Destruction of refractory humic acid by electromechanical oxidation process

2000 ◽  
Vol 42 (3-4) ◽  
pp. 225-232 ◽  
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.

Electrochemical oxidation pretreatment of refractory organic pollutants

1997 ◽  
Vol 36 (2-3) ◽  
pp. 123-130 ◽  
Author(s):  
Li-Choung Chiang ◽  
Juu-En Chang ◽  
Shu-Chuan Tseng
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Gel Permeation Chromatography ◽  
Organic Halogen ◽  
Removal Efficiencies ◽  
Refractory Organic Pollutants ◽  
Microtox Test

Refractory pollutants, including lignin, tannic acid, chlortetracycline, and EDTA, were destroyed by an electrochemical oxidation method to evaluate the applicability of this method for industrial wastewater pretreatment. Operation parameters, such as supporting electrolyte, current density, and electrolyte concentration, have been investigated for their influences on COD removal efficiencies during electrolysis. In addition, gel permeation chromatography (GPC), Microtox test, and total organic halogen (TOX) analyses were performed to monitor the changes of organic characteristics of these refractory pollutants. Experimental results show that, among sulfate, nitrate, and chloride, chloride was the best supporting electrolyte, and during electrolysis, both COD and color removal efficiencies were improved by increasing current density and chloride concentration. From GPC analysis results, the electrochemical oxidation process readily destroys high-molecular-weight (HMW) organics. Microtox test results also show that the process can reduce the toxicity of these refractory organic compounds. In addition, TOX concentrations were found to increase at the beginning but then decline during the electrolysis. The above results suggest that the electrochemical oxidation process, which has good efficacy for detoxification and destruction of refractory pollutants, is a promising method for wastewater pretreatment.

Treatment of Wastewater Containing High Concentration Ammonia-Nitrogen by Electrochemical Oxidation Process

2011 ◽  
Vol 393-395 ◽  
pp. 1587-1590
Author(s):  
Ya Feng Li ◽  
Yuan Han Duan
Keyword(s):  
Total Nitrogen ◽  
Current Density ◽  
Oxidation Process ◽  
Chloride Ion ◽  
Chemical Oxidation ◽  
Ammonia Nitrogen ◽  
Ion Concentration ◽  
High Concentration ◽  
Initial Ph ◽  
Plate Distance

The simulant wastewater containing high concentration ammonia-nitrogen was treated by electro-chemical oxidation process in intermittent experiment. The influences of different factors including plate distance,current density, chloride ion concentration and initial pH on ammonia-nitrogen and total nitrogen removal were studied.According to the results of the test, the optimal reaction condition was determined as follows: plate distance was 40mm，current density was 90mA/cm2，chloride ion concentration was 8000mg/L, initial pH was 10。Under the above condition,the total nitrogen concentration reduced from 2000 mg/Lto 280mg/L when the reaction time was 8h, and the removal rate reached 86%. As we can see, the effect of the treatment is quite positive.

A Dual Cathode Electro Fe2+/S2O82- System Used for Pickle Sauerkraut Wastewater Degradation

2014 ◽  
Vol 1073-1076 ◽  
pp. 924-928
Author(s):  
Shu Yun Shi ◽  
Hong Hui Teng
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Treatment Effect ◽  
Oxidation Process ◽  
Removal Rate ◽  
Cod Removal ◽  
Test Results ◽  
Effect Test ◽  
Plate Distance ◽  
Electrode Plate

Using novel dual cathode/electro/Fe2+/S2O82-system to treat pickle sauerkraut wastewater, the paper investigates the influencing factors (S2O82-dosage, Fe2 +dosage, current density, Wastewater pH, electrode plate distance) of the organic matters removal and the treatment effect. Test results show that the degree of various factors influence on COD removal of sauerkraut wastewater is different. The COD removal is little effected by pH, while largely effected by current density, dosage of Fe2 +and S2O82-dosage. Under the optimum experiment conditions, current density for 30mA/cm-2, dosage of Fe2 +for 8mmol/L, S2O82-dosage for 12 mmol/L, electrode plate distance for 2 cm and pH=6, sixty minutes electrolysis, wastewater removal rate reach up to 92.6%. These results suggest that this electrochemical oxidation process by dual cathode/electro-Fe2+-S2O82-system might provide an alternative for the degradation of pickle sauerkraut wastewater.

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

2018 ◽  
Vol 5 (4) ◽  
pp. 241-248 ◽  
Author(s):  
Zabihollah Yousefi ◽  
Ali Zafarzadeh ◽  
Abdolaziz Ghezel
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Design Method ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Fractional Factorial ◽  
Synthetic Wastewater ◽  
Electro Oxidation ◽  
Electro Coagulation

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.

Current Efficiency and Energy Consumption of Electrochemical Oxidation for Ammonia Removal from Coking Wastewater Using Boron-Doped Diamond Electrodes

2013 ◽  
Vol 295-298 ◽  
pp. 1327-1332 ◽  
Author(s):  
Chun Rong Wang ◽  
Sha Chang ◽  
Min Ye ◽  
Qin Yi Ren
Keyword(s):  
Energy Consumption ◽  
Current Efficiency ◽  
Current Density ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Ammonia Removal ◽  
Ion Concentration ◽  
Coking Wastewater ◽  
Concentration Increase ◽  
Density Decrease

The electrochemical treatment of ammonia using born-doped diamond (BDD) as advanced treatment of coking wastewater was investigated. The effects of chloride ion concentration and current density on current efficiency and energy consumption were also analyzed. The results show that the current efficiency increases with chloride ion concentration increase and current density decrease. And 30% of current efficiency is obtained when current density is less than 19.7mA cm-2, and it decreases above 19.7mA cm-2. The energy consumption decreases with the chloride ion concentration increase and current density decrease. And energy consumption of 0.50kWh g-1 and ammonia removal rate of 84.7% can be achieved at initial ammonia concentration of 100mg L-1, chloride concentration of 900mg L-1 and current density of 29.6mA cm-2.Therefore, BDD electrodes have high current efficiency and low energy consumption, which attributed to its high oxygen evolution overvoltage (2.6V vs. SCE) and low chloride evolution overvoltage (1.5V vs. SCE).

In situ surface reconstruction synthesis of a nickel oxide/nickel heterostructural film for efficient hydrogen evolution reaction

2020 ◽  
Vol 56 (72) ◽  
pp. 10529-10532
Author(s):  
Haixin Chen ◽  
Dongqi Ge ◽  
Junwei Chen ◽  
Ruchun Li ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Electrochemical Oxidation ◽  
Hydrogen Evolution ◽  
Surface Reconstruction ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Oxidation Process ◽  
Large Current ◽  
Large Current Density

In situ reconstruction of NiO/Ni@CC has been successfully achieved through an electrochemical oxidation process, which exhibits a significantly improved HER performance and good stability even at a large current density.

scholarly journals The influence of chloride ion concentration on the localized corrosion of E717 Mg alloy

CORROSION ◽  
10.5006/3601 ◽  
2020 ◽  
Author(s):  
Christos Kousis ◽  
Neil McMurray ◽  
Patrick Keil ◽  
Geraint Williams
Keyword(s):  
Current Density ◽  
Chloride Concentration ◽  
Leading Edge ◽  
Chloride Ion ◽  
Cathodic Current Density ◽  
Ion Concentration ◽  
Localized Corrosion ◽  
Anodic Current Density ◽  
Cathodic Current ◽  
Density Values

The localized corrosion behavior of E717 magnesium alloy immersed in chloride-containing electrolyte is investigated using an in-situ scanning vibrating electrode technique (SVET), coupled with time-lapse imaging (TLI). It is shown that initiation of localized corrosion in chloride-containing electrolyte is characterized by the appearance of discrete local anodes, corresponding with the leading edges of dark, filiform like features, which combine with time to produce a mobile anodic front. The size and growth rate of these features are highly dependent on the chloride ion concentration of the electrolyte. SVET-derived current density maps reveal that the corroded surface left behind the anodic front is cathodically activated, where cathodic current density values progressively decline with increasing distance away from the anodic leading edge. The intensity of localized anodes is highly dependent on the chloride ion concentration, where progressively higher local anodic current density values are observed with increasing chloride ion concentration along with progressively higher rates of volumetrically-determined hydrogen evolution. Breakdown potential, measured using time-dependent free corrosion potential transients and potentiodynamic polarization at neutral and elevated pH respectively, is shown to vary with the logarithm of chloride ion concentration and the time for localized corrosion initiation is progressively increased with decreasing chloride concentration. From the combination of results which are presented herein, the underlying reasons for the influence of chloride ion concentration on the localized corrosion characteristics of E717 alloy will be discussed.

Use of electrochemical oxidation process as post-treatment for the effluents of a UASB reactor treating cellulose pulp mill wastewater

2006 ◽  
Vol 54 (2) ◽  
pp. 207-213 ◽  
Author(s):  
A.P. Buzzini ◽  
D.W. Miwa ◽  
A.J. Motheo ◽  
E.C. Pires
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Pulp Mill ◽  
Electrochemical Treatment ◽  
Post Treatment ◽  
Uasb Reactor ◽  
Recirculation Flow ◽  
Cellulose Pulp ◽  
Uasb Reactors

The main purpose of this study was to evaluate the performance of the electrochemical oxidation process as a post-treatment for the effluents of a bench-scale UASB reactor treating simulated wastewater from an unbleached pulp plant. The oxidation process was performed using a single compartment cell with two plates as electrodes. The anode was made of Ti/Ru0.3Ti0.7O2 and the cathode of stainless steel. The following variables were evaluated: current density (75, 150 and 225 mA cm−2) and recirculation flow rate in the electrochemical cell (0.22, 0.45 and 0.90 L h−1). The increase in current density from 75 to 225 mA cm−2 did not increased the color removal efficiency for the tested flow rates, 0.22, 0.45 and 0.90 L h−1, however the energy consumption increased significantly. The results indicated the technical feasibility of the electrochemical treatment as post-treatment for UASB reactors treating wastewaters from pulp and paper plants.

Treatment of Tannery Wastewater by Electrochemical Oxidation Process

2013 ◽  
Vol 361-363 ◽  
pp. 697-700
Author(s):  
Lin Lin Huang ◽  
Jun Feng Liu ◽  
Nan Zhang ◽  
Bin Sun ◽  
Yu Jie Feng
Keyword(s):  
Electrochemical Oxidation ◽  
Oxidation Process ◽  
Treatment Time ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Electrochemical Reactor ◽  
Tannery Wastewater ◽  
Processing Unit ◽  
Applied Current ◽  
Toc Removal

Electrochemical oxidation process was adopted to treat the tannery wastewater effluent from a biological processing unit. The experiments were carried out in an electrochemical reactor using RuO2\SnO2coated on titanium as anode and stainless steel as cathode. The changes of Chemical Oxygen Demand (COD) reduction, Total Organic Carbon (TOC) removal and other relative parameters have been determined as a function of treatment time, applied current density and chloride concentration. Results indicate that electrochemical oxidation can treat tannery wastewater effectively. The results obtained at 7.5mA/cm2demonstrated that 48.7% of TOC and 58.9% of COD were degraded in 150min of processing. In addition, the addition of chloride showed no significant to the removal of COD and TOC.

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