Decolorization of Synthetic and Real Wastewater by Indirect Electrochemical Oxidation Process (original) (raw)
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Electrode material in electrochemical decolorization of dyestuffs wastewater: A review
E3S Web of Conferences, 2021
Tеxtile wastewater contains a variety of contaminants that are known to be hazardous. Synthetic dyes are one of the hazardous pollutants in the textile industry that are resistant to the photo/bio dеgradation. They cannot be dеstroyed under conventional wastewater treatment. This document presents a review on the electrochemical treatment of wastеwater containing synthetic organic dyes by anodic oxidation for environmental protection. The mechanisms of еlectrochemical oxidation in anodic oxidation processes are well explained. A largе number of electrodes have been tested by this method. Therefore, this papеr aims to summarize and discuss the most important and rеcent results available in the literature on anode application for the rеmoval of synthetic dyestuffs. Finally, the prospects of the process for futurе research are suggested.
Parametric Studies on Electrochemical Treatment of Synthetic Wastewater
The present study focuses on effects of operational parameters on electrochemical wastewater treatment for synthetic wastewater. Electro-oxidation has emerged as one of the advanced oxidation processes gaining more attention because it offers many distinctive advantages over other conventional methods such as versatility, high treatment efficiency, safety, amenability of automation and cost effectiveness. In the present work, Reactive Red2 dye was used as model pollutant to prepare synthetic wastewater. Cerium (Ce) based mixed metal oxide electrode prepared by thermal decomposition method was usedas anode andthe effectiveness of the treatment was analyzed on the basis of total organic carbon(TOC)removal and decolorization.
Decolorization of industrial wastewater using electrochemical peroxidation process
Journal of Electrochemical Science and Engineering, 2021
In this study, decolorization of wastewater samples taken from the paper industry is investigated using electrochemical peroxidation process. The electrochemical peroxidation process is a part of electrochemical advanced oxidation processes, which is based on the Fenton’s chemical reaction, provided by addition of external H2O2 into reaction cell. In this study, iron is used as anode and graphite as cathode put at the fixed distance of 30 mm in a glass reaction cell. The cell was filled with the solution containing wastewater and sodium chloride as the supporting electrolyte. Factors of the process such as pH, current intensity, hydrogen peroxide concentration, and time of treatment were studied. The results illustrate that all these parameters affect efficiencies of dye removal and chemical oxygen demand (COD) reducing. The maximal removal of wastewater contaminants was achieved under acid (pH 3) condition, with the applied current of 1 A, and hydrogen peroxide concentration of 0.0...
The degradation of reactive red dye from wastewaters by advanced electrochemical oxidation
Water Pollution XI, 2012
In the present study, electrochemical degradation experiments were conducted to degrade a textile dye namely Reactive Red 147 (RR) from water. The process performance was assessed in terms of the electrochemical decolourisation and mineralization of aqueous RR solutions. Electrolyses were carried out under galvanostatic conditions using boron-doped diamond (BDD) electrodes in 0.1 M Na 2 SO 4 supporting electrolyte using undivided electrolytic cell. Also, the effect of in-situ electrolytic generation of chlorine/hypochlorite at BDD electrode from a mixture of 0.05 M Na 2 SO 4 and 0.05 M NaCl supporting electrolyte on the electrochemical degradation process of RR has been studied. Prior to electrolysis application, the electrochemical behaviour of RR dye on BDD electrode was characterized in both supporting electrolytes without/with chloride presence by cyclic voltammetry in order to establish the working potential-current conditions. The influence of operating variables on the electrochemical process efficiency was studied as a function of the supporting electrolyte type, current density, and the initial pH. Under all applied conditions, the complete decolourisation of dye synthetic solution was achieved after several minutes of electrolysis. Acidic medium and the chlorine/hypochlorite generation favored the decolorization and mineralization process of RR. The complete mineralization of dye synthetic solution was not achieved, and the maximum mineralization efficiency of 35% was reached under the working conditions of hypochlorite presence, which informs about the intermediates generation during the application of electrochemical process based on BDD electrodes.
Decolorization and COD measurements of synthetic wastewater containing acid brown and reactive blue dyes were studied using a batch recycle annular electrochemical reactor. Graphite rod was used as anode while stainless steel screen was used as cathode. The effect of current density, sodium chloride concentration, initial dye concentration, pH and solution flow rate on color removal and COD reduction was evaluated. The results indicate that 100% color removal and 89 % in COD reduction can be achieved under suitable conditions. Energy consumption ranged from 1.2 to 10.4 kWh/kg COD removed depending on the operating conditions. These results recommend considering the present electrochemical oxidation technique to treat wastewater containing dyes.
Remediation of domestic wastewater by electrochemical oxidation of dissolved organic species
Journal of the Iranian Chemical Society, 2020
This study reports on the treatment of wastewater containing dissolved organic matter (DOM). DOM introduces complexing agents, promotes bacterial growth, and affects the color plus taste of water negatively. The normal practice for treatment such pollutants is the use of introduction of oxidizing agents in the water. However, this introduces secondary pollutants to the treated water, and to overcome the challenge, this study has developed an electrochemical method for treating wastewater with no secondary pollutants. A two-chamber electrochemical cell separated by a proton exchange membrane (PEM) was constructed with inert electrodes. The PEM was made from a conducting polymer inert in aqueous media. The anode water was bubbled with air for reduction of oxygen and therefore formation of strong oxidizing agent for the degradation of DOM. The degradation was monitored using Ultraviolet-visible (UV-VIS) spectroscopy as the potential difference across the cell was monitored. There was a significant reduction in the color and the decay followed first-order kinetics, for unimolecular degradation with a constant of 0.0148 min −1. A high potential of 1.25 V was registered within the first 40 min confirming that the degradation was spontaneous making the water safe for consumption. The degradation was confirmed by voltametric method where the concentration of iron within the vegetative matter was observed to increase at a potential of − 0.18 V with time due to the release of the labile metal ions. This shows that the constructed cell has a potential application in the remediation of domestic wastewater at a point of use.
The high energy cost of an electrochemical method is the fatal drawback that hinders its large scale application in wastewater treatment. The traditional single-chamber electrochemical method used in the waste water treatment mainly focused on anodic oxidation, but hydrogen produced on the cathode and indirect electrochemical treatment involves application of an electrical current to the wastewater containing chloride to convert into chlorine/hypochlorite. The two-compartment electrolytic cell, separated by an anion exchange membrane, has been developed in this work. In the new reactor, indirect oxidation at anode, indirect oxidation by hydrogen peroxide and ultraviolet/hydrogen peroxide (UV/H 2 O 2 ) at cathode can occur simultaneously. The electrochemically produced hydrogen peroxide at the cathode by reduction of oxygen is affected by passing atmospheric air. Therefore "dual electrochemical oxidation" in one electrochemical reactor was achieved successfully. Compared to a traditional one-cell reactor, this reactor reduces the energy cost approximately by 25-40%, and thus the present work becomes significant in wastewater treatment. Experiments were carried out at different current densities using Ti/RuO 2 /IrO 2 as anode and carbon felt gas diffusion electrode used as a cathode fed with oxygen containing gases to produce hydrogen peroxide. During the various stages of electrolysis, the parameters such as, effect of pH, chemical oxygen demand (COD), colour, energy consumption were monitored. UV-vis spectrometry, Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC) studies were carried out to assess efficiencies of dye degradation.
Performance of Electrochemical Oxidation in Treating Textile Dye Wastewater by Stainless Steel Anode
Electrochemical oxidation for a textile dye wastewater collected from a textile processing industry was investigated in this study using Stainless Steel an anode. Number of batch experiments was run in a laboratory-scale. The results are reported in terms of percentage removal of Chemical Oxygen Demand (COD), Color and variations in BOD/COD ratio for different current densities of 12, 24 and 48 A/m 2 . For current densities 12, 24 and 48 A/m 2 , COD was reduced by 52%, 63% and 71% respectively; Color was reduced by 41%, 55%, 77% respectively. The biodegradability was improved because of the increase BOD/COD ratio from 0.1 to 0.58. It was observed that increasing the electrolysis time and increased current density bring down the concentration of pollutants. COD removal and energy consumption rates are discussed. Kinetics for COD removal is also discussed. It can be concluded from the results that SS as an anode found to be effective in treating this electrolyte and could be effectively used for pretreatment of textile dye wastewater.
Reduction of Color and COD of Anaerobically Treated Distillary Wastewater by Electrochemical Method
2013
Water pollution control is presently one of the major thrust areas of scientific research. While colored organic compounds generally impart only a minor fraction of the organic load to wastewaters, their color renders them aesthetically unacceptable. Stringent regulating measures are coaxing industries to treat their waste effluents to increasingly high standards. Various studies have been carried out here in reduction of color and COD from anaerobically treated distillery wastewater by electrochemical method which showed a good reduction in color (97-98%) and COD (70-72%). The optimized parameters for the process are Electrode distance 1cm, initial pH 4, current density 2 Amp/dm 2 for 3 hours and color and COD reduction observed are 97.8% and 68% respectively.