Application of Taguchi’s experimental design method for optimization of Acid Red 18 removal by electrochemical oxidation process

Background: Electro-oxidation is developed as an electrochemical method to overcome the problems of the conventional decolorization technologies and is an appropriate alternative for the treatment of colored wastewater from various industries. The purpose of this study was to evaluate the efficiency of the electrochemical oxidation process in removal of chemical oxygen demand (COD) and Acid Red 18 (AR18) dye from aqueous solutions. Methods: In this research, a laboratory scale of electro-coagulation reactor for the treatment of synthetic wastewater was made and studied. The effects of different variables including pH, current density, dye concentration, and electrolysis time were investigated. The experiment steps were designed by DesignExpert 10 software using the selected variables. Finally, the dye and COD analysis was performed by spectrophotometer. The optimization was performed using Taguchi fractional factorial design during the removal of dye and COD. Results: Maximum removal of dye (89%) and COD (72.2%) were obtained at pH=3, current density=20 mA/cm2 , initial dye concentration=100 mg/L, and reaction time=45 min. ANOVA test showed a significant relationship between statistical model and test data. Also, the results indicate that the distribution of the residues of the model was normal. Conclusion: By designing experiments through Taguchi method, the removal process will be optimized and by decreasing the number of experiments, the optimal conditions for pollutant removal will be prepared. The results suggest that the Electro-oxidation system is a very suitable technique for the enhancement of wastewater treatment.

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Combined electrocoagulation and electro-oxidation of industrial textile wastewater treatment in a continuous multi-stage reactor

Water Science & Technology ◽

10.2166/wst.2017.415 ◽

2017 ◽

Vol 76 (9) ◽

pp. 2515-2525 ◽

Cited By ~ 6

Author(s):

Edison GilPavas ◽

Paula Arbeláez-Castaño ◽

José Medina ◽

Diego A. Acosta

Keyword(s):

Wastewater Treatment ◽

Current Density ◽

Design Of Experiment ◽

Operating Cost ◽

Oxygen Demand ◽

Textile Wastewater ◽

Fractional Factorial ◽

Multi Stage ◽

Electro Oxidation ◽

Textile Wastewater Treatment

Abstract A combined electrocoagulation (EC) and electrochemical oxidation (EO) industrial textile wastewater treatment potential is evaluated in this work. A fractional factorial design of experiment showed that EC current density, followed by pH, were the most significant factors. Conductivity and number of electrooxidation cells did not affect chemical oxygen demand degradation (DCOD). Aluminum and iron anodes performed similarly as sacrificial anodes. Current density, pH and conductivity were chosen for a Box–Behnken design of experiment to determine optimal conditions to achieve a high DCOD minimizing operating cost (OC). The optimum to achieve a 70% DCOD with an OC of USD 1.47/m3 was: pH of 4, a conductivity of 3.7 mS/cm and a current density of 4.1 mA/cm2. This study also shows the applicability of a combined EC/EO treatment process of a real complex industrial wastewater.

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Electrochemical oxidation as a post treatment for biologically tannery wastewater in batch reactor

Water Science & Technology ◽

10.2166/wst.2019.380 ◽

2019 ◽

Vol 80 (7) ◽

pp. 1326-1337 ◽

Cited By ~ 2

Author(s):

Tran Le Luu ◽

Djeuga Djeuga Franck Stephane ◽

Nguyen Hoang Minh ◽

Nguyen Duc Canh ◽

Bui Xuan Thanh

Keyword(s):

Energy Consumption ◽

Electrochemical Oxidation ◽

Organic Compounds ◽

Current Density ◽

Batch Reactor ◽

Post Treatment ◽

Pollutant Removal ◽

Tannery Wastewater ◽

Stirring Rate ◽

A Current

Abstract Tannery wastewater is known to contain high concentrations of organic compounds, heavy metals, nitrogen, sulphur, chromium, and many other chemicals. Both aerobic and anaerobic biological approaches have proven ineffective in the treatment of tannery wastewater due to the high salinity and toxic chemicals contained within the medium. Electrochemical oxidation presents a promising method for solving this problem. High pollutant removal efficiency, low energy consumption, and high electrode stability are three important factors supporting the feasibility of an efficient electrochemical treatment process. In the present study, electrochemical oxidation was performed as a post treatment for tannery wastewater (after biological pre-treatment) in a batch reactor using Ti/RuO2, Ti/IrO2, and Ti/BDD anodes. The effects of pH, current density, stirring rate and treatment time were studied to assess the treatment efficiency as well as the energy consumption of the process. The results showed that colour, chemical oxygen demand (COD), total organic carbon (TOC), and total nitrogen (TN) removal efficiencies on the electrodes were: Ti/RuO2 (88.8%, 88.40%, 64.0%, 96.4%), Ti/IrO2 (85.40%, 85.9%, 52.3%, 51.4%), Ti/BDD (90.60%, 94.7%, 90.5%, 82.7%) respectively, at a current density of 80 mA/cm2. All three electrodes demonstrated optimal performance at a pH of 8, a stirring rate of 400 rpm, a current density of 80 mA/cm2, and an electrolysis time of 5 h. The concentration of tri-chloromethane by-product was detected with limiting value. Electrochemical oxidation thus offers a feasible method for removing organic compounds and nutrients from tannery wastewater.

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Comparing the Effects of Types of Electrode on the Removal of Multiple Pharmaceuticals from Water by Electrochemical Methods

Water ◽

10.3390/w12092332 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2332

Author(s):

Yu-Jung Liu ◽

Yung-Ling Huang ◽

Shang-Lien Lo ◽

Ching-Yao Hu

Keyword(s):

Electrode System ◽

Electrochemical Methods ◽

Synthetic Wastewater ◽

Coagulation System ◽

Transformation Rate ◽

Lack Of Information ◽

Pharmaceutical Removal ◽

Β Blocker ◽

Electro Oxidation ◽

Electro Coagulation

Considering the lack of information on simultaneously removing multiple pharmaceuticals from water or wastewater by electrochemical methods, this study aimed to investigate the removal of multiple pharmaceuticals by electro-coagulation and electro-oxidation based on two types of electrodes (aluminum and graphite). The synthetic wastewater contained a nonsteroidal anti-inflammatory drug (diclofenac), a sulfonamide antibiotic (sulfamethoxazole) and a β-blocker (atenolol). The pharmaceutical removal with electro-oxidation was much higher than those with the electro-coagulation process, which was obtained from a five-cell graphite electrode system, while the removal of pharmaceuticals with aluminum electrodes was about 20% (20 µM). In the electro-coagulation system, pharmaceutical removal was mainly influenced by the solubility or hydrophilicity of the compound. In the electro-oxidation system, the removal mechanism was influenced by the dissociation status of the compounds, which are attracted to the anode due to electrostatic forces and have a higher mass transformation rate with the electro-oxidation process. Therefore, atenolol, which was undissociated, cannot adequately be eliminated by electro-oxidation, unless the electrode’s surface is large enough to increase the mass diffusion rate.

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The removal of the trivalent chromium from the leather tannery wastewater: the optimisation of the electro-coagulation process parameters

Water Science & Technology ◽

10.2166/wst.2011.232 ◽

2011 ◽

Vol 63 (3) ◽

pp. 385-394 ◽

Cited By ~ 8

Author(s):

E. GilPavas ◽

I. Dobrosz-Gómez ◽

M. Á. Gómez-García

Keyword(s):

Current Density ◽

Oxygen Demand ◽

Trivalent Chromium ◽

Biological Oxygen Demand ◽

Optimal Conditions ◽

Electrode Gap ◽

Surface Method ◽

Response Capacity ◽

Electro Coagulation ◽

Parameter Values

The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28°C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values.

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Experimental Study on Papermaking Wastewater by Advanced Electrochemical Oxidation Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.726-731.1699 ◽

2013 ◽

Vol 726-731 ◽

pp. 1699-1703

Author(s):

Lin Lin Huang ◽

Jun Feng Liu ◽

Bin Sun ◽

Nan Zhang ◽

Yong Qing Tang ◽

...

Keyword(s):

Electrochemical Oxidation ◽

Current Density ◽

Treatment Time ◽

Oxygen Demand ◽

Treatment Method ◽

Electrochemical Reactor ◽

Advanced Treatment ◽

Processing Unit ◽

Optimum Reaction ◽

Papermaking Wastewater

Papermaking wastewater effluent from a biological processing unit was treated by an advanced treatment method-electrochemical oxidation process. The experiments were carried out in an electrochemical reactor using RuO2\SnO2 coated on titanium as anode and stainless steel as cathode. The changes of Chemical Oxygen Demand (COD) reduction and other relative parameters have been determined as a function of treatment time and applied current density. The optimum reaction time and current density was 60min and 5mA/cm2, respectively. Results indicate that as an advanced treatment method, electrochemical oxidation can treat papermaking wastewater to achieve the standard of effluents effectively.

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Removal of Refractory Organic Compounds from Wastewater by Various Advanced Oxidation Process - A Review

Current Environmental Engineering ◽

10.2174/2212717806666181212125216 ◽

2019 ◽

Vol 6 (1) ◽

pp. 8-16 ◽

Cited By ~ 5

Author(s):

Manjari Srivastav ◽

Meenal Gupta ◽

Sushil K. Agrahari ◽

Pawan Detwal

Keyword(s):

Organic Compounds ◽

Conventional Treatment ◽

Advanced Oxidation Process ◽

Oxidation Process ◽

Oxygen Demand ◽

Ultra Violet ◽

Advanced Oxidation ◽

Complete Removal ◽

Pollutant Removal ◽

Treatment Technologies

Per capita average annual freshwater availability is gradually reduced due to increasing population, urbanization and affluent lifestyles. Hence, management of wastewater is of great concern. The wastewater from different industries can be treated by various conventional treatment methods but these conventional treatment technologies seem to be ineffective for the complete removal of pollutants especially refractory organic compounds that are not readily biodegradable in nature. Detergents, detergent additives, sequestering agents like EDTA, Pesticides, Polycyclic aromatic hydrocarbons, etc. are some of the recalcitrant organic compounds found in the wastewater. One of the treatment technologies for the removal of recalcitrant organic compounds is Advanced Oxidation Process (AOP). The production of hydroxyl free radical is the main mechanism for the AOP. AOP is a promising technology for the treatment of refractory organic compounds due to its low oxidation selectivity and high reactivity of the radical. Hydrogen peroxide (H2O2), Ozonation, Ultra-violet (UV) radiation, H2O2/UV process and Fenton’s reaction are extensively used for the removal of refractory organic compounds thus reducing Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), phenolic compounds, dyes etc. to great extent. From the studies, we found that Fenton’s reagents appear to be most economically practical AOP systems for almost all industries with respect to high pollutant removal efficiency and it is also economical. From the energy point of view, the ozone based process proves to be more efficient but it is costlier than the Fenton’s process.

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Degradation of cyanide, aniline and phenol in pre-treated coke oven wastewater by peroxide assisted electro-oxidation process

Water Science & Technology ◽

10.2166/wst.2018.503 ◽

2018 ◽

Vol 78 (10) ◽

pp. 2214-2227 ◽

Cited By ~ 9

Author(s):

Hariraj Singh ◽

Brijesh Kumar Mishra

Keyword(s):

Hydrogen Peroxide ◽

Current Density ◽

Advanced Oxidation Process ◽

Oxidation Process ◽

Removal Rate ◽

Operating Cost ◽

Coke Oven ◽

Graphite Electrodes ◽

Electro Oxidation ◽

Pre Treatment

Abstract The present study explored the feasibility of using graphite electrodes for the electrochemical oxidation of cyanide, thiocyanate, phenol and aniline with hydrogen peroxide. The dosing effects of hydrogen peroxide and current density were examined in the pre-treated coke oven wastewater. It was found that 0.025 M hydrogen peroxide and 13.63 mA/cm2 of current density were more favorable for the removal of 100%, 90%, 71% and 40% cyanide, thiocyanate, phenol and aniline respectively. The increased removal of phenol in the coke oven wastewater was attributed to the pre-treatment of wastewater. Initially, 28% phenol was converted to phenolate ion by air stripping process, which increased the removal rate of phenol by the electro-oxidation process as the removal of phenolate is quite easy compared to phenol. The advanced oxidation process degrades the more toxic cyanide into less toxic intermediate cyanate ions (CNO─), which further cut down into nontoxic end products such as N2, HCO3 and CO2. The experimental results show that the primary mechanisms in the oxidation of cyanide and phenol are mediated electro-oxidation by hydroxyl radicals and hypochlorite ions. The operating cost under the optimized conditions for the removal of 100% cyanide and 71% phenol was estimated to be 616.95 INR/m3.

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Electrocoagulation efficiency of the tannery effluent treatment using aluminium electrodes

Water Science & Technology ◽

10.2166/wst.2009.518 ◽

2009 ◽

Vol 60 (8) ◽

pp. 2173-2185 ◽

Cited By ~ 16

Author(s):

Fernando R. Espinoza-Quiñones ◽

Marilda M. T. Fornari ◽

Aparecido N. Módenes ◽

Soraya M. Palácio ◽

Daniela E. G. Trigueros ◽

...

Keyword(s):

Experimental Design ◽

Oxygen Demand ◽

Industrial Process ◽

Fractional Factorial ◽

Effluent Treatment ◽

Process Efficiency ◽

Tannery Effluent ◽

State Variables ◽

Inorganic Pollutants ◽

Electro Coagulation

An electro-coagulation laboratory scale system using aluminium plates electrodes was studied for the removal of organic and inorganic pollutants as a by-product from leather finishing industrial process. A fractional factorial 23 experimental design was applied in order to obtain optimal values of the system state variables. The electro-coagulation (EC) process efficiency was based on the chemical oxygen demand (COD), turbidity, total suspended solid, total fixed solid, total volatile solid, and chemical element concentration values. Analysis of variance (ANOVA) for final pH, total fixed solid (TFS), turbidity and Ca concentration have confirmed the predicted models by the experimental design within a 95% confidence level. The reactor working conditions close to real effluent pH (7.6) and electrolysis time in the range 30–45 min were enough to achieve the cost effective reduction factors of organic and inorganic pollutants' concentrations. An appreciable improvement in COD removal efficiency was obtained for electro-coagulation treatment. Finally, the technical-economical analysis results have clearly shown that the electro-coagulation method is very promising for industrial application.

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Destruction of refractory humic acid by electromechanical oxidation process

Water Science & Technology ◽

10.2166/wst.2000.0384 ◽

2000 ◽

Vol 42 (3-4) ◽

pp. 225-232 ◽

Cited By ~ 10

Author(s):

L.-C. Chaing ◽

J.-E. Chang ◽

T.-Cn. Wen

Keyword(s):

Humic Acid ◽

Electrochemical Oxidation ◽

Humic Substance ◽

Current Density ◽

High Efficiency ◽

Oxidation Process ◽

Chloride Concentration ◽

Chloride Ion ◽

Gel Permeation Chromatography ◽

Indirect Oxidation

Electrochemical oxidation of humic acid has been conducted to evaluate the efficacy of the process for the destruction of high-molecular-weight (HMW) compounds. Experimental results show that the destruction of humic acid obtained by the electrolysis supported by chloride ion is much better than that obtained by sulfate ion. Accordingly, HMW compound such as humic substance is suggested to be resistant to directly anodic oxidation, but to be readily destroyed by an indirect oxidation of chlorine/hypochlorite during an electrochemical treatment process. The effects of operating parameters, including anode material, current density, electrolyte concentration, have been investigated in this study. A tertiary-oxide of Sn, Pd, Ru coated titanium (SPR) anode with high electrocatalytic activity was found to have high efficiency for humic acid destruction, and the destruction efficacy of humic substance increased with increasing current density and chloride concentration. In this study, gel permeation chromatography (GPC) and adsorptive organic halide (AOX) had been performed to examine the variation of organic characteristics during the electrochemical oxidation of humic acid. The results from GPC and AOX show that HMW organic compounds could be effectively destroyed by electrochemical oxidation process, and the process also produced less undesirable chlorinated byproducts than the chlorination process. From the above results, the electrochemical oxidation conducted by indirect oxidation effect of chlorine/hypochlorite could be concluded to be a feasible method for the destruction of HMW compounds.

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Coupled photochemical-biological system to treat biorecalcitrant wastewater

Water Science & Technology ◽

10.2166/wst.2007.385 ◽

2007 ◽

Vol 55 (12) ◽

pp. 95-100 ◽

Cited By ~ 3

Author(s):

J. Bacardit ◽

V. García-Molina ◽

B. Bayarri ◽

J. Giménez ◽

E. Chamarro ◽

...

Keyword(s):

Advanced Oxidation Process ◽

Oxidation Process ◽

Oxygen Demand ◽

Coupled System ◽

Synthetic Wastewater ◽

Second Step ◽

Photochemical Process ◽

Whole Process ◽

Toc Removal ◽

Start Up

The aim of the present work is to study a coupled system to treat biorecalcitrant wastewaters. The combination consists of an advanced oxidation process (AOP) named photo-Fenton (Ph-F), which is a photochemical treatment and a sequencing batch biofilter reactor (SBBR). The synthetic wastewater used to optimise this process is a solution of 200 ppm of 4-chlorophenol (4-CP). The first part of the work is the study of the biodegradability enhancement achieved by the photochemical process, measured as the ratio between the biochemical oxygen demand (BOD5) and the chemical oxygen demand (COD). The second step is the start-up and optimisation of the biological process. The results showed that it is necessary to severely treat the toxic solution (with 500 ppm of [H2O2]0) in order to achieve more than 90% of TOC removal in the whole process. The photochemical and biological treatments lasted 50 minutes and 24 hours, respectively.

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