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Zhu Z, Kong Y, Yang H, Tian Y, Zhou X, Zhu Y, Fang Z, Zhang L, Tang S, Fan Y. Effects of Pretreatment and Polarization Shielding on EK-PRB of Fe/Mn/C-LDH for Remediation of Arsenic Contaminated Soils. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:325. [PMID: 36678078 PMCID: PMC9860780 DOI: 10.3390/nano13020325] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
In this study, coupling electrokinetic (EK) with the permeable reactive barriers (PRB) of Fe/Mn/C-LDH composite was applied for the remediation of arsenic-contaminated soils. By using self-made Fe/Mn/C-LDH materials as PRB filler, the effects of pretreatment and polarization shielding on EK-PRB of Fe/Mn/C-LDH for remediation of arsenic contaminated soils were investigated. For the pretreatment, phosphoric acid, phosphoric acid and water washing, and phosphate were adopted to reduce the influence of iron in soil. The addition of phosphate could effectively reduce the soil leaching toxicity concentration. The removal rate of the soil pretreated with phosphoric acid or phosphoric acid and water washing was better than with phosphate pretreatment. For the polarization shielding, circulating electrolyte, electrolyte type, anion and cation membranes, and the exchange of cathode and anode were investigated. The electrolyte circulates from the cathode chamber to the anode chamber through the peristaltic pump to control the pH value of the electrolyte, and the highest arsenic toxicity removal rate in the soil reaches 97.36%. The variation of total arsenic residue in soil using anion and cation membranes is the most regular. The total arsenic residue gradually decreases from cathode to anode. Electrode exchange can neutralize H+ and OH- produced by electrolyte, reduce the accumulation of soil cathode area, shield the reduction of repair efficiency caused by resistance polarization, enhance current, and improve the removal rate of arsenic in soil.
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Affiliation(s)
- Zongqiang Zhu
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
- The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin 541004, China
- Technical Innovation Center of Mine Geological Environmental Restoration Engineering in Southern Karst Area, Nanning 530022, China
| | - Yusong Kong
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Hongqu Yang
- Chongqing Hechuan Ecology and Environment Monitoring Station, Chongqing 401519, China
| | - Yan Tian
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Xiaobin Zhou
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
- The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin 541004, China
| | - Yinian Zhu
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
- The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin 541004, China
| | - Zhanqiang Fang
- School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China
| | - Lihao Zhang
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Shen Tang
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
| | - Yinming Fan
- Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004, China
- The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin 541004, China
- Technical Innovation Center of Mine Geological Environmental Restoration Engineering in Southern Karst Area, Nanning 530022, China
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Li Y, Wang X, Xiao Z, Liao G, Wang J, Li X, Tang Y, He C, Li L. Efficient removal of TBBPA with a Z-scheme BiVO 4-(rGO-Cu 2O) photocatalyst under sunlight irradiation. CHEMOSPHERE 2022; 308:136259. [PMID: 36057348 DOI: 10.1016/j.chemosphere.2022.136259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/16/2022] [Accepted: 08/27/2022] [Indexed: 05/12/2023]
Abstract
In this study, reduced graphene oxide (rGO) was used to fabricate a Z-scheme BiVO4-(rGO-Cu2O) photocatalyst for the degradation of Tetrabromobisphenol A (TBBPA) under sunlight irradiation. The photocatalyst was synthesized using a three-step method BiVO4-(rGO-Cu2O) photocatalyst with an rGO loading of 1% and (rGO-Cu2O) to BiVO4 ratio of 50% achieved the best degradation effect for TBBPA removal. Electron paramagnetic resonance spectroscopy (EPR) confirmed that the charge transfer path of BiVO4-(rGO-Cu2O) follows that of Z-scheme photocatalysts. Moreover, the addition of rGO increases the charge transfer efficiency. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to detect and analyze intermediate products, allowing the proposal of the main degradation pathway of TBBPA. Photogenerated electrons of BiVO4-(rGO-Cu2O) were then transferred into the conduction band of Cu2O. Cu2O is located in the surface layer, which has the most effective contact area with pollutants, and therefore has a good outcome for the photocatalytic reduction of TBBPA. Photogenerated electrons (e-) and hydroxyl radicals (∙OH) are the main factors affecting TBBPA degradation. The degradation process of TBBPA includes electron reduction debromination, hydroxylation, and β-cleavage. In our work, BiVO4-(rGO-Cu2O) was successfully synthesized to degrade TBBPA; this study brings forth a novel approach for the degradation of halogenated organic pollutants using a Z-scheme photocatalytic composite.
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Affiliation(s)
- Yaoyi Li
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China
| | - Xi Wang
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China.
| | - Zijun Xiao
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China
| | - Gaozu Liao
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China
| | - Jing Wang
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China.
| | - Xukai Li
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China
| | - Yiming Tang
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China
| | - Chun He
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology(Sun Yat-sen University) , China
| | - Laisheng Li
- Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Environment, South China Normal University, Higher Education Mega Center, Guangzhou, 510006, China; School of Environment, South China Normal University, Guangzhou, 510006, China; Guangdong Provincial Engineering Technology Research Center for Drinking Water Safety, Guangzhou, 510006, China; Guangdong Provincial Key Lab of Functional Materials for Environmental Protection, Guangzhou, 510006, China
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Wacławek S, Krawczyk K, Silvestri D, Padil VV, Řezanka M, Černík M, Jaroniec M. Cyclodextrin-based strategies for removal of persistent organic pollutants. Adv Colloid Interface Sci 2022; 310:102807. [DOI: 10.1016/j.cis.2022.102807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 10/19/2022] [Accepted: 10/28/2022] [Indexed: 11/08/2022]
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Abstract
Abstract
This paper evaluates the remediation of soil spiked with lindane using a combined treatment consisting of electrokinetic soil flushing (EKSF) with air stripping to elucidate the main processes occurring in the soil when electric fields of 0.75 V cm−1 and 1.50 V cm−1 are applied. The results demonstrate that lindane is efficiently transported to the anodic and cathodic wells using flushing fluids containing sodium dodecyl sulfate (SDS). Additionally, an important amount is volatilized and stripped with the injected air. In the cathodic well, lindane is rapidly transformed into other species because of the strongly alkaline media. These other species are also found in the portions of soil next to this well, confirming the efficient transport of chlorinated organics with SDS. After 14 days of operation, nearly 50% of the spiked lindane can be removed from the soil. Operation with large electric fields does not improve the performance of the treatment technology and results in lower current intensities and electro-osmotic fluxes and in higher evaporated water, despite the water content in the soil matrix, indicating the coexistence of multiple inputs in these processes.
Graphical abstract
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Zhang M, Feng M, Bai X, Liu L, Lin K, Li J. Chelating surfactant N-lauroyl ethylenediamine triacetate enhanced electrokinetic remediation of copper and decabromodiphenyl ether co-contaminated low permeability soil: Applicability analysis. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113888. [PMID: 34619584 DOI: 10.1016/j.jenvman.2021.113888] [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: 05/03/2021] [Revised: 09/23/2021] [Accepted: 09/29/2021] [Indexed: 06/13/2023]
Abstract
In this study, chelating surfactant N-lauroyl ethylenediamine triacetate (N-LED3A) was used as strengthening agent for electrokinetic (EK) remediation of copper (Cu) and decabromodiphenyl ether (BDE209) co-contaminated low permeability soil. The results indicated that negligible amount of N-LED3A would be adsorbed on the experimental soil. The synchronous elution efficiencies (SEEs) of Cu and BDE209 had reached 65.4% and 49.9%, respectively, when the concentration of N-LED3A was 4000 mg/L, and they kept almost unchanged as the concentration of N-LED3A further increased. Meanwhile, the optimal SEEs were obtained at the pH condition within 6-8. The removal efficiencies of Cu (55.3%-65.8%) and BDE209 (31.4%-46.4%) would be increased with the applied voltage gradient and concentration of N-LED3A. In addition, BDE209 and Cu contaminants were also detected in the catholyte and anolyte, respectively, and their concentrations still showed an uptrend by the end of the experiments. While in the control experiments, the removal efficiency of Cu was in the range of 18.2%-23.6%, and almost no BDE209 was migrated out. The electric current would be increased with N-LED3A concentration increased, further resulting in the enhancement of cumulative electro-osmotic flow (EOF). However, the increment of EOF was limited after an 8-day treatment due to the declined capacity of the soil water supply, and the removal efficiency of BDE209 did not change proportionally to the cumulative EOF as a consequence. The accumulated (21 days) energy consumption under the optimal operation conditions (voltage gradient 1 V/cm, N-LED3A 1 g/L) was 377.28 KWh/m3. Efficiently synchronous removal of BDE209 and Cu could be achieved by the N-LED3A enhanced EK technique, exhibiting a promising application potential in the organic pollutant and heavy metal co-contaminated soil remediation.
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Affiliation(s)
- Meng Zhang
- 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
| | - Meiyun Feng
- 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
| | - Xue Bai
- 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
| | - Lili 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
| | - 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.
| | - Jianan 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.
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Xiao J, Pang Z, Zhou S, Chu L, Rong L, Liu Y, Li J, Tian L. The mechanism of acid-washed zero-valent iron/activated carbon as permeable reactive barrier enhanced electrokinetic remediation of uranium-contaminated soil. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.116667] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Zhu X, Zhong Y, Wang H, Li D, Deng Y, Gao S, Peng P. Compound-specific carbon isotope analysis for mechanistic characterization of debromination of decabrominated diphenyl ether. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8758. [PMID: 32065465 DOI: 10.1002/rcm.8758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
RATIONALE Decabrominated diphenyl ether (BDE-209) is a notorious persistent organic pollutant widely found in the environment. Developing a compound-specific isotope analysis (CSIA) method is much needed in order to trace its transport and degradation processes and to evaluate the effectiveness of the remediation of BDE-209 in the environment. However, the conventional CSIA method, i.e. gas chromatography (GC) combustion isotope ratio mass spectrometry, is not appropriate for BDE-209 because of its high thermal instability and incomplete combustion. METHODS We developed a high-performance liquid chromatography (HPLC) method for the separation and purification of BDE-209 that prevents its thermal reactivity as occurred in prior GC-based methods. The δ13 C value of the purified BDE-209 was determined using offline elemental analyzer isotope ratio mass spectrometry (EA/IRMS). This two-step method was applied to determine the δ13 C values of BDE-209 in two commercial samples and to characterize carbon isotope fractionation associated with the debromination of BDE-209 via nanoscale zero-valent iron. RESULTS The mean values of daily δ13 C analyses of six replicates of a BDE-209 standard varied from -27.66‰ to -27.92‰, with a standard deviation ranging from 0.07‰ to 0.16‰, indicating a good reproducibility of EA/IRMS. The EA/IRMS analysis of the purified BDE-209 standard indicated no obvious isotope fractionation during the sample purification. The impurity content in commercial BDE-209 samples may contribute additional variation of the δ13 C values of BDE-209. The δ13 C values of BDE-209 gradually changed from -27.47 ± 0.37‰ to -24.59 ± 0.19‰ when 74% of the BDE-209 standard was degraded within 36 h. The estimated carbon isotope enrichment factor was -1.72 ± 0.18‰. CONCLUSIONS The two-step method based on HPLC and EA/IRMS avoids the thermal instability of BDE-209 in the traditional CSIA method. It offers a novel approach for elucidating the degradation mechanisms of BDE-209 in the environment and for source identification in contaminated sites.
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Affiliation(s)
- Xifen Zhu
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yin Zhong
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
| | - Heli Wang
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dan Li
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan, 523808, China
| | - Yirong Deng
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Guangdong Provincial Academy of Environmental Science, Guangdong Key Laboratory of Contaminated Sites Environmental Management and Remediation, Guangzhou, 510045, China
| | - Shutao Gao
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
| | - Ping'an Peng
- Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Organic Geochemistry, Guangzhou, 510640, China
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Wang L, Huang L, Xia H, Li H, Li X, Liu X. Application of a multi-electrode system with polyaniline auxiliary electrodes for electrokinetic remediation of chromium-contaminated soil. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Fernández MA, Silva OF, Vico RV, de Rossi RH. Complex systems that incorporate cyclodextrins to get materials for some specific applications. Carbohydr Res 2019; 480:12-34. [PMID: 31158527 DOI: 10.1016/j.carres.2019.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/06/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
Cyclodextrins (CDs) are a family of biodegradable cyclic hydrocarbons composed of α-(1,4) linked glucopyranose subunits, the more common containing 6, 7 or 8 glucose units are named α, β and γ-cyclodextrins respectively. Since the discovery of CDs, they have attracted interest among scientists and the first studies were about the properties of the native compounds and in particular their use as catalysts of organic reactions. Characteristics features of different types of cyclodextrins stimulated investigation in different areas of research, due to its non-toxic and non-inmunogenic properties and also to the development of an improved industrial production. In this way, many materials with important properties have been developed. This mini-review will focus on chemical systems that use cyclodextrins, whatever linked covalently or mediated by the non covalent interactions, to build complex systems developed mainly during the last five years.
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Affiliation(s)
- Mariana A Fernández
- Instituto de Investigaciones en Fisicoquímica de Córdoba, CONICET y Dpto. de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, X5000HUA, Córdoba, Argentina.
| | - O Fernando Silva
- Instituto de Investigaciones en Fisicoquímica de Córdoba, CONICET y Dpto. de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Raquel V Vico
- Instituto de Investigaciones en Fisicoquímica de Córdoba, CONICET y Dpto. de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Rita H de Rossi
- Instituto de Investigaciones en Fisicoquímica de Córdoba, CONICET y Dpto. de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, X5000HUA, Córdoba, Argentina
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Huang T, Liu L, Zhang S, Xu J. Evaluation of electrokinetics coupled with a reactive barrier of activated carbon loaded with a nanoscale zero-valent iron for selenite removal from contaminated soils. JOURNAL OF HAZARDOUS MATERIALS 2019; 368:104-114. [PMID: 30665105 DOI: 10.1016/j.jhazmat.2019.01.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 01/09/2019] [Accepted: 01/14/2019] [Indexed: 06/09/2023]
Abstract
The range between dietary deficient and toxic levels for selenium is quite narrow. In this study, the synergistic effects of electrokinetics (EK) and a permeable reactive barrier (PRB) on the reductive sequestration of Se(IV) oxyanions from spiked soils were investigated in detail. Activated charcoal (AC)-supported Fe(II) and nanoscale zero-valent iron (nZVI) were prepared as the PRB media for use in an electrolyzer. In aqueous equilibrium adsorption tests, the AC-supported nZVI medium had a higher adsorption capacity than that of the other adsorbents. The Se(IV) removal isotherms were well-fitted using the Langmuir model. The Se(IV) removal rates were accurately predicted by both pseudo-first- and pseudo-second-order kinetic models. For the coupled systems, a moderate increase in the number of PRBs and decrease in the PRB thickness in the electrolyzer enhanced the removal and catalytic recovery of Se(IV) from the spiked soil samples. A Se(VI) removal efficiency of approximately 95% and Se(VI) reduction efficiency of 90% were achieved in the optimized electrochemical system. The Se(IV) species were reduced to Se° and FeSe by the AC-supported nZVI regardless of the pH distribution. The experimental results provide guidance for the multichannel recovery of Se from abandoned ore tailings or solid wastes.
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Affiliation(s)
- Tao Huang
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, 215500, China.
| | - Longfei Liu
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, 215500, China
| | - Shuwen Zhang
- Nuclear Resources Engineering College, University of South China, 421001, China
| | - Jiaojiao Xu
- School of Chemistry and Materials Engineering, Changshu Institute of Technology, 215500, China
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Ghaeminia M, Mokhtarani N. Remediation of nitrate-contaminated groundwater by PRB-Electrokinetic integrated process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 222:234-241. [PMID: 29859463 DOI: 10.1016/j.jenvman.2018.05.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 05/14/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
Activated carbon is used as a reactive media in Permeable Reactive Barrier (PRB) for the removal of inorganic contaminants such as nitrate from groundwater. Since removal rate by this media decreases by time and due to the high costs of excavation and replacement of new media, the usage of activated carbon as an adsorbent in PRB is limited. The present study aimed to solve this defect by integrating electrokinetic process and PRB, using in-situ regeneration of activated carbon. This research was carried out on a laboratory scale using synthetically contaminated water and modified activated carbon as a reactive media in PRB. The effects of pH, nitrate concentration, carbon to sand ratio, and also electric gradient on the performance of the process were evaluated, and optimal conditions were determined, to increase the system longevity. According to the results, by applying an electric gradient of 1.25 V cm-1 to the PRB alone process in optimum operating condition (135 mg L-1 initial nitrate concentration, flow rate of 2.3 L min-1, pH = 6.8, and carbon to sand ratios of 1:1) the adsorbent capacity increased by 90%. Under these conditions, the integrated process could keep nitrate concentration in the effluent below the standard limit for about 111 h, while the PRB alone process could do the same job for about 59 h. Also, SEM analysis showed that by applying electrokinetic process, activated carbon was regenerated. Integration of electrokinetic process and PRB was also caused nitrate to transfer from activated carbon media into the soil layer above the system. This nitrate-rich soil has the potential for reuse in agricultural activities.
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Affiliation(s)
- Mahdyar Ghaeminia
- Civil and Environmental Engineering Faculty, Tarbiat Modares University, 1411713116 Tehran, Iran.
| | - Nader Mokhtarani
- Civil and Environmental Engineering Faculty, Tarbiat Modares University, 1411713116 Tehran, Iran.
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