that CDSN after exposure to air for a month could still remove 92.6% of TCE as compared to 61.5% removal rate of NZVI in 360 min (the gram ratio of material: TCE equals to 10:1), exhibiting the great oxidation resistance performance. Specifically, dynamic research of the total removal divided into adsorption by shell layer and degradation by reducibility of NZVI at a predetermined interval was engaged to understand the complete mass transfer process of TCE. The results revealed that CDSN adsorbed 1.5 to 2 folds time TCE as compared to NZVI in the same initial pH = 8.5 aqueous solution. Importantly, CDSN could sustain fixed reactivity to remove about 94.8% of TCE from the start to end. NZVI exhibited greater removal capacity in first 180 min, but later it lost the reducibility and finial removal rate was 89%. The selective adsorption to protonated CDSN was strengthened to increase the removal of TCE at pH 3.5 while NZVI had a worse removal in pH 3.5 performance than pH 8.5.
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Affiliation(s)
- Can Li
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qiang Lu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Cong Zhan
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Muhammad Tariq
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Kai Huang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Fuwen Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Fei Zhu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Guanhong Liu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Changzheng Cui
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Kuangfei Lin
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
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Lu H, Wen C, Gao S, Dong Y, Zhang M, Li B, Hu W, Dong J. Incorporation of nanoscale zero-valent iron particles in monodisperse mesoporous silica nanospheres: Characterization, reactivity, transport in porous media. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.05.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Phenrat T, Schoenfelder D, Kirschling TL, Tilton RD, Lowry GV. Adsorbed poly(aspartate) coating limits the adverse effects of dissolved groundwater solutes on Fe 0 nanoparticle reactivity with trichloroethylene. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:7157-7169. [PMID: 26233743 DOI: 10.1007/s11356-015-5092-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/16/2015] [Indexed: 06/04/2023]
Abstract
For in situ groundwater remediation, polyelectrolyte-modified nanoscale zerovalent iron particles (NZVIs) have to be delivered into the subsurface, where they degrade pollutants such as trichloroethylene (TCE). The effect of groundwater organic and ionic solutes on TCE dechlorination using polyelectrolyte-modified NZVIs is unexplored, but is required for an effective remediation design. This study evaluates the TCE dechlorination rate and reaction by-products using poly(aspartate) (PAP)-modified and bare NZVIs in groundwater samples from actual TCE-contaminated sites in Florida, South Carolina, and Michigan. The effects of groundwater solutes on short- and intermediate-term dechlorination rates were evaluated. An adsorbed PAP layer on the NZVIs appeared to limit the adverse effect of groundwater solutes on the TCE dechlorination rate in the first TCE dechlorination cycle (short-term effect). Presumably, the pre-adsorption of PAP "trains" and the Donnan potential in the adsorbed PAP layer prevented groundwater solutes from further blocking NZVI reactive sites, which appeared to substantially decrease the TCE dechlorination rate of bare NZVIs. In the second and third TCE dechlorination cycles (intermediate-term effect), TCE dechlorination rates using PAP-modified NZVIs increased substantially (~100 and 200%, respectively, from the rate of the first spike). The desorption of PAP from the surface of NZVIs over time due to salt-induced desorption is hypothesized to restore NZVI reactivity with TCE. This study suggests that NZVI surface modification with small, charged macromolecules, such as PAP, helps to restore NZVI reactivity due to gradual PAP desorption in groundwater.
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Affiliation(s)
- Tanapon Phenrat
- Research Unit for Integrated Natural Resources Remediation and Reclamation (IN3R), Department of Civil Engineering, Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand.
- Center of Excellence for Sustainability of Health, Environment and Industry (SHEI), Faculty of Engineering, Naresuan University, Phitsanulok, 65000, Thailand.
| | - Daniel Schoenfelder
- Center for Environmental Implications of Nanotechnology (CEINT) and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
| | - Teresa L Kirschling
- Center for Environmental Implications of Nanotechnology (CEINT) and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
| | - Robert D Tilton
- Center for Environmental Implications of Nanotechnology (CEINT) and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA
| | - Gregory V Lowry
- Center for Environmental Implications of Nanotechnology (CEINT) and Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA.
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213-3890, USA.
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Fan D, Lan Y, Tratnyek PG, Johnson RL, Filip J, O'Carroll DM, Nunez Garcia A, Agrawal A. Sulfidation of Iron-Based Materials: A Review of Processes and Implications for Water Treatment and Remediation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13070-13085. [PMID: 29035566 DOI: 10.1021/acs.est.7b04177] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Iron-based materials used in water treatment and groundwater remediation-especially micro- and nanosized zerovalent iron (nZVI)-can be more effective when modified with lower-valent forms of sulfur (i.e., "sulfidated"). Controlled sulfidation for this purpose (using sulfide, dithionite, etc.) is the main topic of this review, but insights are derived by comparison with related and comparatively well-characterized processes such as corrosion of iron in sulfidic waters and abiotic natural attenuation by iron sulfide minerals. Material characterization shows that varying sulfidation protocols (e.g., concerted or sequential) and key operational variables (e.g., S/Fe ratio and sulfidation duration) result in materials with structures and morphologies ranging from core-shell to multiphase. A meta-analysis of available kinetic data for dechlorination under anoxic conditions, shows that sulfidation usually increases dechlorination rates, and simultaneously hydrogen production is suppressed. Therefore, sulfidation can greatly improve the efficiency of utilization of reducing equivalents for contaminant removal. This benefit is most likely due to inhibited corrosion as a result of sulfidation. Sulfidation may also favor desirable pathways of contaminant removal, such as (i) dechlorination by reductive elimination rather than hydrogenolysis and (ii) sequestration of metals as sulfides that could be resistant to reoxidation. Under oxic conditions, sulfidation is shown to enhance heterogeneous catalytic oxidation of contaminants. These net effects of sulfidation on contaminant removal by iron-based materials may substantially improve their practical utility for water treatment and remediation of contaminated groundwater.
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Affiliation(s)
- Dimin Fan
- Oak Ridge Institute for Science and Education (ORISE) Fellow, Office of Superfund Remediation and Technology Innovation, U.S. Environmental Protection Agency, 2777 Crystal Drive, Arlington, Virginia 22202, United States
| | - Ying Lan
- OHSU-PSU School of Public Health, Oregon Health & Science University , 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Paul G Tratnyek
- OHSU-PSU School of Public Health, Oregon Health & Science University , 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Richard L Johnson
- OHSU-PSU School of Public Health, Oregon Health & Science University , 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Jan Filip
- Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc , Šlechtitelů 27, CZ-78371 Olomouc, Czech Republic
| | - Denis M O'Carroll
- School of Civil and Environmental Engineering, Connected Water Initiative, University of New South Wales , Manly Vale, New South Wales 2093, Australia
| | - Ariel Nunez Garcia
- Department of Civil and Environmental Engineering, Western University , 1151 Richmond St., London, Ontario Canada
| | - Abinash Agrawal
- Department of Earth and Environmental Sciences, Wright State University, Wright State University , 3640 Colonel Glenn Highway, Dayton, Ohio 45435, United States
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Kim HS, Ahn JY, Kim C, Lee S, Hwang I. Effect of anions and humic acid on the performance of nanoscale zero-valent iron particles coated with polyacrylic acid. CHEMOSPHERE 2014; 113:93-100. [PMID: 25065795 DOI: 10.1016/j.chemosphere.2014.04.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 04/14/2014] [Accepted: 04/16/2014] [Indexed: 06/03/2023]
Abstract
Effects of anions (NO3(-), HCO3(-), Cl(-), SO4(2-)) and humic acid on the reactivity and core/shell chemistries of polyacrylic acid-coated nanoscale zero-valent iron (PAA-NZVI) and inorganically modified NZVI (INORG-NZVI) particles were investigated. The reactivity tests under various ion concentrations (0.2-30mN) revealed the existence of a favorable molar ratio of anion/NZVI that increased the reactivity of NZVI particles. The presence of a relatively small amount of humic acid (0.5mgL(-1)) substantially decreased the INORG-NZVI reactivity by 76%, whereas the reactivity of PAA-NZVI decreased only by 12%. The XRD and TEM results supported the role of the PAA coating of PAA-NZVI in impeding the oxidation of the Fe(0) core by groundwater solutes. This protective role provided by the organic coating also resulted in a 2.3-fold increase in the trichloroethylene (TCE) reduction capacity of PAA-NZVI compared to that of INORG-NZVI in the presence of anions/humic acid. Ethylene and ethane were simultaneously produced as the major reduction products of TCE in both NZVI systems, suggesting that a hydrodechlorination occurred without the aid of metallic catalysts. The PAA coating, originally designed to improve the mobility of NZVI, enhanced TCE degradation performances of NZVI in the presence of anions and humic acid.
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Affiliation(s)
- Hong-Seok Kim
- Research & Development Division, Hyundai Engineering & Construction Co., Ltd., 17-5, Mabukno 240-gil, Giheung-gu, Yongin-si, Gyeonggi-do 446-912, Republic of Korea
| | - Jun-Young Ahn
- School of Civil and Environmental Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea
| | - Cheolyong Kim
- School of Civil and Environmental Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea
| | - Seockheon Lee
- Center for Water Resource Cycle, Korea Institute of Science and Technology, Hwarangdo 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
| | - Inseong Hwang
- School of Civil and Environmental Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
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Tesh SJ, Scott TB. Nano-composites for water remediation: a review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:6056-68. [PMID: 25069835 DOI: 10.1002/adma.201401376] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/19/2014] [Indexed: 05/04/2023]
Abstract
As global populations continue to increase, the pressure on water supplies will inevitably intensify. Consequently the international need for more efficient and cost effective water remediation technologies will also rise. The introduction of nano-technology into the industry may represent a significant advancement and zero-valent iron nano-particles (INPs) have been thoroughly studied for potential remediation applications. However, the application of water dispersed INP suspensions is limited and somewhat contentious on the grounds of safety, whilst INP reaction mechanisms, transport properties and ecotoxicity are areas still under investigation. Theoretically, the development of nano-composites containing INPs to overcome these issues provides the logical next step for developing nano-materials that are better suited to wide application across the water industry. This review provides an overview of the range of static, bulk nano-composites containing INPs being developed, whilst highlighting the limitations of individual solutions, overall classes of technology, and lack of comparative testing for nano-composites. The review discusses what further developments are needed to optimize nano-composite water remediation systems to subsequently achieve commercial maturity.
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Affiliation(s)
- Sarah J Tesh
- Interface Analysis Centre, School of Physics, University of Bristol, H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
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Wei J, Qian Y, Liu W, Wang L, Ge Y, Zhang J, Yu J, Ma X. Effects of particle composition and environmental parameters on catalytic hydrodechlorination of trichloroethylene by nanoscale bimetallic Ni-Fe. J Environ Sci (China) 2014; 26:1162-1170. [PMID: 25079647 DOI: 10.1016/s1001-0742(13)60506-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 08/19/2013] [Accepted: 09/06/2013] [Indexed: 06/03/2023]
Abstract
Catalytic nickel was successfully incorporated into nanoscale iron to enhance its dechlorination efficiency for trichloroethylene (TCE), one of the most commonly detected chlorinated organic compounds in groundwater. Ethane was the predominant product. The greatest dechlorination efficiency was achieved at 22 molar percent of nickel. This nanoscale Ni-Fe is poorly ordered and inhomogeneous; iron dissolution occurred whereas nickel was relatively stable during the 24-hr reaction. The morphological characterization provided significant new insights on the mechanism of catalytic hydrodechlorination by bimetallic nanoparticles. TCE degradation and ethane production rates were greatly affected by environmental parameters such as solution pH, temperature and common groundwater ions. Both rate constants decreased and then increased over the pH range of 6.5 to 8.0, with the minimum value occurring at pH 7.5. TCE degradation rate constant showed an increasing trend over the temperature range of 10 to 25°C. However, ethane production rate constant increased and then decreased over the range, with the maximum value occurring at 20°C. Most salts in the solution appeared to enhance the reaction in the first half hour but overall they displayed an inhibitory effect. Combined ions showed a similar effect as individual salts.
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Affiliation(s)
- Jianjun Wei
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yajing Qian
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wenjuan Liu
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lutao Wang
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yijie Ge
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianghao Zhang
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jiang Yu
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xingmao Ma
- Department of Civil and Environmental Engineering, Southern Illinois University Carbondale, Carbondale, IL 62901, United States.
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Wang X, Yang J, Zhu M, Li F. Characterization and regeneration of Pd/Fe nanoparticles immobilized in modified PVDF membrane. J Taiwan Inst Chem Eng 2013. [DOI: 10.1016/j.jtice.2012.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Wang X, Zhu M, Liu H, Ma J, Li F. Modification of Pd-Fe nanoparticles for catalytic dechlorination of 2,4-dichlorophenol. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 449:157-167. [PMID: 23425792 DOI: 10.1016/j.scitotenv.2013.01.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/01/2013] [Accepted: 01/01/2013] [Indexed: 06/01/2023]
Abstract
To reveal how different dispersants influence the dispersity and physicochemical properties of palladium/iron nanoparticles (Pd/Fe NPs), we modified Pd/Fe NPs with poly(methylmethacrylate) (PMMA), polyacrylic acid (PAA) and cetyltrimethylammonium bromide (CTAB) respectively and obtained three hybrid NPs denoted M-Pd/Fe NPs, A-Pd/Fe NPs and C-Pd/Fe NPs. The physical properties of the three hybrid Pd/Fe NPs were studied, together with their behaviors in the room-temperature dechlorination in aqueous solution of 2,4-dichlorophenol (2,4-DCP). Dispersant effects of the three dispersants were observed, as well as changes in the properties of resulted Pd/Fe NPs. The pristine Pd/Fe NPs experienced more severe oxidation than A-Pd/Fe NPs, while there was no evidence for the presence of oxidation phase of M-Pd/Fe NPs and C-Pd/Fe NPs. Degradation results showed that compared with pristine Pd/Fe NPs, the catalytic dechlorination efficiency of 2,4-DCP with modified Pd/Fe NPs increased by 23%-58% within a given reaction period of 20 min. The role of dispersants themselves in dechlorination properties of Pd/Fe NPs is more significant than that of volume ratio of PAA to water, weight ratio of PMMA to anisole and volume ratio of water to ethanol in determining the properties of A-Pd/Fe, M-Pd/Fe and C-Pd/Fe NPs, respectively. Studies on the kinetics of 2,4-DCP reacted with Pd/Fe NPs in our cases implied that their behaviors didn't match the first- or pseudo-first-order kinetics: because the presence of oxidation phases on the surface of pristine Pd/Fe NPs and the dispersants on the surface of NPs could influence the diffusion of 2,4-DCP onto reactive sites, thus affecting the whole degradation process. So, an innovatively revised kinetics was proposed in the study for considering the effects of oxidation phases and the dispersants.
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Affiliation(s)
- Xiangyu Wang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
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Velimirovic M, Chen H, Simons Q, Bastiaens L. Reactivity recovery of guar gum coupled mZVI by means of enzymatic breakdown and rinsing. JOURNAL OF CONTAMINANT HYDROLOGY 2012; 142-143:1-10. [PMID: 23047137 DOI: 10.1016/j.jconhyd.2012.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 09/05/2012] [Accepted: 09/10/2012] [Indexed: 06/01/2023]
Abstract
Microscale zerovalent iron (mZVI) reduces chlorinated aliphatic hydrocarbons (CAHs) to harmless compounds, but the sedimentation of the mZVI particles in the injection fluid limits the injectability of the particles during field applications. In this study, mZVI particles in suspension were stabilized by green polymer guar gum, which had a positive impact on mZVI stability, but decreased the reactivity of the particles towards CAHs by 1 to 8 times. Guar gum (GG) was found to adsorb onto the mZVI surface, inhibiting contact between the chlorinated compounds and the reactive iron surface. Indications were found for intermolecular hydrogen bonding between mZVI and the guar gum. Subsequent addition of commercially available enzymes resulted in the cleavage of the polysaccharide guar gum into lower molecular fragments, but not in improved reactivity. The reactivity recovery of guar gum coupled mZVI was recovered after intensive rinsing of the iron particles, removing the guar gum fragments from the particles. Overall, this study shows that CAHs can be treated efficiently by guar gum stabilized mZVI after reactivation by means of enzymatic breakdown and rinsing.
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Affiliation(s)
- Milica Velimirovic
- Flemish Institute for Technological Research, VITO, Boeretang 200, 2400 Mol, Belgium.
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Tratnyek PG, Salter-Blanc AJ, Nurmi JT, Amonette JE, Liu J, Wang C, Dohnalkova A, Baer DR. Reactivity of Zerovalent Metals in Aquatic Media: Effects of Organic Surface Coatings. ACS SYMPOSIUM SERIES 2011. [DOI: 10.1021/bk-2011-1071.ch018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Paul G. Tratnyek
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Alexandra J. Salter-Blanc
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - James T. Nurmi
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - James E. Amonette
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Juan Liu
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Chongmin Wang
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Alice Dohnalkova
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
| | - Donald R. Baer
- Division of Environmental and Biomolecular Systems, Oregon Health & Science University, 20000 NW Walker Road, Beaverton, OR 97006
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352
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