Treatment of organic content at high Total Dissolved Solids By Electrochemical Oxidation (original) (raw)
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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.
Chemical Society Reviews, 2006
In recent years, there has been increasing interest in finding innovative solutions for the efficient removal of contaminants from water, soil and air. The present tutorial review summarizes the results of an extensive selection of papers dealing with electrochemical oxidation, which is proposed as an alternative for treating polluted wastes. Both the direct and indirect approaches are considered, and the role of electrode materials is discussed together with that of other experimental parameters.
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.
Electrochemical oxidation of wastewater – opportunities and drawbacks
Water Science and Technology, 2013
Electrochemical oxidation by means of boron-doped diamond (BDD) anodes generates a very efficient oxidizing environment by forming hydroxyl radicals, providing effective water purification for elimination of persistent pollutants. In this project the degradation rates of organic and inorganic substances are investigated. Experiments were performed in laboratory and pilot scale with synthetic and industrial wastewaters. Performance parameters were evaluated in terms of total organic carbon/chemical oxygen demand (COD) removal, specific energy consumption and current efficiency. The integration of this advanced oxidation technology combined with conventional technology was then applied in a wastewater treatment concept of landfill leachate. The raw leachate with a low biochemical oxygen demand/COD ratio was electrochemically oxidized to prepare the purified leachate for discharge into a sewage system or a receiving water body. The cost estimation regarding operation and capital costs ...
Decolorization of Synthetic and Real Wastewater by Indirect Electrochemical Oxidation Process
In this paper the decolorization and degradation of synthetic and real wastewater by electrochemical oxidation method were investigated. Synthetic wastewater consisting of Mordant Red 3 (MR3) was used as a model compound. Electroc-hemical degradation processes were performed using Pt as an anode and Stainless Steel 304 as a cathode. In the bulk solution , the strong oxidizing potential of the chemicals were produced when the wastewater was passed through the elec-trolytic cell the organic pollutants were oxidized to little or harmless organic molecules, carbon dioxide and water. The results indicated that the removal of chemical oxygen demand (COD) and color were 86% and 100% respectively. The removal of COD and color increased by increasing voltage and chloride concentration at low pH.
Indirect Electrochemical Oxidation of Phenol in the Presence of Chloride for Wastewater Treatment
Chemical Engineering & Technology, 2005
Electrochemical oxidation of phenol using a Ti/TiO 2-RuO 2-IrO 2 anode in the presence of chloride as the supporting electrolyte was investigated. The experiments were performed in an undivided batch reactor. Preliminary investigations showed that only a small fraction of phenol was oxidized by direct electrolysis, while complete degradation of phenol was achieved by indirect electrochemical oxidation using chloride as a supporting electrolyte. The effect of operating parameters such as initial pH, supporting electrolyte concentration, phenol concentration, and charge input was studied using Box-Behnken second order composite experimental design. The effect of current density on COD removal was studied separately. TOC removal and AOX formation were studied for selected conditions. It was found that the formation of chlorinated organic compounds was pronounced at the beginning of electrolysis, but it was reduced to lower levels by extended electrolysis.
Journal of Electrochemical Science and Technology
Persistent organic pollutants (POPs) and emerging pollutants (EP) are characterized by their difficulty to be removed through biological oxidation processes (BOPs); they persist in the environment and could have adverse effects on the aquatic ecosystem and human health. The electro-oxidation (EO) process has been successfully used as an alternative technique to oxidize many kinds of the aforementioned pollutants in wastewater. However, the EO process has been criticized for its high energy consumption cost and its potential generation of by-products. In order to decrease these drawbacks, its combination with biological oxidation processes has been reported as a solution to reduce costs and to reach high rates of recalcitrant pollutants removal from wastewaters. Thus, the location of EO in the treatment line is an important decision to make, since this decision affects the formation of by-products and biodegradability enhancement. This paper reviews the advantages and disadvantages of EO as a pre and post-treatment in combination with BOPs. A perspective of the EO scaleup is also presented, where hydrodynamics and the relationship of A/V (area of the electrode/working volume of the electrochemical cell) experiments are examined and discussed.
Water Research, 2009
The electrochemical oxidation of organics in water was investigated theoretically and experimentally to determine the role of several operative parameters on the performances of the process in the presence and in the absence of sodium chloride. Theoretical considerations were used to design the experimental investigation and were confirmed by the results of the electrochemical oxidation of oxalic acid (OA) at boron doped diamond (BDD) or IrO 2-Ta 2 O 5 (DSA-O 2) anodes in a continuous batch recirculation reaction system equipped with a parallel plate undivided electrochemical cell. Polarization curves and chronoamperometric measurements indicated that, in the presence of chlorides, the anodic oxidation of OA is partially replaced by an indirect oxidation process. This result was confirmed by electrolyses experiments that show that, in the presence of suitable amount of chlorides, oxidation of OA takes place mainly by a homogeneous process. Interestingly, a very different influence of the nature of the anodic material, the flow rate and the current density on the performances of the process arises in the absence and in the presence of chlorides so that optimization of the two processes requires very different operative conditions. In the absence of chlorides, high current efficiency (CE) is obtained at BDD when most part of the process is under charge transfer controlled kinetics, i.e. when low current densities and high flow rates are imposed. On the other hand, in the presence of NaCl, higher CE are generally obtained at DSA anode when high current densities and low flow rates are imposed, i.e. when a high concentration of chemical oxidants is obtained as a result of the chloride oxidation. The effect of other operative parameters such as the OA concentration and the pH were further investigated.
Electro-degradation and biological oxidation of non-biodegradable organic contaminants
Chemical Engineering Journal, 2009
The speciality chemical process requires large volumes of water of high purity and generates equally large volumes of wastewater. The generated wastewater is complex and highly variable with respect to its nature, containing high levels of chemical oxygen demand (COD), dissolved and suspended solids, a medium to low level of biochemical oxygen demand, a considerable amount of total organic halogen and an intense colour. In the present study the actual effluent was collected from the organic industry and various experiments were conducted to reduce the pollution load and reuse treated wastewater.