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Acheampong E, Lee ES. Low-temperature slow-release permanganate gel for groundwater remediation: Dynamics in saturated porous media. CHEMOSPHERE 2024; 363:142716. [PMID: 38945223 DOI: 10.1016/j.chemosphere.2024.142716] [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: 03/20/2024] [Revised: 06/21/2024] [Accepted: 06/26/2024] [Indexed: 07/02/2024]
Abstract
Due to its adverse health and environmental impacts, groundwater contamination by toxic organic compounds such as chlorinated solvents is a global concern. The slow-release permanganate gel (SRP-G) is a mixture of potassium permanganate (KMnO4) and colloidal silica solution. The SRP-G is designed to radially spread after injection via wells, gelate in situ to form gel barriers containing permanganate (MnO4-), and slowly release MnO4- to treat plumes of chlorinated solvents in groundwater. This study aimed to characterize the effects of temperature on the dynamics of SRP-G in saturated porous media. In gelation batch tests, the viscosity of ambient-temperature (24 °C) SRP-G with 30 g/L-KMnO4 was 21 cP at 70 min, 134 cP at 176 min, and peaked at 946 cP to solidification at 229 min. The viscosity of low-temperature (4 °C) SRP-G with 30 g/L-KMnO4 was 71 cP at 273 min, 402 cP at 392 min, and peaked at 818 cP to solidification at 485 min. A similar pattern, e.g., increased gelation lag time with low-temperature SRP-G, was observed for SRP-Gs with 40 g/L, 50 g/L, and 60 g/L KMnO4. In flow-through tests using a glass column filled with saturated sands, injection rates, spreading rates, and release durations were 0.6 mL/min, 46 mm/min, and 33 h for KMnO4(aq), 0.2 mL/min, 2 mm/min, and 38 h for ambient-temperature SRP-G, and 0.4 mL/min, 16 mm/min, and 115 h for low-temperature SRP-G, respectively. These results indicated that the injectability, injection rate, and gelation lag time of SRP-G and the size, release rate, and release duration of MnO4- gel barriers can be increased at low temperatures. The low-temperature SRP-G scheme can be useful for treating large or dilute dissolved plumes of chlorinated solvents or other pollutants in groundwater.
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Affiliation(s)
- Emmanuel Acheampong
- Department of Earth and Environmental Geosciences, Ohio University, Athens, OH, 45701, USA
| | - Eung Seok Lee
- Department of Earth and Environmental Geosciences, Ohio University, Athens, OH, 45701, USA.
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Ogundare O, Tick GR, Esfahani MR, Akyol NH, Zhang Y. Laboratory-scale characterization of slow-release permanganate gel (SRP-G) for the in-situ treatment of chlorinated-solvent groundwater plumes. CHEMOSPHERE 2024; 360:142392. [PMID: 38777195 DOI: 10.1016/j.chemosphere.2024.142392] [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: 04/11/2024] [Revised: 05/13/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
Significant challenges remain for the remediation of chlorinated-solvent plumes in groundwater, such as trichloroethene (TCE) and tetrachloroethene (PCE). A novel slow-release permanganate gel (SRP-G) technique may show promise for the in-situ treatment (remediation) of chlorinated contaminant plumes in groundwater. A series of laboratory experiments were conducted to characterize the primary physical factors that influence SRP-G gelation processes to optimize SRP-G performance for plume treatment. Specifically, experiments were conducted to quantify gel zeta potential, particle size distribution, and viscosity to determine SRP-G gelation characteristics and processes. These experiments tested various concentrations of two SRP-G amendment solutions (NaMnO4 and KMnO4) prepared with 30-wt.% and 50-wt.% colloidal silica to determine such influences on zeta potential, particle size distribution, and viscosity. The results of this study show that SRP-G solutions with low zeta potential and relatively high pH favor more rapid SRP-G gelation. The concomitant interaction of the predominantly negatively charged colloidal silica particles and the positively charged dissociated cations (Na+ and K+) in the SRP-G solution had the effect of stabilizing charge imbalance via attraction of particles and thereby inducing a greater influence on the gelation process. Gel particle size distribution and changes in viscosity had a significant influence on SRP-G solution gelation. The addition of permanganate (NaMnO4 or KMnO4) increased the average particle size distribution and the viscosity of the SRP-G solution and decreased the overall gelation time. SRP-G amendments (NaMnO4 or KMnO4) prepared with 50-wt.% colloidal silica showed more effective gelation (and reduced gelation time) compared to SRP-G amendments prepared with 30-wt.% colloidal silica. Under the conditions of these experiments, it was determined that both the 7-wt.% NaMnO4 solution and 90 mg/L KMnO4 solution using 50-wt.% colloidal silica would be the optimal injection SRP-G solution concentrations for this in-situ treatment technique.
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Affiliation(s)
- Ojo Ogundare
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA.
| | - Geoffrey R Tick
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA; Santa Clara Valley Water District, Groundwater Management Unit, San Jose, CA, 95118, USA.
| | - Milad Rabbani Esfahani
- Department of Chemical and Biological Engineering, University of Alabama, Tuscaloosa, AL, 35487, USA.
| | - Nihat Hakan Akyol
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA; Department of Geological Engineering, Kocaeli University, 41380, Turkey.
| | - Yong Zhang
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA.
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Zhao S, Wang J, Zhu W. Controlled-Release Materials for Remediation of Trichloroethylene Contamination in Groundwater. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7045. [PMID: 37959642 PMCID: PMC10650286 DOI: 10.3390/ma16217045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/01/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023]
Abstract
Groundwater contamination by trichloroethylene (TCE) presents a pressing environmental challenge with far-reaching consequences. Traditional remediation methods have shown limitations in effectively addressing TCE contamination. This study reviews the limitations of conventional remediation techniques and investigates the application of oxidant-based controlled-release materials, including encapsulated, loaded, and gel-based potassium permanganate since the year 2000. Additionally, it examines reductant controlled-release materials and electron donor-release materials such as tetrabutyl orthosilicate (TBOS) and polyhydroxybutyrate (PHB). The findings suggest that controlled-release materials offer a promising avenue for enhancing TCE degradation and promoting groundwater restoration. This study concludes by highlighting the future research directions and the potential of controlled-release materials in addressing TCE contamination challenges.
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Affiliation(s)
- Shan Zhao
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China;
- College of Civil Engineering, Tongji University, Shanghai 200092, China
| | - Jianhua Wang
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China;
| | - Wenjin Zhu
- School of Civil and Ocean Engineering, Jiangsu Ocean University, Lianyungang 222005, China
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Xu X, Wan S, Xia F, Han X, Deng S, Xiao H, Jiang Y, Liu H, Yang Y. Preparation and properties of the persulfate gel materials and application for the remediation of 2,4-dinitrotoluene contaminated groundwater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:157023. [PMID: 35772545 DOI: 10.1016/j.scitotenv.2022.157023] [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: 03/17/2022] [Revised: 06/20/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
This study aims to develop persulfate new gel sustaining-release material (PGSR) and gelatin-gel sustaining-release material (G-PGSR) that can be injected into aquifers and slowly release S2O82- to groundwater. Compatibility and miscibility of colloidal silica gels and gelatin with S2O82- were tested. Morphologies of the as-prepared PGSR and G-PGSR were observed by scanning electron microscope (SEM) and Fourier transform infrared spectrometer (FT-IR). Release characteristics of PGSR containing variable persulfate concentrations (from 1.25 wt% to 5 wt%), silica sol (from 30 wt% to 40 wt%), and gelatin (from 0.5 wt% to 2.0 wt%) were monitored. Viscosities of PGSR solution increased from 5 to 112 cP with increasing silica sol from 30 wt% to 40 wt% during the first 10 min. Viscosities of PGSR solution in 40 wt% silica sol increased to 346 cP within the 30 min and rapidly increased to 8000 cP within the next 30 min followed by the gelation phase. Gelation rates of the PGSR solution increased with increased persulfate concentrations from 1.25 wt% to 5.0 wt%. The maximum release rates achieved at 5 h in G-PGSR were 1.98 mg of S2O82- per min similar to that in PGSR. The release persulfate concentrations in G-PGSR suggested that gelatin and colloidal silica were both compatible and miscible with S2O82-. Meanwhile, the PGSR exhibits a characteristic two-phase increase in viscosity with increased silica sol concentrations, persulfate concentrations, and gelatin concentrations. Compared with the persulfate only system, the degradation efficiency of 2,4-dinitrotoluene (2,4-DNT) was achieved 91.5 % within 3 h, while 78.6 % and 66.9 % degradation efficiency were shown in PGSR and G-PGSR, respectively. The PGSR and G-PGSR both could create persistent oxidation degradation of 2,4-DNT. Results suggested that colloidal silica and gelatin could be used to create PGSR and G-PGSR for persistent oxidation in groundwater remediation.
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Affiliation(s)
- Xiangjian Xu
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Shuoyang Wan
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Fu Xia
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Xu Han
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Sheng Deng
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Han Xiao
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Yonghai Jiang
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Hui Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
| | - Yu Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
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Chang YC, Chen KF, Chen TY, Chen HH, Chen WY, Mao YC. Development of novel persulfate tablets for passive trichloroethylene (TCE)-contaminated groundwater remediation. CHEMOSPHERE 2022; 295:133906. [PMID: 35143855 DOI: 10.1016/j.chemosphere.2022.133906] [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: 06/30/2021] [Revised: 11/01/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
In this study, a biodegradable binder, hydroxypropyl methyl cellulose (HPMC), was used for the first time to mix with persulfate powder for developing novel persulfate-releasing tablets to remediate trichloroethylene (TCE)-contaminated groundwater. To obtain feasible parameters for the preparation of persulfate tablets, different pressures, HPMC/tablet mass ratios, and persulfate dosages were evaluated. The results showed that the persulfate tablet released 2868 mg-persulfate/day for 12 days under the optimal manufacturing parameters of HPMC/tablet mass ratio of 0.5 and pressure of 4.90 × 108 N/m2. Persulfate diffusion and gel layer erosion were dominant mechanisms for controlling the persulfate released in water. The persulfate release time and rate can be controlled by adjusting the persulfate dosage at the optimal HPMC/tablet ratio. In the column experiment, TCE with an initial concentration of 70 mg/L reached 55% removal efficiency by the tablet, which showed that the developed tablet was capable of degrading highly concentrated TCE. The results of electron spin resonance (ESR) spectroscopy showed that both SO4-· and ·OH were responsible for the oxidation of TCE. During 150 days of incubation, the biodegrading efficiency of HPMC by microbes in soil and activated sludge was 67% and 80%, respectively, under aerobic conditions, while 58% of HPMC was removed by soil bacteria under anaerobic conditions. The results showed that persulfate tablets could be used as a passive groundwater remediation system. There is no waste generated after persulfate is completely released during groundwater remediation. The developed persulfate tablets are environmentally friendly and meet the green remediation aspect.
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Affiliation(s)
- Yu-Chen Chang
- Department of Civil Engineering, National Chi Nan University, Puli, Nantou, 545301, Taiwan
| | - Ku-Fan Chen
- Department of Civil Engineering, National Chi Nan University, Puli, Nantou, 545301, Taiwan.
| | - Ting-Yu Chen
- Department of Landscape Architecture, National Chin-Yi University of Technology, Taiping, Taichung, 411030, Taiwan
| | - Hung-Hsiang Chen
- Department of Civil Engineering, National Chi Nan University, Puli, Nantou, 545301, Taiwan
| | - Wei-Yu Chen
- Department of Civil Engineering, National Chi Nan University, Puli, Nantou, 545301, Taiwan
| | - Ying-Chih Mao
- Department of Civil Engineering, National Chi Nan University, Puli, Nantou, 545301, Taiwan
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Optimization and Analysis of a Slow-Release Permanganate Gel for Groundwater Remediation in Porous and Low-Permeability Media. WATER 2021. [DOI: 10.3390/w13060755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dense nonaqueous phase liquids (DNAPLs) like trichloroethylene (TCE) serve as the most common form of groundwater pollution in the world. Potassium permanganate (KMnO4) is a strong oxidant that can quickly destroy DNAPLs into innocuous products. Slow-release permanganate gel (SRPG), a mixture of colloidal silica (CS) and KMnO4, has been recently developed as novel treatment option for dilute and large plumes of DNAPLs in groundwater. The objective of this study was to characterize and optimize gelling and release properties of a SRPG solution in saturated porous media. It was hypothesized that CS and KMnO4 content of the SRPG constrain gelation and release duration. Batch and column tests showed that gelation could be delayed through manipulation of the KMnO4 content. In column tests, silica content had little effect on the gelation lag stage and release rate but influenced duration of permanganate release. Flow tank tests comparing Bindzil 1440 (B-40) SRPGs with pure KMnO4 solutions under varying media conditions demonstrated that the presence of CS enhanced lateral spread and prolonged release duration of the oxidant.
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Yeum Y, Han K, Kang JH, Kim DW, Park CW, Kwon S, Kim Y. Production, characterization, and evaluation of two types of slow-releasing carbon source tablets for in-situ heterotrophic nitrate denitrification in aquifers. CHEMOSPHERE 2020; 260:127478. [PMID: 32683022 DOI: 10.1016/j.chemosphere.2020.127478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/02/2020] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
Slow-releasing carbon source tablets were manufactured for an in-situ biological denitrification system. The average zero-order nitrate degradation rates seen, from highest to lowest, were in microcosms to which lactate, fumarate, propionate, and formate had been added. Fumarate was approximately 80% cheaper than lactate, and consequently was determined to be the most optimal slow-releasing carbon source in tablet form. The slow-releasing precipitating tablet (SRPT) and slow-releasing floating tablet (SRFT) were manufactured with hydroxypropyl methylcellulose (HPMC) as the agent of release control, microcrystalline cellulose pH 101 (MCC 101) as the binder, #8 sand as the precipitation agent, and calcium carbonate and citric acid as floating agents. Fourier transform infrared spectroscopy and powder X-ray diffraction indicated that the crystal arrangement in the SRPTs and SRFTs was maintained and ordered in a manner similar to raw excipients. SRFTs floated in water within 30 min and remained so for 5 d due to the buoyancy of carbon dioxide. The carbon source release rate was proportional to the quantity of HPMC added. The longevities of SRPT with 300 mg of HPMC and SRFT with 400 mg of HPMC were 25.4 d and 37.3 d, respectively. This study observed that SRPT and SRFT were manufactured effectively and are suitable for in-situ slow-releasing biological systems.
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Affiliation(s)
- Yuhoon Yeum
- Program in Environmental Technology and Policy, Korea University, Sejong 30019, Republic of Korea
| | - Kyungjin Han
- Department of Environmental Engineering, Korea University, Sejong 30019, Republic of Korea
| | - Ji-Hyun Kang
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Republic of Korea
| | - Dong-Wook Kim
- Department of Pharmaceutical Engineering, Cheongju University, Cheongju 28503, Republic of Korea
| | - Chun-Woong Park
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Republic of Korea
| | - Sooyoul Kwon
- Department of Environmental Health, Korea National Open University, Seoul 03087, Republic of Korea
| | - Young Kim
- Program in Environmental Technology and Policy, Korea University, Sejong 30019, Republic of Korea; Department of Environmental Engineering, Korea University, Sejong 30019, Republic of Korea.
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Ma Y, Feng Y, Feng Y, Liao G, Sun Y, Ma J. Characteristics and mechanisms of controlled-release KMnO 4 for groundwater remediation: Experimental and modeling investigations. WATER RESEARCH 2020; 171:115385. [PMID: 31855695 DOI: 10.1016/j.watres.2019.115385] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/03/2019] [Accepted: 12/08/2019] [Indexed: 06/10/2023]
Abstract
Controlled release materials (CRMs) are emerging oxidant delivery techniques for in-situ chemical oxidation (ISCO) for groundwater remediation. Successful implementation of CRM relies on good understandings of the kinetics and mechanism of controlled release of reactive agents. In this study, batch experiments and model simulations were conducted to explore the impacts of CRM properties (composition and size) and environmental conditions (temperature, pH, water volume and anions) on KMnO4 release from KMnO4 -paraffin controlled release beads. Experimental results indicated that higher KMnO4: paraffin mass ratio resulted in shorter release longevities and higher release rate. Larger bead resulted in lower release rate, longer release longevity, and more KMnO4 released. Higher incubation temperature resulted in higher release rate and shorter release longevity, but did not affect the total mass of KMnO4 released. Acidic pH decreased the total mass of KMnO4 released while alkaline pH did not affect KMnO4 release. The presence of SO42-, CO32-, Cl- and Br- had negligible impacts on KMnO4 release. A dissolution-diffusion conceptual model was developed. The above experimental observation and the associated controlled release mechanisms can be qualitatively explained by the conceptual model. A more detailed two-film boundary mathematical model was developed to simulate KMnO4 release process. Comparison of modeling results with experimental data suggest that the new mathematical model gave a good quantitatively predication. Overall, this study shows that properly designed CRM can sustain release for years, thus representing a cost-effective and low-maintenance groundwater remediation technology. Both CRM properties and environmental conditions significantly affect the release kinetics and longevity, therefore these factors should be considered in the design and maintenance of CRM-based ISCO system.
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Affiliation(s)
- Yao Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yuan Feng
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yulin Feng
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Gaoming Liao
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Yue Sun
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China
| | - Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
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O'Connor D, Hou D, Ok YS, Song Y, Sarmah AK, Li X, Tack FM. Sustainable in situ remediation of recalcitrant organic pollutants in groundwater with controlled release materials: A review. J Control Release 2018; 283:200-213. [DOI: 10.1016/j.jconrel.2018.06.007] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/02/2018] [Accepted: 06/04/2018] [Indexed: 11/29/2022]
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Yang S, Oostrom M, Truex MJ, Li G, Zhong L. Injectable silica-permanganate gel as a slow-release MnO4(-) source for groundwater remediation: rheological properties and release dynamics. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:256-264. [PMID: 26766607 DOI: 10.1039/c5em00559k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Injectable slow-release permanganate gels (ISRPGs), formed by mixing aqueous KMnO4 solution with fumed silica powders, may have potential applications in remediating chlorinated solvent plumes in groundwater. A series of batch, column, and two-dimensional (2-D) flow cell experiments has been completed to characterize the ISRPG and study the release of permanganate (MnO4(-)) under a variety of conditions. The experiments have provided information on ISRPG rheology, MnO4(-) release dynamics and distribution in porous media, and trichloroethene (TCE) destruction by the ISRPG-released oxidant. The gel possesses shear thinning characteristics, resulting in a relatively low viscosity during mixing, and facilitating subsurface injection and distribution. Batch tests clearly showed that MnO4(-) diffused out from the ISRPG into water. During this process, the gel did not dissolve or disperse into water, but rather maintained its initial shape. Column experiments demonstrated that MnO4(-) release from the ISRPG lasted considerably longer than that from an aqueous solution. In addition, due to the longer release duration, TCE destruction by ISRPG-released MnO4(-) was considerably more effective than that when MnO4(-) was delivered using aqueous solution injection. In the 2-D flow cell experiments, it was demonstrated that ISRPGs released a long-lasting, low-concentration MnO4(-) plume potentially sufficient for sustainable remediation in aquifers.
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Affiliation(s)
- S Yang
- School of Environment, Tsinghua University, Beijing 100084, China and State Key Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - M Oostrom
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | - M J Truex
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | - G Li
- School of Environment, Tsinghua University, Beijing 100084, China and State Key Laboratory of Environmental Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - L Zhong
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
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