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Agrawal S, Nawaz T. A mechanistic mathematical model for the treatment of synthetic oil-field wastewater (produced water) by electrocoagulation process using aluminium electrodes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:20117-20132. [PMID: 38374501 DOI: 10.1007/s11356-024-32310-4] [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: 07/18/2023] [Accepted: 01/29/2024] [Indexed: 02/21/2024]
Abstract
Produced water (PW) is the largest by-product that comes out of the oil wells during oil and gas (O&G) field exploration. PW contains high-salt concentration along with other organic and inorganic components; therefore, PW must be treated before disposal. Electrocoagulation (EC) is an effective treatment method to remove pollutants from PW which has been the focus of many experimental studies; however, a mathematical model specifically for PW treatment by EC has not been developed yet. In this work, a comprehensive mathematical model has been developed to elucidate the role of EC operating parameters on the PW treatment performance and determine the mechanism for COD (Chemical Oxygen Demand) removal. The present model considers and identifies the dominant Al-hydroxy complex species and their contribution to the COD removal from synthetic PW samples by estimating their rate constants and comparing their magnitudes and investigates multi-scale modelling of the EC reactor. The influence of working parameters such as current density, initial pH, interelectrode distance, mixing speed and solution volume of PW on Al coagulant production and COD removal was investigated and modelled. The study estimates the rate constants of the reactions taking place for COD removal by EC process and by comparing their magnitudes identifies the dominant reactions and coagulant species involved in the process. The mathematical model prediction of COD removal fits well with the experimental data at 10 mA cm-2, 15 mA cm-2 and 20 mA cm-2 current density with R2 value of 0.96, 0.97 and 0.92, respectively and for dissolved Al concentration R2 value of 0.96, 0.99, and 0.97, respectively. The simulated results reproduced a good fit at initial pH of 6.1, 7.3 and 8.6 with R2 value of 0.92, 0.96 and 0.98, respectively for COD removal. The mathematical model and the experimental results showed the role of dominant Al-hydroxy complex species such asAl OH 2 + ,Al OH 2 + , Al OH 3 ,Al 2 OH 2 + 4 andAl OH 4 - in controlling the COD removal process. Under different operating conditions considered in the study, the model also predicted the COD removal performance of the EC reactors at different reactor volumes with R2 value of 0.96 for higher solution volume and larger reactor. The model presented and rate constants determined in the study will provide a theoretical basis for designing, scaling up and operating the EC reactor for oil-field PW treatment.
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Affiliation(s)
- Saumya Agrawal
- Environmental Science and Engineering Department (ESED), Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Tabish Nawaz
- Environmental Science and Engineering Department (ESED), Indian Institute of Technology Bombay, Mumbai, 400076, India.
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2
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Biswas B, Goel S. Electrocoagulation and electrooxidation technologies for pesticide removal from water or wastewater: A review. CHEMOSPHERE 2022; 302:134709. [PMID: 35489460 DOI: 10.1016/j.chemosphere.2022.134709] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/17/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
Pesticides are known to be threats to the environment and human health. Excessive use of pesticides in agricultural practice can contaminate water bodies, leading to cancer, asthma, neurological disorders, reproductive defects, and hormonal disruption. Electrochemical methods such as electrocoagulation and electrooxidation can be used for pesticide removal due to their numerous advantages such as high efficiency, less sludge production, and low operational cost. During electrocoagulation, dissolution of anode metals results in metal hydroxide complexes, which precipitate with the contaminant present in the reactor. Simultaneously, electro-flotation occurs at the cathode and results in the evolution of hydrogen gas bubbles, leading to flotation of floc to the top surface of the reactor. This review focuses on the removal mechanisms, kinetics, modeling, effects of influencing factors, and sludge characterization of pesticide removal using electrocoagulation and electrooxidation. Major influencing factors include cell configuration, electrode material, current density, pH, supporting electrolyte concentration. In general, aluminum and iron are the most common electrodes used for pesticide removal using electrocoagulation, while boron-doped diamond was used to a far greater extent as the electrode in electrooxidation studies. Greater than 99% removal efficiency was observed in both processes. Overall, this review summarizes the use of electrochemical methods for pesticide removal and offers valuable information to researchers in this area of study.
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Affiliation(s)
- Bishwatma Biswas
- Environmental Engineering and Management, Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India
| | - Sudha Goel
- Environmental Engineering and Management, Department of Civil Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, West Bengal, India.
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Andreatta D, Shonza NS, Muniz EP, Bacelos MS, Dalmaschio CJ, Porto PSDS. Tangential effluent inlet in a cylindrical electrocoagulation reactor containing curved electrodes, and its use in crude oil in water treatment. ENVIRONMENTAL TECHNOLOGY 2022; 43:3559-3569. [PMID: 33913794 DOI: 10.1080/09593330.2021.1924866] [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: 02/09/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
A continuous electrocoagulation reactor, with curved electrodes, polarity switch, and cylindrical geometry, was used for emulsified crude oil in water separation. Apparatus novelty consists of an inlet arranged to promote a circular flow regime. The effects of flow rate (2 and 6 mL.s-1), electrical current (2 and 4 A), and distance between electrodes (1.5 and 2.5 cm) were investigated using a full factorial design and statistical analysis. Using 6 mL.s-1 flow rate, 2 A electric current and 2.5 cm electrode distance; 86% oil removal was obtained at a pH < 9.0. For this configuration, the system will process 21.6 L of oily emulsion while consuming 6.92 Wh. Oil removal increased with flow rate, a novel characteristic created by the unusual geometry of the system.
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Affiliation(s)
- Domênico Andreatta
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
| | - Nasibu Samson Shonza
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
| | - Eduardo Perini Muniz
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
- Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
| | - Marcelo Silveira Bacelos
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
- Departamento de Engenharias e Tecnologia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
| | | | - Paulo Sérgio da Silva Porto
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
- Departamento de Engenharias e Tecnologia, Universidade Federal do Espírito Santo, Rodovia Governador Mario Covas, São Mateus, ES, Brasil
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4
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Das PP, Sharma M, Purkait MK. Recent progress on electrocoagulation process for wastewater treatment: A review. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Shonza NS, Andreatta D, Muniz EP, Dalmaschio CJ, de Freitas RR, Porto PSDS. Crude oil wastewater treatment by electrocoagulation in a continuous process with polarity switch. ENVIRONMENTAL TECHNOLOGY 2022; 43:1700-1708. [PMID: 33151813 DOI: 10.1080/09593330.2020.1847205] [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: 09/03/2020] [Accepted: 10/23/2020] [Indexed: 06/11/2023]
Abstract
The influence of the distance between electrodes, electrical current, and flow rate of emulsified crude oil in water effluent through an electrocoagulation reactor was studied. Power switch at an interval of 30 s was used to reduce electrode passivation. The output variables were power consumption, pH, and oil removal from effluent. There was no significant change in the output variables with the working time of the reactor. The final pH was between 7.5 and 9.5 depending on the input variables. It increases with higher electrical current and tends to decrease with increased flow rate. Increasing electrical current tends to increase while increasing either distance between electrodes or the flow rate tends to reduce oil removal. Using a 2.88 L reactor, it is possible to treat 7.12 L of effluent in one hour, removing 78% of the crude oil, keeping final pH at 8.3, and this system will have an energy consumption of 21.6 kWh.
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Affiliation(s)
- Nasibu Samson Shonza
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, Brasil
| | - Domênico Andreatta
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, Brasil
| | - Eduardo Perini Muniz
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, Brasil
- Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, São Mateus, Brasil
| | | | - Rodrigo Randow de Freitas
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, Brasil
- Departamento de Engenharias e Tecnologia, Universidade Federal do Espírito Santo, São Mateus, Brasil
| | - Paulo Sérgio da Silva Porto
- Programa de Pós-graduação em Energia, Universidade Federal do Espírito Santo, São Mateus, Brasil
- Departamento de Engenharias e Tecnologia, Universidade Federal do Espírito Santo, São Mateus, Brasil
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Hendaoui K, Trabelsi-Ayadi M, Ayari F. Optimization of continuous electrocoagulation-adsorption combined process for the treatment of a textile effluent. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2020.10.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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7
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Ling LC, Buthiyappan A, Abdul Raman AA, Abdul Jabar NH, Singh R. Performance investigation of electrocoagulation and Electro-Fenton processes for high strength landfill leachate: operational parameters and kinetics. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-021-02052-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Influence of methylated milk casein flocculant dosage on removal rate of oil droplet removal from o/w in flotation. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107584] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Treatment of Saline Water Using Electrocoagulation with Combined Electrical Connection of Electrodes. Processes (Basel) 2019. [DOI: 10.3390/pr7050242] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
Saline water treatment has become increasingly important for drinking water supplies. The aim of this study was to evaluate the ability of the electrocoagulation (EC) process with combined aluminum electrodes in removing various types of salt from water samples collected at Sawa Lake, Al-Muthanna, Iraq. The targeted types of salt include total dissolved solids (TDS), chloride salt (Cl−), bromine (Br−), and sulphate (SO42−). A bench scale consisting of combined EC configurations with static electrodes was employed under combined electrical connections. The effect of the six variables factors, such as applied current density (I), reaction time (RT), pH, temperature (T), stirring speed (Mrpm) and inter electrode distance (IED) were observed to achieve a higher removal of TDS, Cl−, Br− and SO42−. Initial results showed the following optimum operating conditions: I = 2 mA/cm2, RT = 80 min, pH = 8, T = 25 °C, IED = 1 cm and Mrpm = 500. The maximum removal efficiency of TDS, Cl−, Br− and SO42− were 91%, 93%, 92% and 90%, respectively. It can be concluded that the EC method applied in the present study was effective to removing salts from lake water.
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Jiang WM, Chen YM, Chen MC, Liu XL, Liu Y, Wang T, Yang J. Removal of emulsified oil from polymer-flooding sewage by an integrated apparatus including EC and separation process. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.09.069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Changmai M, Pasawan M, Purkait M. Treatment of oily wastewater from drilling site using electrocoagulation followed by microfiltration. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.08.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Jiang W, Chen M, Yang J, Deng Z, Liu Y, Bian J, Du S, Hou D. Dynamic experimental study of a new electrocoagulation apparatus with settlement scheme for the removal process in oilfield. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2017.07.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Liu Y, Jiang WM, Yang J, Li YX, Chen MC, Li JN. Experimental study on evaluation and optimization of tilt angle of parallel-plate electrodes using electrocoagulation device for oily water demulsification. CHEMOSPHERE 2017; 181:142-149. [PMID: 28437739 DOI: 10.1016/j.chemosphere.2017.03.141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/22/2017] [Accepted: 03/25/2017] [Indexed: 06/07/2023]
Abstract
Tilt angle of parallel-plate electrodes (APE) is very important as it improves the economy of diffusion controlled Electrocoagulation (EC) processes. This study aimed to evaluate and optimize APE of a self-made EC device including integrally rotary electrodes, at a fixed current density of 120 Am-2. The APEs investigated in this study were selected at 0°, 30°, 45°, 60°, 90°, and a special value (α(d)) which was defined as a special orientation of electrode when the upper end of anode and the lower end of cathode is in a line vertical to the bottom of reactor. Experiments were conducted to determine the optimum APE for demulsification process using four evaluation indexes, as: oil removal efficiency in the center between electrodes; energy consumption and Al consumption, and besides, a novel universal evaluation index named as evenness index of oil removal efficiency employed to fully reflect distribution characteristics of demulsification efficiency. At a given plate spacing of 4 cm, the optimal APE was found to be α(d) because of its potential of enhancing the mass transfer process within whole EC reactor without addition, external mechanical stirring energy, and finally the four evaluation indexed are 97.07%, 0.11 g Al g-1 oil, 2.99 kwhkg-1 oil, 99.97% and 99.97%, respectively.
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Affiliation(s)
- Yang Liu
- Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao Key Laboratory of Circle Sea Oil & Gas Storage and Transportation Technology, Qingdao 266580, China; College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Wen-Ming Jiang
- Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao Key Laboratory of Circle Sea Oil & Gas Storage and Transportation Technology, Qingdao 266580, China; College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China.
| | - Jie Yang
- Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao Key Laboratory of Circle Sea Oil & Gas Storage and Transportation Technology, Qingdao 266580, China; College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Yu-Xing Li
- Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao Key Laboratory of Circle Sea Oil & Gas Storage and Transportation Technology, Qingdao 266580, China; College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Ming-Can Chen
- Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, Qingdao Key Laboratory of Circle Sea Oil & Gas Storage and Transportation Technology, Qingdao 266580, China; College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China
| | - Jian-Na Li
- Thermal Energy Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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Liu Y, Li Y, Jiang W, Chen M, Yang J, Li J. Quantitative analysis on removal path of emulsified oil in the reactor of EC. Sep Purif Technol 2017. [DOI: 10.1016/j.seppur.2017.01.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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An C, Huang G, Yao Y, Zhao S. Emerging usage of electrocoagulation technology for oil removal from wastewater: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:537-556. [PMID: 27865526 DOI: 10.1016/j.scitotenv.2016.11.062] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 06/06/2023]
Abstract
Electrocoagulation is a simple and efficient treatment method involving the electrodissolution of sacrificial anodes and formation of hydroxo-metal products as coagulants, while the simultaneous production of hydrogen at the cathode facilitates the pollutant removal by flotation. Oil is one of the most important hydrocarbon products in the modern world. It can cause environmental pollution during various stages of production, transportation, refining and use. Electrocoagulation treatment is particularly effective for destabilization of oil-in-water emulsions by neutralizing charges and bonding oil pollutants to generated flocs and hydrogen bubbles. The development of electrocoagulation technologies provided a promising alternative for oil removal from wastewater. This paper presents a review of emerging electrochemical technologies used for treating oil-containing wastewater. It includes a brief description of the oily wastewater origin and characteristics. The treatment processes developed so far for oily wastewater and the electrocoagulation mechanisms are also introduced. This paper summarizes the current applications of electrocoagulation for oil removal from wastewater. The factors that influence the electrocoagulation treatment efficiencies as well as the process optimization and modeling studies are discussed. The state-of-the-art and development trends of electrocoagulation process for oil removal are further introduced.
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Affiliation(s)
- Chunjiang An
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada; Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada
| | - Gordon Huang
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada; Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada.
| | - Yao Yao
- Faculty of Engineering and Applied Science, University of Regina, Regina S4S 0A2, Canada
| | - Shan Zhao
- Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina S4S 0A2, Canada
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Efficient demulsification of oil-in-water emulsions using a zeolitic imidazolate framework: Adsorptive removal of oil droplets from water. J Colloid Interface Sci 2016; 478:97-106. [DOI: 10.1016/j.jcis.2016.05.057] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 11/22/2022]
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18
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He CC, Hu CY, Lo SL. Evaluation of sono-electrocoagulation for the removal of Reactive Blue 19 passive film removed by ultrasound. Sep Purif Technol 2016. [DOI: 10.1016/j.seppur.2016.03.047] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Control of Electrocoagulation Batch Reactor for Oil removal from Automobile Garage Wastewater. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.protcy.2016.05.136] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Garg KK, Prasad B. Electrochemical treatment of benzoic acid (BA) from aqueous solution and optimization of parameters by response surface methodology (RSM). J Taiwan Inst Chem Eng 2015. [DOI: 10.1016/j.jtice.2015.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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21
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Lin KYA, Yang H, Petit C, Chen SY. Removal of oil droplets from water using carbonized rice husk: enhancement by surface modification using polyethylenimine. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:8316-28. [PMID: 25529491 DOI: 10.1007/s11356-014-3961-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 12/04/2014] [Indexed: 05/26/2023]
Abstract
Carbonized rice husk (CRH) is a promising material to separate oil from water owing to its abundance, low-cost, and environmentally benign characteristics. However, CRH's performance is somewhat limited by its similar surface charge to that of oil, leading to repulsive interactions. To improve the separation efficiency of CRH, CRH was modified via impregnation with a cationic biocompatible polymer, polyethlyenimine (PEI) to form PEI-CRH. The modified sample exhibits a remarkably higher (10-50 times) oil/water (O/W) separation efficiency than that of the unmodified one. Small PEI-CRH particles (about 64 μm) are found to adsorb oil droplets faster and larger quantities than bigger particles (about 113 and 288 μm). PEI-CRH exhibits higher separation efficiency at high temperatures owing to the destabilization of the emulsion. It is also found that the oil adsorption mechanism involves a chemical interaction between PEI-CRH and oil droplets. The addition of NaCl considerably improves the separation efficiency, while the addition of a cationic surfactant has the opposite effect. In acidic emulsions, PEI-CRH adsorbs more oil than in neutral or basic conditions owing to favorable attractive forces between oil droplets and the surface of PEI-CRH. PEI-CRH can be easily regenerated by washing with ethanol. These promising features of PEI-CRH indicate that PEI-CRH could be an efficient and low-cost adsorbent for the O/W separation applications.
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Affiliation(s)
- Kun-Yi Andrew Lin
- Department of Environmental Engineering, National Chung Hsing University, 250 Kuo- Kuang Road, Taichung, Taiwan, Republic of China,
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22
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Raschitor A, Fernandez CM, Cretescu I, Rodrigo MA, Cañizares P. Sono-electrocoagulation of wastewater polluted with Rhodamine 6G. Sep Purif Technol 2014. [DOI: 10.1016/j.seppur.2014.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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El Naggar AMA, Noor El-Din MR, Mishrif MR, Nassar IM. Highly Efficient Nano-Structured Polymer-Based Membrane/Sorbent for Oil Adsorption from O/W Emulsion Conducted of Petroleum Wastewater. J DISPER SCI TECHNOL 2014. [DOI: 10.1080/01932691.2014.888520] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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24
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Can OT, Bayramoglu M. A Comparative Study on the Structure–Performance Relationships of Chemically and Electrochemically Coagulated Al(OH)3 Flocs. Ind Eng Chem Res 2014. [DOI: 10.1021/ie402789w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Orhan Taner Can
- Bitlis Eren University, Department of Environmental
Engineering, 13000 Bitlis, Turkey
| | - Mahmut Bayramoglu
- Gebze Institute of Technology, Department of Chemical
Engineering, Cayirova, 41400 Gebze, Turkey
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Khosa MK, Jamal MA, Hussain A, Muneer M, Zia KM, Hafeez S. Efficiency of Aluminum and Iron Electrodes for the Removal of Heavy Metals [(Ni (II), Pb (II), Cd (II)] by Electrocoagulation Method. JOURNAL OF THE KOREAN CHEMICAL SOCIETY-DAEHAN HWAHAK HOE JEE 2013. [DOI: 10.5012/jkcs.2013.57.3.316] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Mechelhoff M, Kelsall GH, Graham NJ. Electrochemical behaviour of aluminium in electrocoagulation processes. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2013.03.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Modelling and cost evaluation of electro-coagulation processes for the removal of anions from water. Sep Purif Technol 2013. [DOI: 10.1016/j.seppur.2013.01.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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28
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Sangal VK, Mishra IM, Kushwaha JP. Electrocoagulation of Soluble Oil Wastewater: Parametric and Kinetic Study. SEP SCI TECHNOL 2013. [DOI: 10.1080/01496395.2012.719985] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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29
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Secula MS, Cagnon B, de Oliveira TF, Chedeville O, Fauduet H. Removal of acid dye from aqueous solutions by electrocoagulation/GAC adsorption coupling: Kinetics and electrical operating costs. J Taiwan Inst Chem Eng 2012. [DOI: 10.1016/j.jtice.2012.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Maruyama H, Seki H, Satoh Y. Removal kinetic model of oil droplet from o/w emulsion by adding methylated milk casein in flotation. WATER RESEARCH 2012; 46:3094-3100. [PMID: 22483713 DOI: 10.1016/j.watres.2012.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 02/22/2012] [Accepted: 03/10/2012] [Indexed: 05/31/2023]
Abstract
In this study, o/w emulsion flotation experiments were conducted by adding methylated milk casein (MeSC). Emulsion used in this study was prepared by ultrasonic emulsification of heavy oil (bunker-A) and sodium dodecyl sulfate (SDS) solution. A simple kinetic model was proposed to estimate the removal rate of the oil droplets within the column. The model was based on main assumption that adsorption of single droplet adsorbed MeCS or floc onto bubble surface within flotation column. Removal rate constant, K, was defined by k(a)X(s) (S(b)τ/V), where k(a) and X(s) are overall adsorption rate and saturated adsorption density of oil droplet or floc, S(b), τ and V are bubble surface production rate, retention time of bubble swarms and emulsion volume within the column, respectively. The experiments were conducted with varying operating conditions; superficial gas velocity, column dimension and emulsion volume. K was evaluated from slope value of obtained straight line by plotting time versus ln (T/T(0)), where T/T(0) is relative turbidity. K was mostly proportional to (S(b)τ/V), which corresponds to specific surface area of bubble swarms per unit volume within the column, in the present experimental region. This result suggested that efficiency of this removal process was mainly controlled by the specific surface area of bubble swarms, and proposed model was fundamentally verified.
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Affiliation(s)
- Hideo Maruyama
- Division of Marine Biosciences, Graduate School of Fisheries Sciences, Hokkaido University, Minato 3-1-1, Hakodate 041-8611, Japan.
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31
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Purification of firefighting water containing a fluorinated surfactant by reverse osmosis coupled to electrocoagulation–filtration. Sep Purif Technol 2011. [DOI: 10.1016/j.seppur.2010.10.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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32
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Rodrigo M, Cañizares P, Buitrón C, Sáez C. Electrochemical technologies for the regeneration of urban wastewaters. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.01.053] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Wang H, Xu R, Li F, Qiao J, Zhang B. Efficient degradation of lube oil by a mixed bacterial consortium. J Environ Sci (China) 2010; 22:381-388. [PMID: 20614780 DOI: 10.1016/s1001-0742(09)60119-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A laboratory study was performed to assess the biodegradation of lube oil in bio-reactor with 304# stainless steel as a biofilm carrier. Among 164 oil degrading bacterial cultures isolated from oil contaminated soil samples, Commaonas acidovorans Pxl, Bacillus sp. Px2, Pseudomonas sp. Px3 were selected to prepare a mixed consortium for the study based on the efficiency of lube oil utilization. The percentage of oil degraded by the mixed bacterial consortium decreased slightly from 99% to 97.2% as the concentration of lube oil was increased from 2000 to 10,000 mg/L. The degradation of TDOC (total dissolved organic carbon) showed a similar tendency compared with lube oil removal, which indicated that the intermediates in degradation process hardly accumulated. Selected mixed bacterial consortium showed their edge compared to activated sludge. Scanning electron microscopy (SEM) photos showed that biofilms on stainless steel were robust and with a dimensional framework constructed by EPS (extracellular polymeric substances), which could promote the biodegradation of hydrocarbons. The increase of biofilm followed first-order kinetics with rate of 0.216 microg glucose/(cm2-day) in logarithm phase. With analysis of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) combined with removal of lube oil and TDOC, mixed bacterial consortium could degrade benzene and its derivatives, aromatic ring organic matters with a percentage over 97%.
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Affiliation(s)
- Haifeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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34
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Ben Sasson M, Calmano W, Adin A. Iron-oxidation processes in an electroflocculation (electrocoagulation) cell. JOURNAL OF HAZARDOUS MATERIALS 2009; 171:704-709. [PMID: 19577360 DOI: 10.1016/j.jhazmat.2009.06.057] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 06/11/2009] [Accepted: 06/12/2009] [Indexed: 05/28/2023]
Abstract
The processes of iron oxidation in an electroflocculation cell were investigated for a pH range of 5-9 and electric currents of 0.05-0.4A (equivalent current densities of 8.6-69 A/m(2)). At all pH values and electric currents investigated, it was demonstrated and proven that for all practical purposes, the form of iron that dissolves from the anode is Fe(2+) (ferrous). The difference between the amount of theoretical dissolution as calculated by Faraday's law and the amount of observed dissolved iron ions may indicate two phenomena in electrochemical cells. The first is possible dissolution of the anode even without the operation of an electric current; this led to higher theoretical dissolution rates at lower pH. The second is the participation of some of the electrons of the electric current in reactions other than anode dissolution which led to lower theoretical dissolution rates at higher pH. Those other reactions did not lead to an increase in the local oxidation saturation level near the anode and did not affect iron-oxidation rates in the electroflocculation processes. The oxidation rates of the dissolved Fe(2+) (ferrous) to Fe(3+) (ferric) ions in electroflocculation processes were strongly dependent on the pH and were similar to the known oxidation rates of iron in non-electrochemical cells.
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Affiliation(s)
- Moshe Ben Sasson
- The Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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35
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Robić G, Miranda EA. Modeling of protein and phenolic compound removal from aqueous solutions by electrocoagulation. Biotechnol Prog 2009; 26:186-91. [DOI: 10.1002/btpr.308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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36
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Zodi S, Potier O, Lapicque F, Leclerc JP. Treatment of the textile wastewaters by electrocoagulation: Effect of operating parameters on the sludge settling characteristics. Sep Purif Technol 2009. [DOI: 10.1016/j.seppur.2009.06.028] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Abdelwahab O, Amin NK, El-Ashtoukhy ESZ. Electrochemical removal of phenol from oil refinery wastewater. JOURNAL OF HAZARDOUS MATERIALS 2009; 163:711-716. [PMID: 18755537 DOI: 10.1016/j.jhazmat.2008.07.016] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Revised: 05/12/2008] [Accepted: 07/04/2008] [Indexed: 05/26/2023]
Abstract
This study explores the possibility of using electrocoagulation to remove phenol from oil refinery waste effluent using a cell with horizontally oriented aluminum cathode and a horizontal aluminum screen anode. The removal of phenol was investigated in terms of various parameters namely: pH, operating time, current density, initial phenol concentration and addition of NaCl. Removal of phenol during electrocoagulation was due to combined effect of sweep coagulation and adsorption. The results showed that, at high current density and solution pH 7, remarkable removal of 97% of phenol after 2h can be achieved. The rate of electrocoagulation was observed to increase as the phenol concentration decreases; the maximum removal rate was attained at 30 mg L(-1) phenol concentration. For a given current density using an array of closely packed Al screens as anode was found to be more effective than single screen anode, the percentage phenol removal was found to increase with increasing the number of screens per array. After 2h of electrocoagulation, 94.5% of initial phenol concentration was removed from the petroleum refinery wastewater. Energy consumption and aluminum Electrode consumption were calculated per gram of phenol removed. The present study shows that, electrocoagulation of phenol using aluminum electrodes is a promising process.
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Affiliation(s)
- O Abdelwahab
- Environmental Division, National Institute of Oceanography and Fisheries, Kayet Bay, El-Anfushy, Alexandria, Egypt.
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38
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Emamjomeh MM, Sivakumar M. Review of pollutants removed by electrocoagulation and electrocoagulation/flotation processes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2009; 90:1663-1679. [PMID: 19181438 DOI: 10.1016/j.jenvman.2008.12.011] [Citation(s) in RCA: 211] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 11/23/2008] [Accepted: 12/11/2008] [Indexed: 05/27/2023]
Abstract
The word "electrocoagulation" (EC) will be sometimes used with "electroflotation" (EF) and can be considered as the electrocoagulation/flotation (ECF) process. Through the process of electrolysis, coagulating agents such as metal hydroxides are produced. When aluminium electrodes are used, the aluminium dissolves at the anode and hydrogen gas is released at the cathode. The coagulating agent combines with the pollutants to form large size flocs. As the bubbles rise to the top of the tank they adhere to particles suspended in the water and float them to the surface. In fact, a conceptual framework of the overall ECF process is linked to coagulant generation, pollutant aggregation, and pollutant removal by flotation and settling when it has been applied efficiently to various water and wastewater treatment processes. This review paper considers a significant number of common applications of EC and ECF processes which have been published in journal and conference papers.
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Affiliation(s)
- Mohammad M Emamjomeh
- Environmental Health Engineering Group, Faculty of Health, Qazvin University of Medical Sciences, Qazvin, Iran.
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39
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Maruyama H, Tada Y, Seki H. Enhancement of oil droplet removal from o/w emulsion by adding methylated milk casein in flotation technique. ASIA-PAC J CHEM ENG 2009. [DOI: 10.1002/apj.223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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40
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Removal of Biorefractory Compounds in Industrial Wastewater by Chemical and Electrochemical Pretreatments. Ind Eng Chem Res 2008. [DOI: 10.1021/ie800560n] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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41
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Kobya M, Ciftci C, Bayramoglu M, Sensoy M. Study on the treatment of waste metal cutting fluids using electrocoagulation. Sep Purif Technol 2008. [DOI: 10.1016/j.seppur.2007.09.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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42
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Cañizares P, Martínez F, Jiménez C, Sáez C, Rodrigo MA. Coagulation and electrocoagulation of oil-in-water emulsions. JOURNAL OF HAZARDOUS MATERIALS 2008; 151:44-51. [PMID: 17583426 DOI: 10.1016/j.jhazmat.2007.05.043] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 05/11/2007] [Accepted: 05/14/2007] [Indexed: 05/15/2023]
Abstract
In this work the efficiencies of the chemical and the electrochemical break-up of oil-in-water (O/W) emulsions with hydrolyzing aluminium salts are compared. It has been obtained that the efficiency of the processes does not depend directly on the dosing technology, but on the total concentration of aluminium and pH. This latter parameter changes in a different way in the chemical and the electrochemical processes: the pH increases during the electrochemical experiments since the electrochemical system leads to the formation of aluminum hydroxide as a net final product, but it decreases in the conventional ones due to the acid properties of the aluminum salts added (AlCl3 or Al2(SO4)3). The break-up of the emulsions only takes place in the range of pHs between 5 and 9, and the amount of aluminium necessary to produce the destabilization of the emulsion is proportional to the oil concentration. Electrolytes containing chlorides improve COD removal as compared with those containing sulphate ions. Aluminium hydroxide precipitates were found to be the primary species present in solution in the conditions in which the breaking process is favoured. Consequently, the attachment of more than one droplet of oil at a time to a charged precipitate-particle (bridging flocculation) was proposed as the primary destabilization mechanism.
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Affiliation(s)
- Pablo Cañizares
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
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43
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Kobya M, Bayramoglu M, Eyvaz M. Techno-economical evaluation of electrocoagulation for the textile wastewater using different electrode connections. JOURNAL OF HAZARDOUS MATERIALS 2007; 148:311-8. [PMID: 17368931 DOI: 10.1016/j.jhazmat.2007.02.036] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Revised: 02/12/2007] [Accepted: 02/13/2007] [Indexed: 05/14/2023]
Abstract
The bench scale of an electrocoagulation (EC) unit requires a detailed study discerning the effects of continuous variables such as pH, current density and operating time, and type variables such as electrode material and connection mode. This paper presents the results of the treatment of a textile wastewater by EC process. Two electrode materials, aluminum and iron, were connected in three modes namely, monopolar-parallel (MP-P), monopolar-serial (MP-S), and bipolar-serial (BP-S). COD and turbidity removals were selected as performance criteria. For a high COD removal, acidic medium is preferable for both electrode materials. For a high turbidity removal, acidic medium is preferable for aluminum, and neutral medium for iron. High current density is favorable for both removals in the case of iron. In the aluminum case, the current density exhibits a pronounced effect on COD removal, depending strongly on the connection mode, but it has a negligible effect on the turbidity removal. MP-P with iron or MP-S with aluminum electrode are suitable configurations in regard with the overall process performance. Moreover, process economy is as important as removal efficiencies during the process evaluation task. Various direct and indirect cost items including electrical, sacrificial electrodes, labor, sludge handling, maintenance and depreciation costs have been considered in the calculation of the total cost. The results show that MP-P mode is the most cost-effective for both electrode types. Both electrodes show similar results in reducing COD and turbidity, but iron is preferred as a low cost material. Finally, a comparative study showed that EC was faster and more economic; consumed less material and produced less sludge, and pH of the medium was more stabilized than chemical coagulation (CC) for similar COD and turbidity removal levels. For CC, FeCl(3) was the preferable salt in view of its techno-economic performance. On the other hand, iron was the preferred electrode material in EC with MP-P system in experimental conditions such as, 30 Am(-2) of current density and 15 min of time, the treatment cost was $ 0.245 m(-3). Consequently, the operating cost of CC was 3.2 times as high as the operating cost of EC.
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Affiliation(s)
- Mehmet Kobya
- Department of Environmental Engineering, Gebze Institute of Technology, Gebze, Turkey.
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44
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Cañizares P, Jiménez C, Martínez F, Sáez C, Rodrigo MA. Study of the Electrocoagulation Process Using Aluminum and Iron Electrodes. Ind Eng Chem Res 2007. [DOI: 10.1021/ie070059f] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pablo Cañizares
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
| | - Carlos Jiménez
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
| | - Fabiola Martínez
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
| | - Cristina Sáez
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
| | - Manuel A. Rodrigo
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13005 Ciudad Real, Spain
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45
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46
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Golder AK, Chanda AK, Samanta AN, Ray S. Removal of Cr(VI) from Aqueous Solution: Electrocoagulation vs Chemical Coagulation. SEP SCI TECHNOL 2007. [DOI: 10.1080/01496390701446464] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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47
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Harif T, Adin A. Characteristics of aggregates formed by electroflocculation of a colloidal suspension. WATER RESEARCH 2007; 41:2951-61. [PMID: 17524446 DOI: 10.1016/j.watres.2006.11.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 11/06/2006] [Accepted: 11/08/2006] [Indexed: 05/15/2023]
Abstract
Electroflocculation (EF) is becoming recognized as an alternative process to conventional coagulation/flocculation, although both are somewhat different. The electrical current applied in EF to generate the active coagulant species creates a unique chemical/physical environment which affects coagulation mechanisms and subsequent aggregate formation. The chemical and physical characteristics of an electroflocculated kaolin suspension and the morphology/fractal dimension of the resulting aggregates were examined. An EF cell was operated in batch mode and comprised of two concentric electrodes--a stainless steel cathode (outer electrode) and an aluminum anode (inner electrode). The cell was run at constant current between 0.05 and 0.3A, velocity gradients were 0-30s(-1). The results show that the simultaneous hydrolysis occurring has a profound effect on the final pH and consequently on the coagulation mechanisms as indicated by differences in zeta potential measured. Moreover, the electrical field induced by passage of a current has an apparent effect on particle transport. A linear correlation between floc size and current was observed and lower fractal dimensions were obtained for larger floc sizes. The fractal dimensions of the flocs obtained in EF are on average lower than those reported for conventional coagulation.
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Affiliation(s)
- T Harif
- Soil and Water Sciences Department, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, POB 12, Rehovot 71612, Israel.
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48
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Cañizares P, Martínez F, Jiménez C, Lobato J, Rodrigo MA. Coagulation and Electrocoagulation of Wastes Polluted with Colloids. SEP SCI TECHNOL 2007. [DOI: 10.1080/01496390701446530] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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49
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Cañizares P, Martínez F, Lobato J, Rodrigo MA. Break-up of oil-in-water emulsions by electrochemical techniques. JOURNAL OF HAZARDOUS MATERIALS 2007; 145:233-40. [PMID: 17196330 DOI: 10.1016/j.jhazmat.2006.11.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Revised: 05/17/2006] [Accepted: 11/12/2006] [Indexed: 05/13/2023]
Abstract
Electrochemically-assisted technologies can be successfully applied to the treatment of oil-in-water (O/W) emulsions. In this work, it is studied the influence of the main parameters (electrical charge passed, pH, electrolyte, oil content and operation mode) in the efficiency of these processes, when aluminium electrodes are used. The pH was found to be the most significant parameter, and good removal efficiencies were only obtained for pHs in the range 5-9. The electrical charge passed was observed to be directly related to the aluminium supplied to the waste. For a given oil concentration it is required that a minimum electrical charge is passed to break-up the emulsion. Further increases in the electrical charge lead to increase in the COD removal. The influence of the oil concentration is related to that of the electrical charge passed: for a given dose of aluminium, the higher the oil content the lower the COD-removal efficiency. Likewise, to produce the break-up of the emulsion it is required a minimum dose of aluminium (electrical charge passed), lower doses do not attain the rupture of the emulsion. The type of electrolyte and its concentration were also found to influence the process efficiency. Better efficiencies were obtained in the treatment of chloride-containing wastes and for low concentration of electrolyte. The destabilization of the O/W emulsion was found to be favoured in the discontinuous operation mode. Bridging flocculation is a primary destabilization mechanism that can explain the experimental results obtained in this work.
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Affiliation(s)
- Pablo Cañizares
- Department of Chemical Engineering, Facultad de Ciencias Químicas, Universidad de Castilla La Mancha, Campus Universitario s/n, 13071 Ciudad Real, Spain
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50
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