1
|
Sobral B, Samper J, Montenegro L, Mon A, Guadaño J, Gómez J, San Román J, Delgado F, Fernández J. 2D model of groundwater flow and total dissolved HCH transport through the Gállego alluvial aquifer downstream the Sardas landfill (Huesca, Spain). JOURNAL OF CONTAMINANT HYDROLOGY 2024; 265:104370. [PMID: 38851128 DOI: 10.1016/j.jconhyd.2024.104370] [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: 03/22/2024] [Revised: 05/15/2024] [Accepted: 05/30/2024] [Indexed: 06/10/2024]
Abstract
The organic pollutants disposed at the Sardas landfill in Sabiñánigo (Huesca, northeastern Spain) by the INQUINOSA lindane factory have reached the Gállego alluvial aquifer and could affect the Sabiñánigo reservoir. The daily oscillations of the reservoir water level produce a tidal effect on the piezometric heads of the aquifer. These oscillations are transmitted in a damped way with a time lag, thus attesting that the silting sediments of the reservoir and the natural silts of the Gállego alluvial are interposed between the reservoir water and the layer of sands and gravels. A 2D finite element groundwater flow and total dissolved hexachlorocyclohexane (HCH) transport model through the Gállego alluvial aquifer is presented here. The flow model was constructed to: (1) Quantify the tidal effect, produced by the daily fluctuations of the reservoir water level on the aquifer; (2) Estimate the hydrodynamic parameters of the layer of sands and gravels; and 3) Estimate the vertical hydraulic conductivity of the silting sediments and silts; and (4) Quantify aquifer/reservoir interactions. The flow model reproduces the dynamics of the tidal effect and attests that groundwater velocity and flow direction changes daily in response to the oscillations of the reservoir level. Model results reproduce the measured well hydrographs and the Darcy velocity derived from tracer tests and confirm the validity of the conceptual model. The transport model of total dissolved HCH simulates the time evolution of the contaminant plume. The computed concentrations of total dissolved HCH and the contaminant mass outflux are very sensitive to changes in the source terms and the distribution coefficient, Kd of HCH. The best fit to the measured HCH plumes in September 2010 and December 2020 is obtained with a Kd ranging from 1 to 3 L/kg. The computed flux of dissolved HCH leaving the Sardas site in 2020 towards the Sabiñánigo reservoir ranges from 0.6 kg/year for Kd = 3 L/kg to 3.1 kg/year for Kd = 1 L/kg. The findings of this study will be most useful for planning and designing remedial and containment actions at the Sardas site and other similar lindane-affected sites.
Collapse
Affiliation(s)
- Brais Sobral
- Civil Engineering Department & School, Interdisciplinar Center for Biology and Chemistry (CICA), Universidade da Coruña, Campus de Elviña, A Coruña 15071, Spain
| | - Javier Samper
- Civil Engineering Department & School, Interdisciplinar Center for Biology and Chemistry (CICA), Universidade da Coruña, Campus de Elviña, A Coruña 15071, Spain.
| | - Luis Montenegro
- Civil Engineering Department & School, Interdisciplinar Center for Biology and Chemistry (CICA), Universidade da Coruña, Campus de Elviña, A Coruña 15071, Spain
| | - Alba Mon
- Civil Engineering Department & School, Interdisciplinar Center for Biology and Chemistry (CICA), Universidade da Coruña, Campus de Elviña, A Coruña 15071, Spain
| | - Joaquín Guadaño
- Empresa Para la Gestión de Residuos Industriales, S.A., S.M.E., M.P., EMGRISA, C/ Santiago Rusiñol 12, 28040 Madrid, Spain
| | - Jorge Gómez
- Empresa Para la Gestión de Residuos Industriales, S.A., S.M.E., M.P., EMGRISA, C/ Santiago Rusiñol 12, 28040 Madrid, Spain
| | - Javier San Román
- Ebro Water District, Paseo Sagasta, 24-26, Zaragoza 50071, Spain
| | - Felipe Delgado
- Ebro Water District, Paseo Sagasta, 24-26, Zaragoza 50071, Spain
| | - Jesús Fernández
- Servicio de Prevención y Corrección de la Contaminación del Suelo, Dirección General de Calidad Ambiental, Departamento de Medio Ambiente y Turismo, Gobierno de Aragón. San pedro Nolasco, 7, 50071 Zaragoza, Spain
| |
Collapse
|
2
|
Herraiz-Carboné M, Santos A, Hayat A, Domínguez CM, Cotillas S. Remediation of groundwater polluted with lindane production wastes by conductive-diamond electrochemical oxidation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171848. [PMID: 38518821 DOI: 10.1016/j.scitotenv.2024.171848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/02/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
This work studies the remediation of groundwater saturated with dense non-aqueous phase liquid (DNAPL) from lindane production wastes by electrochemical oxidation. DNAPL-saturated groundwater contains up to 26 chlorinated organic compounds (COCs), including different isomers of hexachlorocyclohexane (HCH). To do this, polluted groundwater was electrolysed using boron-doped diamond (BDD) and stainless steel (SS) as anode and cathode, respectively, and the influence of the current density on COCs removal was evaluated in the range from 5 to 50 mA cm-2. Results show that current densities higher than 25 mA cm-2 lead to the complete removal and mineralisation of all COCs identified in groundwater. The higher the current density, the higher the COCs removal rate. At lower current densities (5 mA cm-2), chlorobenzenes were completely removed, and degradations above 90 % were reached for COCs with more than five chlorine atoms in their molecules. The use of BDD anodes promotes the electrochemical generation of powerful reactive species, such as persulfate, hypochlorite or hydroxyl radicals, that contribute to the degradation and mineralisation of COCs. The applied current density also influences the generation of these species. Finally, no acute toxicity towards Vibrio fischeri was observed for the treated groundwater after the electrochemical oxidation performed at 5 and 10 mA cm-2. These findings demonstrate that electrochemical oxidation with BDD anodes at moderate current densities is a promising alternative for the remediation of actual groundwater contaminated with DNAPLs.
Collapse
Affiliation(s)
- Miguel Herraiz-Carboné
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
| | - Aurora Santos
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
| | - Ana Hayat
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
| | - Carmen M Domínguez
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain
| | - Salvador Cotillas
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain.
| |
Collapse
|
3
|
Conte LO, Cotillas S, Lorenzo D, Bahamonde A, Santos A. Solar-assisted oxidation of organochlorine pesticides in groundwater using persulfate and ferrioxalate. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 343:123205. [PMID: 38142033 DOI: 10.1016/j.envpol.2023.123205] [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: 09/22/2023] [Revised: 12/07/2023] [Accepted: 12/20/2023] [Indexed: 12/25/2023]
Abstract
The oxidation of hexachlorocyclohexane isomers in the aqueous phase (Milli-Q and groundwater) was studied using persulfate activated by ferrioxalate and solar light at circumneutral pH. The experiments were conducted in a solar simulator reactor with local radiation fluxes qw= 1.12·10-7 E cm-2s-1 and in compound parabolic collectors with solar light (qw≈10-7 E cm-2s-1) for 390 min. The effect of activator dosage (18-125 μM ferrioxalate) and persulfate concentration (520-2600 μM) on hexachlorocyclohexane conversion and oxalate and oxidant consumption was analyzed. Conversion of about 95% of β isomer was achieved at 390 min using 1300 μM of initial persulfate and 63 μM of Fe3+ concentration despite this β isomer being the most recalcitrant to oxidation (XHexachlorocyclohexanes=0.98). Dechlorination above 80% was achieved under these conditions, analyzing the chlorides released into the water. The influence of chloride and bicarbonate on hexachlorocyclohexanes degradation was analyzed in milli-Q water and in groundwater. Hexachlorocyclohexane conversion at 390 min decreases from 98% to 83, 75 and 65% in the presence of chloride, bicarbonate or groundwater, respectively. Results obtained with compound parabolic collectors and solar light using 2600 μM Na2S2O8 and 63 μM Fe for removing hexachlorocyclohexanes agreed with those from the solar simulator reactor, supporting using solar light to activate persulfate for sustainable abatement of persistent organic pollutants in aqueous matrixes.
Collapse
Affiliation(s)
- Leandro O Conte
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040, Madrid, Spain; Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Universidad Nacional del Litoral (UNL), Ruta Nacional N 168, 3000, Santa Fe, Argentina
| | - Salvador Cotillas
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040, Madrid, Spain
| | - David Lorenzo
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040, Madrid, Spain
| | - Ana Bahamonde
- Instituto de Catálisis y Petroleoquímica, ICP-CSIC, C/ Marie Curie 2, 28049, Madrid, Spain
| | - Aurora Santos
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040, Madrid, Spain.
| |
Collapse
|
4
|
Liu Y, Wang F, Wang Z, Xiang L, Fu Y, Zhao Z, Kengara FO, Mei Z, He C, Bian Y, Naidu R, Jiang X. Soil properties and organochlorine compounds co-shape the microbial community structure: A case study of an obsolete site. ENVIRONMENTAL RESEARCH 2024; 240:117589. [PMID: 37926227 DOI: 10.1016/j.envres.2023.117589] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/28/2023] [Accepted: 11/02/2023] [Indexed: 11/07/2023]
Abstract
Organochlorine compounds (OCs) such as chlorobenzenes (CB) are persistent organic pollutants that are ubiquitous in soils at organochlorine pesticides (OCP) production sites. Long-term contamination with OCs might alter the soil microbial structure and further affect soil functions. However, the effects of OCs regarding the shaping of microbial community structures in the soils of OCs-contaminated sites remain obscure, especially in the vertical soil profile where pollutants are highly concealed. Hence this paper explored the status and causes of OCs pollution (CB, hexachlorocyclohexane (HCH), and dichlorodiphenyltrichloroethane (DDT)) in an obsolete site, and its combined effects with soil properties (pH, available phosphorus (AP), dissolved organic carbon (DOC), etc) on microbial community structure. The mean total concentration of OCs in the subsoils was up to 996 times higher than that in the topsoils, with CB constituting over 90% of OCs in the subsoil. Historical causes, anthropogenic effects, soil texture, and the nature of OCs contributed to the differences in the spatial distribution of OCs. Redundancy analysis revealed that both the soil properties and OCs were important factors in shaping microbial composition and diversity. Variation partitioning analysis further indicated that soil properties had a greater impact on microbial community structure than OCs. Significant differences in microbial composition between topsoils and subsoils were observed through linear discriminant analysis effect size (LEfSe) analysis, primarily driven by different pollutant conditions. Additionally, co-occurrence network analysis indicated that heavily contaminated subsoils exhibited closer and more intricate bacterial community interactions compared to lightly contaminated topsoils. This work reveals the impact of environmental factors in co-shaping the structure of soil microbial communities. These findings advance our understanding of the intricate interplay among organochlorine pollutants, soil properties, and microbial communities, and provides valuable insights into devising effective management strategies in OCs-contaminated soils.
Collapse
Affiliation(s)
- Yu Liu
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Wang
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ziquan Wang
- College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Leilei Xiang
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuhao Fu
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiliang Zhao
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Zhi Mei
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao He
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Yongrong Bian
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), University of Newcastle, Callaghan, NSW 2308, Australia; Crc for Contamination Assessment and Remediation of the Environment (crcCARE), University of Newcastle, Callaghan, NSW 2308, Australia
| | - Xin Jiang
- Chinese Academy of Science State Key Laboratory of Soil & Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
5
|
Sáez P, García-Cervilla R, Santos A, Romero A, Lorenzo D. Treatment of a Complex Emulsion of a Surfactant with Chlorinated Organic Compounds from Lindane Wastes under Alkaline Conditions by Air Stripping. Ind Eng Chem Res 2023; 62:3282-3293. [PMID: 36853619 PMCID: PMC9951212 DOI: 10.1021/acs.iecr.2c03722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/10/2023]
Abstract
Surfactant-enhanced aquifer remediation is commonly applied in polluted sites with dense non-aqueous phase liquids (DNAPLs). This technique transfers the contamination from subsoil to an extracted emulsion, which requires further treatment. This work investigated the treatment of a complex emulsion composed of a nonionic surfactant and real DNAPL formed of chlorinated organic compounds (COCs) and generated as a lindane production waste by air stripping under alkaline conditions. The influence of the surfactant (1.5-15 g·L-1), COC concentrations (2.3-46.9 mmol·L-1), and temperature (30-60 °C) on the COC volatilization was studied and modeled in terms of an apparent constant of Henry at pH > 12. In addition, the surfactant stability was studied as a function of temperature (20-60 °C) and surfactant (2-10 g·L-1), COC (0-70.3 mmol·L-1), and NaOH (0-4 g·L-1) concentrations. A kinetic model was successfully proposed to explain the loss of surfactant capacity (SCL). The results showed that alkali and temperature caused the SCL by hydrolysis of the surfactant molecule. The increasing surfactant concentration decreased the COC volatility, whereas the temperature improved the COC volatilization. Finally, the volatilization of COCs in alkaline emulsions by air stripping (3 L·h-1) was performed to evaluate the treatment of an emulsion composed of the COCs (17.6 mmol·kg-1) and surfactant (3.5 and 7 g·L-1). The air stripping was successfully applied to remove COCs (>90%), reaching an SCL of 80% at 60 °C after 8 h. Volatilization can remove COCs from emulsions and break them, enhancing their further disposal.
Collapse
|
6
|
Domínguez CM, Ventura P, Checa-Fernández A, Santos A. Comprehensive study of acute toxicity using Microtox® bioassay in soils contaminated by lindane wastes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159146. [PMID: 36191709 DOI: 10.1016/j.scitotenv.2022.159146] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
This research studies the acute toxicity of real contaminated soils (topsoil and subsoil) with hazardous chlorinated organic compounds (COCs) from lindane manufacturing wastes. The Microtox® bioassay was used to determine the toxicity of soils (modified Basic Solid Phase Test), soil elutriates (Basic Test), and organic extracts (adapted Organic Solvent Sample Solubilization Test), in which hydrophobic organic compounds are soluble. The acute toxicity of these persistent contaminants (hexachlorocyclohexanes, HCH isomers, as particulate matter in topsoil, and COCs, from dense non-aqueous phase liquid, DNAPL, in subsoil) and the commercial compounds were also measured. Soils tested showed different contaminant levels (topsoil: 0.9-1149 mg/kg and subsoil: 20-9528 mg/kg). Soil contaminants distribution, concentration and acute toxicity were highly related to the contamination source (HCHs or DNAPL). Soils, organic extracts, and subsoil elutriates presented high toxicity, highlighting the need for remediation of these sites. EC50 was calculated in the three-test applied for the soils tested. EC50 vs. COCs concentration in soils and soil elutriates showed an asymptotic trend, explained by the low pollutants solubility in the aqueous phase. Contrarily, EC50 vs. soil COCs concentration was more linear in the case of the organic extracts. This test was the most reliable from statistical analysis. The three methods reveal interesting and complementary information and are necessary for a complete overview of the acute toxicity of contaminated soils.
Collapse
Affiliation(s)
- Carmen M Domínguez
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain.
| | - Paula Ventura
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| | - Alicia Checa-Fernández
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| | - Aurora Santos
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| |
Collapse
|
7
|
Santos A, García-Cervilla R, Checa-Fernández A, Domínguez CM, Lorenzo D. Acute Toxicity Evaluation of Lindane-Waste Contaminated Soils Treated by Surfactant-Enhanced ISCO. Molecules 2022; 27:molecules27248965. [PMID: 36558105 PMCID: PMC9786798 DOI: 10.3390/molecules27248965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
The discharge of lindane wastes in unlined landfills causes groundwater and soil pollution worldwide. The liquid waste generated (a mixture of 28 chlorinated organic compounds, COCs) constitutes a dense non-aqueous phase liquid (DNAPL) that is highly persistent. Although in situ chemical oxidation (ISCO) is effective for degrading organic pollutants, the low COCs solubility requires high reaction times. Simultaneous injection of surfactants and oxidants (S-ISCO) is a promising technology to solve the limitation of ISCO treatment. The current work studies the remediation of highly polluted soil (COCs = 3682 mg/kg) obtained at the Sardas landfill (Sabiñáñigo, Spain) by ISCO and S-ISCO treatments. Special attention is paid to acute soil toxicity before and after the soil treatment. Microtox®, modified Basic Solid-Phase Test (mBSPT) and adapted Organic Solvent Sample Solubilization Test (aOSSST) were used for this scope. Persulfate (PS, 210 mM) activated by alkali (NaOH, 210 mM) was used in both ISCO and S-ISCO runs. A non-ionic and biodegradable surfactant selected in previous work, Emulse®3 (E3, 5, and 10 g/L), was applied in S-ISCO experiments. Runs were performed in soil columns filled with 50 g of polluted soil, with eight pore volumes (Pvs) of the reagents injected and 96 h between successive Pv injections. The total treatment time was 32 days. The results were compared with those corresponding without surfactant (ISCO). After remediation treatments, soils were water-washed, simulating the conditions of groundwater flux in the subsoil. The treatments applied highly reduced soil toxicity (final soil toxicity equivalent to that obtained for non-contaminated soil, mBSPT) and organic extract toxicity (reduction > 95%, aOSSST). Surfactant application did not cause an increase in the toxicity of the treated soil, highlighting its suitability for full-scale applications.
Collapse
|
8
|
Li Y, Liu Y, Zhang X, Tian K, Tan D, Song X, Wang P, Jiang Q, Lu J. Electrochemical Reduction and Oxidation of Chlorinated Aromatic Compounds Enhanced by the Fe-ZSM-5 Catalyst: Kinetics and Mechanisms. ACS OMEGA 2022; 7:33500-33510. [PMID: 36157725 PMCID: PMC9494633 DOI: 10.1021/acsomega.2c04458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/31/2022] [Indexed: 06/16/2023]
Abstract
Devising cost-effective electrochemical catalyst system for the efficient degradation of chlorinated aromatic compounds is urgently needed for environmental pollution control. Herein, a Fe-ZSM-5 zeolite was used as a suspended catalyst to facilitate the degradation of lindane as a model chlorinated pesticide in an electrochemical system consisting of the commercial DSA (Ti/RuO2-IrO2) anode and graphite cathode. It was found that the Fe-ZSM-5 zeolite greatly accelerated the degradation of lindane, with the degradation rate constant more than 8 times higher than that without Fe-ZSM-5. In addition, the Fe-ZSM-5 zeolite widened the working pH range from 3 to 11, while efficient degradation of lindane in the absence of Fe-ZSM-5 was only obtained at pH ≤ 5. The degradation of lindane was primarily due to reductive dechlorination mediated by atomic H* followed by •OH oxidation. Fe-ZSM-5 zeolite could enrich lindane, H*, and •OH on its surface, thus provided a suitable local environment for lindane degradation. The Fe-ZSM-5 zeolite exhibited high stability and reusability, and reduced the energy consumption. This research provides a potential reduction-oxidation strategy for removing organochlorine compounds through a cost-efficient Fe-ZSM-5 catalytic electrochemical system.
Collapse
Affiliation(s)
- Yuexuan Li
- Key
Laboratory of Soil Environment and Pollution Remediation, Institute
of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- Lanzhou
Jiaotong University, Lanzhou 730070, China
| | - Yun Liu
- Key
Laboratory of Soil Environment and Pollution Remediation, Institute
of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University
of Chinese Academy of Sciences, Beijing 100000, China
| | - Xuan Zhang
- Lanzhou
Jiaotong University, Lanzhou 730070, China
| | - Kun Tian
- Key
Laboratory of Soil Environment and Pollution Remediation, Institute
of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University
of Chinese Academy of Sciences, Beijing 100000, China
| | - Ding Tan
- Key
Laboratory of Soil Environment and Pollution Remediation, Institute
of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
- University
of Chinese Academy of Sciences, Beijing 100000, China
| | - Xiaosan Song
- Lanzhou
Jiaotong University, Lanzhou 730070, China
| | - Ping Wang
- Lanzhou
Jiaotong University, Lanzhou 730070, China
| | - Qian Jiang
- Key
Laboratory of Soil Environment and Pollution Remediation, Institute
of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Junhe Lu
- College
of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| |
Collapse
|
9
|
Zhang Z, Liu X, Huang J, Xu H, Ren W, Lin C, He M, Ouyang W. Horizontal planetary mechanochemical method for rapid and efficient remediation of high-concentration lindane-contaminated soils in an alkaline environment. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129078. [PMID: 35533523 DOI: 10.1016/j.jhazmat.2022.129078] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/28/2022] [Accepted: 05/02/2022] [Indexed: 06/14/2023]
Abstract
Lindane is a persistent organic pollutant that has attracted worldwide attention because of its threat to human health and environmental security. A horizontal planetary mechanochemical method was developed for rapid and efficient degradation of lindane in soil in an alkaline environment. Under the condition of a very low reagent-to-soil ratio (R = 2%), ball-to-powder ratio (CR = 6:1), rotation speed (r = 300 rpm) and high soil single treatment capacity (SC = 60 g), the lindane in four typical soils (~ 100 mg/kg) can be degraded up to 96.30% in 10 min. This method can also remediate high-concentration lindane-contaminated soil (833 ± 26 mg/kg). The experimental results and theoretical calculations proved that the stepwise dechlorination and final carbonization of lindane in soil are mainly attributed to the combined action of mechanical energy and alkalinity. The bimolecular elimination (E2) reaction was the first step of lindane destruction. Subsequently, the unimolecular elimination (E1) reaction tended to occur with the weakening of alkalinity. Then, benzene was obtained through stepwise hydrogenolysis reaction. The last was the generation of carbon substances by fragmentation or condensation of benzene rings. This work proposes a practical remediation technology for organic contaminated soil and improves the understanding of the degradation pathways of lindane in soil in alkali-assisted mechanochemical system.
Collapse
Affiliation(s)
- Zhenguo Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xitao Liu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Jun Huang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control (BKLEOC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Hengpu Xu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Wenbo Ren
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Chunye Lin
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Mengchang He
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Wei Ouyang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China; Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China
| |
Collapse
|
10
|
Srivastava V, Puri M, Srivastava T, Nidheesh PV, Kumar MS. Integrated soil washing and bioreactor systems for the treatment of hexachlorocyclohexane contaminated soil: A review on enhanced degradation mechanisms, and factors affecting soil washing and bioreactor performances. ENVIRONMENTAL RESEARCH 2022; 208:112752. [PMID: 35065935 DOI: 10.1016/j.envres.2022.112752] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Investigations about the remediation of Hexachlorocyclohexane (HCH), a persistent organic pollutant of global concern, have been extensively reported to treat the HCH contaminated soil. The difficulty arising due to desorption and long ageing procedures of this hydrophobic organic compound in the soil, make it necessary to exploit techniques like soil washing or addition of surfactants, for enhancing the mass transfer rate of hydrophobic compounds. However, this technique gives rise to the generation of a large quantity of waste solution containing the pollutant and various other toxic substances. Moreover, it is challenging to deal with the complex soil washing solution, and thus a follow-up treatment of such washing solution is essentially required before its discharge. This follow-up treatment could be the bioreactor system to efficiently treat the pollutant in the wash solution, thereby reducing the amount of contaminated soil that has to be treated. Among many suggested remediation methods and treatment technologies, integrated soil washing and post-treatment with the bioreactor system could be an environmentally viable method for the remediation of HCH contaminated sites. This review focuses on the soil washing procedures applied so far for the HCH contaminated soil and various factors affecting the efficiency of separation of the target pollutant. Furthermore, the environmental and reactor design-related factors are also discussed for degradation of HCH in the reactor system. Finally, advantages and environmental feasibility of this proposed combined technology and the challenges that need to be encountered are envisaged.
Collapse
Affiliation(s)
- Vartika Srivastava
- CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Mehak Puri
- CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Tanmay Srivastava
- CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - P V Nidheesh
- CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| | - M Suresh Kumar
- CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur, 440020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| |
Collapse
|
11
|
Garcia-Cervilla R, Santos A, Romero A, Lorenzo D. Abatement of chlorobenzenes in aqueous phase by persulfate activated by alkali enhanced by surfactant addition. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 306:114475. [PMID: 35033888 DOI: 10.1016/j.jenvman.2022.114475] [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: 09/13/2021] [Revised: 12/22/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
Sites polluted by dense non-aqueous phases (DNAPLs) constitute an environmental concern. In situ chemical oxidation (ISCO) application is limited since oxidation often occurs in the aqueous phase and contaminants are usually hydrophobic. In this work, ISCO enhanced by the surfactant addition (S-ISCO) was studied for a complex liquid mixture of chlorinated organic compounds (COCs) using persulfate (PS) activated by alkali (PSA) as oxidant and Emulse-3® as a commercial non-ionic surfactant. The reaction between E3 and PSA was investigated in the absence and presence of solubilized COCs in the following concentration ranges: COCs 1.2-50 mM, PS 84-336 mM, NaOH:PS molar ratio of 2, and surfactant concentration 1-10 g·L-1. In the experiments carried out in the absence of COCs, the unproductive consumption of PS was studied. The higher the surfactant concentration, the lower the ratio PS consumed to the initial surfactant concentration due to more complex micelle structures hindering the oxidation of surfactant molecules. This hindering effect was also noticed in the oxidation of solubilized COCs. The reduction of chlorobenzenes by PSA was negligible at surfactant concentrations above 2.5 g·L-1, independently of the COCs concentration solubilized. Instead, a surfactant concentration of about 1 and PS concentration of 168 mM yielded a significant decrease in the time required to abate a mass of DNAPL, compared with an ISCO process, with a bearable increase in the unproductive consumption of PS.
Collapse
Affiliation(s)
- Raul Garcia-Cervilla
- Chemical and Materials Engineering Department, Complutense University of Madrid, Spain
| | - Aurora Santos
- Chemical and Materials Engineering Department, Complutense University of Madrid, Spain
| | - Arturo Romero
- Chemical and Materials Engineering Department, Complutense University of Madrid, Spain
| | - David Lorenzo
- Chemical and Materials Engineering Department, Complutense University of Madrid, Spain.
| |
Collapse
|
12
|
Checa-Fernández A, Santos A, Romero A, Domínguez CM. Remediation of real soil polluted with hexachlorocyclohexanes (α-HCH and β-HCH) using combined thermal and alkaline activation of persulfate: Optimization of the operating conditions. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
13
|
Dominguez CM, Romero A, Checa-Fernandez A, Santos A. Remediation of HCHs-contaminated sediments by chemical oxidation treatments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:141754. [PMID: 32889469 DOI: 10.1016/j.scitotenv.2020.141754] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/23/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
The intensive use of organochlorine pesticides, such as lindane (γ-HCH), and the inadequate management of their wastes, is a huge environmental problem. The lindane production during the last century has generated huge volumes of solid wastes of other HCH isomers, causing hot points of soil and groundwater contamination. The soil treated in this work was obtained from a landfill located in the nearby of an old lindane factory, containing α-HCH and β-HCH as main contaminants. This study addresses for the first time the application of different chemical oxidation treatments, viz. Fenton process (H2O2 + Fe), persulfate (PS) activated by temperature (20 and 40 °C), by alkali (NaOH) and by the combination of alkali and temperature (NaOH, 40 °C) for the remediation of HCH-polluted soils (CHCHs = 155 mg kg-1). The intrinsic characteristics of the soil (high carbonate content) led to high consumption of H2O2 (XH2O2 ≈ 100% at 24 h) and complete iron precipitation, making unappropriated the application of the Fenton process. The efficiency of thermal PS was limited by the low solubility of HCH isomers in the aqueous phase, the high refractoriness of these compounds towards oxidation, and the presence of the contaminants in the form of particulate matter. After 25 days of treatment, a conversion of chlorinated organic compounds (COCs) of 50% was achieved (VL/Wsoil = 2, CPS = 40 g L-1, 40 °C), whereas the application of PS activated by alkali and temperature (40 °C) led to promising results. At pH above 12, HCHs were dehydrochlorinated to trichlorobenzenes, which were further oxidized by hydroxyl radicals. The hydrolysis rate of β-HCH was the limiting step of the process, and it was favored by increasing the reaction temperature. At 40 °C, a conversion of COCs above 95% was achieved (VL/Wsoil = 2, CPS = 40 g L-1, CNaOH = 13.5 g L-1, 14 days) with low oxidant consumption (XPS = 30%).
Collapse
Affiliation(s)
- Carmen M Dominguez
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| | - Arturo Romero
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| | - Alicia Checa-Fernandez
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain
| | - Aurora Santos
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain.
| |
Collapse
|
14
|
García-Cervilla R, Santos A, Romero A, Lorenzo D. Compatibility of nonionic and anionic surfactants with persulfate activated by alkali in the abatement of chlorinated organic compounds in aqueous phase. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:141782. [PMID: 32882562 DOI: 10.1016/j.scitotenv.2020.141782] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/16/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Surfactant Enhanced In-Situ Chemical Oxidation (S-ISCO) is an emerging technology in the remediation of sites with residual Dense Non-Aqueous Phase Liquids (DNAPLs), a ubiquitous problem in the environment and a challenge to solve. In this work, three nonionic surfactants: E-Mulse3® (E3), Tween80 (T80), and a mixture of Tween80-Span80 (TS80), and an anionic surfactant: sodium dodecyl sulfate (SDS), combined with persulfate activated by alkali (PSA) as oxidant have been investigated to remove the DNAPL generated as liquid waste in lindane production, which is composed of 28 chlorinated organic compounds (COCs). Because the compatibility between surfactants and oxidants is a key aspect in the S-ISCO effectiveness the unproductive consumption of PS by surfactants was investigated in batch (up to 864 h) varying the initial concentration of PS (84-42 mmol·L-1) and surfactants (0-12 g·L-1) and the NaOH:PS molar ratio (1 and 2). The solubilization capacity of a partially oxidized surfactant was analyzed by estimating its Equivalent Surfactant Capacity, ESC, (as mmolCOCs dissolvedgsurf-1) and comparing it to the expected value for an unoxidized surfactant, ESCo. Finally, the abatement of DNAPL with simultaneous addition of surfactant and PSA was studied. At the conditions used, a negligible unproductive consumption of PS was found by SDS; meanwhile, PS consumption at 360 h ranged between 70 and 80% using the nonionic surfactants. The highest ratios of ESC/ESCo were found with SDS and E3 and these surfactants were chosen for the S-ISCO treatment. When oxidant and surfactant were simultaneously applied for DNAPL abatement the COC conversion was more than three times higher with E3 (0.6 at 360 h) than SDS. Moreover, it was obtained that the time needed for the removal of a mass of DNAPL by PSA in the absence of surfactants was notably higher than the time required when a suitable surfactant was added.
Collapse
Affiliation(s)
- Raul García-Cervilla
- Chemical Engineering and Materials Department, University Complutense of Madrid, Spain.
| | - Aurora Santos
- Chemical Engineering and Materials Department, University Complutense of Madrid, Spain.
| | - Arturo Romero
- Chemical Engineering and Materials Department, University Complutense of Madrid, Spain.
| | - David Lorenzo
- Chemical Engineering and Materials Department, University Complutense of Madrid, Spain.
| |
Collapse
|
15
|
Bouzid I, Maire J, Laurent F, Broquaire M, Fatin-Rouge N. Controlled treatment of a high velocity anisotropic aquifer model contaminated by hexachlorocyclohexanes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115678. [PMID: 33007599 DOI: 10.1016/j.envpol.2020.115678] [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: 05/12/2020] [Revised: 09/02/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
Xanthan gels were assessed to control the reductive dechlorination of hexachlorocyclohexanes (HCHs) and trichlorobenzenes (TCBs) in a strong permeability contrast and high velocity sedimentary aquifer. An alkaline degradation was selected because of the low cost of NaOH and Ca(OH)2. The rheology of alkaline xanthan gels and their ability to deliver alkalinity homogeneously, while maintaining the latter, were studied. Whereas the xanthan gels behaved like non-Newtonian shear-thinning fluids, alkalinity and Ca(OH)2 microparticles had detrimental effects, yet, the latter decreased with the shear-rate. Breakthrough curves for the NaOH and Ca(OH)2 in xanthan solutions, carried out in the lowest permeability soil (9.9 μm2), demonstrated the excellent transmission of alkalinity, while moderate pressure gradients were applied. Injection velocities ranging from 1.8 to 3.8 m h-1 are anticipated in the field, given the permeability range from 9.9 to 848.7 μm2. Despite a permeability contrast of 8.7 in an anisotropic aquifer model, the NaOH and the Ca(OH)2 both in xanthan gels spread only 5- and 7-times faster in the higher permeability zone, demonstrating that the delivery was enhanced. Moreover, the alkaline gels which were injected into a high permeability layer under lateral water flow, showed a persistent blocking effect and longevity (timescale of weeks), in contrast to the alkaline solution in absence of xanthan. Kinetics of alkaline dechlorination carried out on the historically contaminated soil, using the Ca(OH)2 suspension in xanthan solution, showed that HCHs were converted in TCBs by dehydrodechlorination, whereas the latter were then degraded by reductive hydrogenolysis. Degradation kinetics were achieved within 30 h for the major and most reactive fraction of HCHs.
Collapse
Affiliation(s)
- Iheb Bouzid
- Université de Bourgogne Franche-Comté-Besançon, Institut UTINAM-UMR CNRS 6213, 16, Route de Gray, 25030, Besançon, France
| | - Julien Maire
- Université de Bourgogne Franche-Comté-Besançon, Institut UTINAM-UMR CNRS 6213, 16, Route de Gray, 25030, Besançon, France
| | - Fabien Laurent
- SOLVAY, Centre de Recherche et Innovation de Lyon, DRP-ERA, 85 Rue des Frères Perret, 69192, Saint Fons, France
| | - Mathias Broquaire
- SOLVAY, Direction Réhabilitation Environnement, Parc Everest, 54 Rue Marcel Dassault, 69740, Genas, France
| | - Nicolas Fatin-Rouge
- Université de Bourgogne Franche-Comté-Besançon, Institut UTINAM-UMR CNRS 6213, 16, Route de Gray, 25030, Besançon, France.
| |
Collapse
|
16
|
Surfactant-Enhanced Solubilization of Chlorinated Organic Compounds Contained in DNAPL from Lindane Waste: Effect of Surfactant Type and pH. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17124494. [PMID: 32585799 PMCID: PMC7345101 DOI: 10.3390/ijerph17124494] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 11/30/2022]
Abstract
Application of surfactants in the remediation of polluted sites with dense nonaqueous phase liquid (DNAPL) still requires knowledge of partitioning between surfactants and pollutants in the organic and aqueous phases and the time necessary to reach this balance. Two real DNAPLs, generated as wastes in the lindane production and taken from the polluted sites from Sabiñanigo (Spain), were used for investigating the solubilization of 28 chlorinated organic compounds (COCs) applying aqueous surfactant solutions of three nonionic surfactants (E-Mulse® 3 (E3), Tween®80 (T80), and a mixture of Tween®80-Span®80 (TS80)) and an anionic surfactant (sodium dodecyl sulfate (SDS)). The initial concentrations of surfactants were tested within the range of 3–17 g·L−1. The pH was also modified from 7 to >12. The uptake of nonionic surfactants into the organic phase was higher than the anionic surfactants. Solubilization of COCs with the nonionic surfactants showed similar molar solubilization ratios (MSR = 4.33 mmolCOCs·g−1surf), higher than SDS (MSR = 0.70 mmolCOCs·g−1SDS). Furthermore, under strong alkaline conditions, the MSR value of the nonionic surfactants was unchanged, and the MSR of SDS value increased (MSR = 1.32 mmolCOCs·g−1SDS). The nonionic surfactants did not produce preferential solubilization of COCs; meanwhile, SDS preferentially dissolved the more polar compounds in DNAPL. The time required to reach phase equilibrium was between 24 and 48 h, and this contact time should be assured to optimize the effect of the surfactant injected on COC solubilization.
Collapse
|
17
|
Liu Y, Liu J, Renpenning J, Nijenhuis I, Richnow HH. Dual C-Cl Isotope Analysis for Characterizing the Reductive Dechlorination of α- and γ-Hexachlorocyclohexane by Two Dehalococcoides mccartyi Strains and an Enrichment Culture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7250-7260. [PMID: 32441516 DOI: 10.1021/acs.est.9b06407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hexachlorocyclohexanes (HCHs) are persistent organic contaminants that threaten human health. Microbial reductive dehalogenation is one of the most important attenuation processes in contaminated environments. This study investigated carbon and chlorine isotope fractionation of α- and γ-HCH during the reductive dehalogenation by three anaerobic cultures. The presence of tetrachlorocyclohexene (TeCCH) indicated that reductive dichloroelimination was the first step of bond cleavage. Isotope enrichment factors (εC and εCl) were derived from the transformation of γ-HCH (εC, from -4.0 ± 0.5 to -4.4 ± 0.6 ‰; εCl, from -2.9 ± 0.4 to -3.3 ± 0.4 ‰) and α-HCH (εC, from -2.4 ± 0.2 to -3.0 ± 0.4 ‰; εCl, from -1.4 ± 0.3 to -1.8 ± 0.2 ‰). During α-HCH transformation, no enantioselectivity was observed, and similar εc values were obtained for both enantiomers. The correlation of 13C and 37Cl fractionation (Λ = Δδ13C/Δδ37Cl ≈ εC/εCl) of γ-HCH (from 1.1 ± 0.3 to 1.2 ± 0.1) indicates similar bond cleavage during the reductive dichloroelimination by the three cultures, similar to α-HCH (1.7 ± 0.2 to 2.0 ± 0.3). The different isotope fractionation patterns during reductive dichloroelimination and dehydrochlorination indicates that dual-element stable isotope analysis can potentially be used to evaluate HCH transformation pathways at contaminated field sites.
Collapse
Affiliation(s)
- Yaqing Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Jia Liu
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Haidian District, Beijing 100083, PR China
| | - Julian Renpenning
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| | - Hans-Hermann Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, Leipzig 04318, Germany
| |
Collapse
|
18
|
Dominguez CM, Romero A, Lorenzo D, Santos A. Thermally activated persulfate for the chemical oxidation of chlorinated organic compounds in groundwater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 261:110240. [PMID: 32148309 DOI: 10.1016/j.jenvman.2020.110240] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/04/2020] [Accepted: 02/03/2020] [Indexed: 06/10/2023]
Abstract
Chlorinated pesticides were extensively produced in the XX century, generating high amounts of toxic wastes often dumped in the surroundings of the production sites, resulting in hot points of soil and groundwater pollution worldwide. This is the case of Bailín landfill, located in Sabiñánigo (Spain), where groundwater is highly polluted with chlorobenzenes (mono, di, tri and tetra) and hexachlorocyclohexanes. This study addresses the abatement of chlorinated organic compounds (COCs) present in the groundwater coming from the Bailín landfill by thermally activated persulfate, PS (TAP). The influence of temperature (30-50 °C) and oxidant concentration (2-40 g L-1) on the efficiency of COCs (initial concentration of COCs = 57.53 mg L-1, determined by the solubility of the pollutants in water) degradation has been investigated. Raising the reaction temperature and PS concentration the degradation of COCs significantly accelerates, as a result of higher production of sulfate radicals. The thermal activation of PS implies side reactions, involving the unproductive decomposition of this oxidant. The activation energy calculated for this reaction (128.48 kJ mol-1) reveals that is slightly more favored by temperature than the oxidation of COCs by sulfate radicals (102.4-115.72 kJ mol-1). At the selected operating conditions (PS = 10 g L-1, 40 °C), the almost complete conversion of COCs and a dechlorination and mineralization degree above 80% were obtained at 168 h reaction time. A kinetic model, able to adequately predict the experimental concentration of COCs when operating at different temperatures and initial concentration of PS has been proposed.
Collapse
Affiliation(s)
- Carmen M Dominguez
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040, Madrid, Spain
| | - Arturo Romero
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040, Madrid, Spain
| | - David Lorenzo
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040, Madrid, Spain
| | - Aurora Santos
- Dpto. Ingeniería Química y de Materiales, Facultad de Ciencias Químicas, Universidad Complutense Madrid, Ciudad Universitaria S/N, 28040, Madrid, Spain.
| |
Collapse
|