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Materials Involved in Electrocoagulation Process for Industrial Effluents
Published in Mu Naushad, Saravanan Rajendran, Abdullah M. Al-Enizi, New Technologies for Electrochemical Applications, 2020
Carlos Navas-Cárdenas, Herman Murillo, Maibelin Rosales, Cesar Ron, Florinella Muñoz
In this context, electrochemical methods such as electrocoagulation (EC), electrooxidation, electroflotation, and photo-assisted electrochemical methods have been emerging as alternatives of wastewater treatment, and are based on the use of electrons as the working agents to promote the pollutant removal (Brillas and Martínez-Huitle 2015; Moussa et al. 2017; Yavuz and Ogütveren 2018). Among the electrochemical methods, EC is one of the most promising water treatment technologies employed to remove refractory pollutants from industrial effluents. The EC process involves electrochemical reactions to lead the in situ formation of coagulating agents by the electrodissolution of a sacrificial anode due to the applied electric field to the electrodes (Aljaberi 2018; Chen 2004; Meas et al. 2010). The advantages of EC over conventional wastewater treatments include high removal efficiency, use of less or no chemicals, compact treatment facilities, relatively low cost, lower amount sludge production, and the possibility of complete automation (An et al. 2017; Jiang et al. 2017; Kobya et al. 2011).
Hydrometallurgy
Published in C. K. Gupta, Extractive Metallurgy of Molybdenum, 2017
The electrooxidation process has been extensively investigated for processing gold, silver, antimony, mercury, and molybdenum source materials. Electrolytic cells of various types, characterized by different configurations of the electrode systems and different types of electrode connections, have been used in electrooxidation. Tubular-type and plate-type laboratory scale electrooxidation cells are illustrated in Figure 11. These are simple monopolar systems in which the anodes and cathodes are connected in parallel and each electrode is attached to the corresponding bus bar. These cells are suitable for the evaluation of the electrolytic oxidation concept. They, however, present serious problems with regard to industrial scale operations. The high amperage-low voltage rectifiers and the attendent largesized bus bars are costly. Moreover, because of their bulk, they lead to design and operational problems. These disadvantages are overcome when a bipolar cell is used. In a bipolar system, the two end electrodes only are connected to the direct current source, the intermediate electrodes having no direct electrical connection to the bus bars. During electrolysis, the intermediate electrodes become bipolar and assume opposite charges on either side. Each adjacent pair of electrodes acts as an individual cell connected in series with any other adjacent pair. As a result of this configuration, the voltage and the hypochlorite production rate are increased roughly (n − 1) times the number of electrodes as compared with the monopolar arrangement. A bipolar system requires a higher voltage, but a correspondingly lower amperage vis à vis a monopolar cell system. The net result saves space, minimizes the size of bus bars, and simplifies the rectifier needs. Ideally, in the operation of a bipolar cell, current passes from the end electrode through each intermediate electrode in sequence. The arrangement of electrodes for bipolar cell operation is illustrated in Figure 12.
Treatment of tequila distillation volatile residues by electrochemical oxidation using titanium electrodes
Published in Environmental Technology, 2023
Edgardo Martínez-Orozco, Juan Nápoles-Armenta, Pablo Gortáres-Moroyoqui, Norberto Santiago-Olivares, Ruth Gabriela Ulloa-Mercado, Celia De la Mora-Orozco, Luis Alonso Leyva-Soto, Luis Humberto Alvarez-Valencia, Edna Rosalba Meza-Escalante, Ana María Rentería-Mexia
Electrochemical oxidation, or electrooxidation (EO), can generate OH radicals with electrical energy able to oxidise several organic compounds and be used for their removal [10]. Electrochemical oxidation has proven effective in contaminant removal [11]. Asokan and Krishnan [12] reported ethanol reduction content by electrochemical oxidation using 0.5 mol/dm3 in an acid solution with 0.5 mol/dm3 sulphuric acid. Johnson and Kumar [13], using distillery wastewater with 150,000.00 COD mg/L, an electrical current of 0.5 A with Ti/Ti-RuO2 electrode separation of 0.5 cm reached a 52.3% COD reduction in 14 h, considering electrode polarisation in this time. Álvarez-Pugliese et al. [14] achieved an 80% COD removal with energy consumption below 50 kWh/m3 using boron-doped diamond (BDD) electrodes. Martinez et al. [15] reported a 90% COD removal with BBD with 17 kWh/kg. Vilar et al. [16] reported 50.8% COD removal with 25 mA/cm2 using a NaCl concentration of 0.025 M with BDD and a dimensionally steady anode (DSA).
The application of electrochemical processes in oily wastewater treatment: a review
Published in Journal of Environmental Science and Health, Part A, 2021
Morana Druskovic, Drazen Vouk, Hana Posavcic, Ivan Halkijevic, Karlo Nad
Electrochemical methods (electrooxidation, electroreduction, electrocoagulation) are of special interest because they are insensitive to toxic and inhibitory substances, have non-uniform composition and hydraulic loads of raw wastewater, have a high potential for the degradation of phenolic compounds, do not depend on temperature changes of the raw wastewater, do not require dilution as well as the addition of chemicals, since the products needed for wastewater treatment are generated electrochemically in the reaction vessel. In addition, electrochemical methods do not require pH adjustment during processing and do not increase the concentration of soluble matter in the effluent.[37] In this paper, the focus is on the electrochemical advanced oxidation (AOP) processes and electrocoagulation (EC) methods. Some studies show the high efficiency of EC process in treating oily wastewater, Table 2.[16,19,25,36,38]
Conventional and advanced treatment technologies for palm oil mill effluents: a systematic literature review
Published in Journal of Dispersion Science and Technology, 2021
G. Yashni, Adel Al-Gheethi, Radin Maya Saphira Radin Mohamed, Siti Nor Hidayah Arifin, Siti Nor Aishah Mohd Salleh
Electro-oxidation is also an effectual method for pollutant degradation by using electrochemically produced oxidants or anodic adsorbed oxidants to concurrently perform direct and indirect oxidation.[55] This procedure utilizes electric potential where ionized metallic species are coated on the cathode surface. This procedure needs less chemicals and generates fewer sludge, but the high initial capital cost and costly electricity source reduce its efficiency.[106] Bashir et al.[55] explored electro-oxidation of POME at optimum operational conditions with 45 mA/cm2 of current density, 45 minutes of contact time, pH 4 and 0.892 g of S2O82- and achieved COD removals of 77.70%, color removal of 97.96% and SS removals of 99.72%.