Performance Of Electrocoagulation Process Research Articles

A hybrid electrocoagulation-biocomposite adsorption system for the decolourization of dye wastewater

Among the various methods for the removal of azo dye, electrocoagulation is recognized to be highly efficient. However, the process is associated with high operation and maintenance cost, which demands the need for reducing the electrolysis time without compromising the performance efficiency. This can be achieved by adopting hybrid electrocoagulation process with a low-cost but effective process, such as adsorption. The study investigated the performance of a hybrid electrocoagulation-biocomposite system (H-EC-BC) for removing methyl orange dye. Firstly, the operating parameters of electrocoagulation process were optimized and a removal efficiency of 99% has been attained using Fe-SS electrodes at a pH of 6 for a reaction time of 30 min. The performance of EC process was found to be decreasing with increase in dye concentration. Secondly, biocomposite was synthesized from Psidium guajava leaves and characterized using SEM, FTIR, EDAX, and XRD analyses. The results suggested that it is having a porous nature and cellulose crystal structure and confirmed the presence of chemical elements such as carbon (65.2%), oxygen (29.1%) as primary with Fe, Cl, Na and Ca as secondary elements. The performance of the biocomposite was evaluated for the dye adsorption using spectrophotometric methods. Various operating parameters were optimized using experimental methods and a maximum removal efficiency of 65% was achieved at a pH of 6, dosage of 5 g/L and an adsorption contact time of 120 min. The maximum efficiency (92.78%) was obtained with Fe-SS electrodes and KCl as a sustaining electrolyte under acidic circumstances (pH 6). The biocomposite was observed to be more efficient for higher dye concentration. Langmuir and Freundlich adsorption isotherms were fitted with the experimental results with R2 values as 0.926 and 0.980 respectively. The adsorption kinetics were described using Pseudo-first and Pseudo-second order models, wherein Pseudo-second order model fits the experimental results with R2 value of 0.999. The energy consumption of electrocoagulation (EC) process in the hybrid H-EC-BC system was compared to that of a standard EC process. The results demonstrated that the hybrid system is approximately 7 times more energy efficient than the conventional process, thereby implicating its adaptability for field application.

Performance evaluation and life cycle assessment of electrocoagulation process for manganese removal from wastewater using titanium electrodes

Excess manganese (Mn) concentrations can pose environmental and health risks. Currently, research on Mn removal by electrocoagulation (EC) using transition metal electrodes and the determination of its potential environmental impacts is limited. This study aims to assess the electrocoagulation process's performance with a titanium electrode as a sacrificial anode while also performing a life cycle assessment (LCA) of the process. The initial pH, current density (CD), electrode spacings, electrolyte types, concentrations, and electrode arrangement were all examined. For synthetic wastewater, most of the experiments used a concentration of Mn of 2 mg/L and sodium chloride as a supporting electrolyte at a concentration of 1 g/L. LCA software (OpenLCA 1.11) was used to assess the potential environmental impacts. Optimal operating conditions within the experimental range were as follows: initial pH = 7, CD = 10 mA/cm2, gap distance = 2 cm, and 1 g/L NaCl. Under these conditions, the maximum Mn removal efficiency was 96.5% after 60 min. There was an improvement of 2% rise after 60 min when the temperature increased from 20 °C to 40 °C. For real wastewater, the highest removal efficiencies for Mn and chemical oxygen demand after 60 min were 91.3% and 92%, respectively. The pseudo second order model provides the highest coefficient of determination for expressing the experimental data. Global warming, human non-carcinogenic toxicity, and terrestrial ecotoxicity were the most important categories of impact examined in this work according to the LCA (0.00064 kg CO2 eq, 0.00018 kg 1,4-DCB, and 0.00028 kg 1,4-DCB, respectively). To effectively remove Mn using EC with Ti electrodes, it appears that a period of electrolysis of 10 min would be sufficient under most of the conditions investigated in this study. The reduction in the electrolysis time will lead to a reduction in the operating costs of the system.

The Performance of Electrocoagulation Process in Removing Organic and Nitrogenous Compounds from Landfill Leachate in a Three-Compartment Reactor

The Performance of Electrocoagulation Process in Removing Organic and Nitrogenous Compounds from Landfill Leachate in a Three-Compartment Reactor

Comparison of the effectiveness electrocoagulation of dye (batik waste water) using iron and zinc as an anodes

This study aims to obtain dye (batik waste water) treatment by electrocoagulation with optimal results. The performance of electrocoagulation process was carried out in batch reactor. Four variables were taken which thought to greatly influence the electrocoagulation process, such as: distance between electrodes, voltage, acidity (pH) and electrolysis time. In this process, samples of 20 mL were taken out from the batch at 5, 10, 15, 20, 25, 30, 35, 40, 45 dan 50 minutes of contact time. Results obtained show that the most effective removal efficiency could be achieved at alkaline condition. Research that has been done shows that the percentage of wastewater treatment results is strongly influenced by the four variable changes. The study demonstrated that the lowest degradation efficiency occours at acid pH, while an increase temperature has only a slight effect on the electrocoagulation process. The maximum results from the electrocoagulation processes was obtained, with determine by measurement of chemical oxygen demand (COD). The results showed that, iron is better used as an anode than zinc. The effectiveness electrocoagulation reached optimal at 96.54% (at Fe anode) and 81.65% (at Zn anode), at alkaline condition (pH > 9), electrolysis time of 30 minutes, electrode distance of 1 cm and temperature at 70°C.

Removal of Reactive Dye from Textile Mill Wastewater by Leading Electro-Coagulation Process Using Aluminum as a Sacrificial Anode

This work presents the highest color removal efficiency for Textile wastewater by Electrocoagulation (EC) process using Aluminum as a sacrificial anode which is presently used for the purification of many types of water and wastewater. The effecting parameters such as applied electrical current, electrolysis time and initial pH were studied to achieve higher removals. In this process, sample was taken from real effluent of reactive dyes fabric. The performance of Electrocoagulation process was carried out in batch reactor at regular interval of 20 minutes. Obtained results indicated the most effective color removal efficiency was achieved at 0.75A of applied electrical Current. They were (97.5% - 98.1%), at electrolysis time of 120 minutes, pH10, pH7 respectively and COD removal efficiency was (54 % - 65%) at 0.75A, 0.9A respectively. In this work, the initial pH did not strongly affect the removal efficiencies significantly over a wide range. Therefore, adjustment of initial pH before treatment was not required in this practical application. The power consumption was found to be 6 kWh/m3. To determine COD removal rate dependency to electrical current, a kinetic study was carried out and data were in good covenant with the first order kinetic model.

Removal of a Persistent Dye in Aqueous Solutions by Electrocoagulation Process: Modeling and Optimization Through Response Surface Methodology

This study is related to a laboratory study on the performance of electrocoagulation process using Fe and Al electrodes to treat bio-recalcitrant synthetic dye in a batch mode operation. The performance of the electrolytic cell resulted from its capability of generating in situ coagulants to remove methylene blue from aqueous solution. A factorial experimental design was firstly used to determine the effects of each parameter on methylene blue (MB) removal. The MB concentration, current intensity, electrolysis time, and electrode type were the main influent parameters on the response studied. The respective contributions of the main factors on the percentage of MB removal were 38.37, 18.41, 28.49, and 9.35%. Result analyses show that MB concentration had a negative effect, whereas current intensity and electrolysis time had positive effect on the efficiency. Using a 24 factorial matrix, the best performance for MB (89% of MB removed) was obtained by selecting Fe anode operated at a current intensity of 3.0 A during 40 min of treatment time in the presence of 20 mg/L of MB. A central composite design (CCD) methodology was subsequently used for optimization of EC process in treating MB. Under the optimal conditions determined by this method, EC can economically be applied to remove MB (89% of MB removal for a total cost of 0.32 US$/ m3) while using Fe anode operated at a current intensity of 1.44 A during 34 min of treatment time in the presence of 11.2 mg/L of MB.

Electrocoagulation process performance in removal of TOC, TDS, and turbidity from surface water

Electrocoagulation process performance in removal of TOC, TDS, and turbidity from surface water

Integrated two-phase purification procedure for abatement of pollutants from sanitary landfill leachates

The improvement of pollutant removal, in addition to low toxicity and a high biodegradability index, from sanitary landfill leachate (SLL) effluents treated in a two-process purification system was investigated. As a purification strategy, an electrocoagulation (EC) process followed by a biological purification step was applied. The response surface methodology was used to study the best EC process performance as a function of initial pH, current density and electrolysis time. The maximum removal of turbidity, chemical oxygen demand (COD) and iron concentration were achieved at an initial pH of 5, a current density of 128.57 A m−2 and an electrolysis time of 120 min. Regarding the best EC conditions, toxicity, based on an Artemia salina bioassay, and biodegradability, based on the Zahn-Wellens test, were assessed in raw SLL effluents and after their treatment with EC and biological processes. After stripping almost 98% ammonia of the concentration after EC experiments at 0, 5 and 120 min electrolysis times, the toxicity was also assessed. From the bioassay tests, the best result for the toxicity level was achieved for a 5 min electrolysis time. The Zahn-Wellens test showed that the EC process as a first stage of a two-phase treatment system was sufficient and provided a biodegradability index above 70%. By treating with a biological process, a significant improvement in toxicity was attained. However, most probably, the remaining toxicity could be attributed to ammonia. Thus, a pre-treatment based on the EC process integrated to a biological one can be considered as a promising and challenging alternative.

Electro-coagulation process performance in treatment of the effluent from egg processing industry

Electro-coagulation process performance in treatment of the effluent from egg processing industry

A COMPARISON BETWEEN ALUMINIUM AND IRON ELECTRODES IN ELECTROCOAGULATION PROCESS FOR GLYPHOSATE REMOVAL

This study was intended to compare the performance of electrocoagulation process using aluminium and iron electrodes for glyphosate removal in aqueous solution. The effects of initial glyphosate concentration, electrocoagulation time and distance between electrodes, were discussed in detail. An electrocoagulation tank of 500mL with two metal plates electrodes, same in dimensions and metal types, was set up to perform batch mode laboratory experiment and the glyphosate in white powder was first diluted with deionized water. Production of metal cations showed an ability to neutralize negatively charged particles, which then encouraged to bind together to form aggregates of flocs composed of a combination of glyphosate and metal hydroxide. Compared with iron electrodes, aluminium electrodes were more effective for glyphosate removal, with a removal efficiency of over than 80%. This study revealed that electrocoagulation process using aluminium electrodes is reliable, especially designed for initial concentration 100 mg/L, electrocoagulation time 50 min, and distance between electrodes 6 cm. Finally, it can be concluded that electrocoagulation process using aluminium electrodes is efficient for glyphosate removal from aqueous environments.

Effect of presence of chemical species on removal of phenol in electrocoagulation process

Effect of the presence of chemical species, namely, NaHCO3, CaSO4, MgSO4, and MgCl2, on the performance of electrocoagulation (EC) process when treating synthetic phenolic wastewater was investigated. The investigation was performed using individual and combinations of two, three, and four species. Chemical species, under investigation, were added to phenol solution that was prepared using distilled water. Additionally, effects of operational parameters, namely, initial phenol concentration, current density, and supporting electrolyte (NaCl) concentration on the process performance was also studied using phenol solution that was prepared using tap water. The results showed that presence of chemical species such as bicarbonates and sulfates have negative effects on the performance of EC process. Removal efficiency of phenol was found to decrease with respect to time when CaSO4, MgSO4, and NaHCO3 were added to phenol solution. As an example, when only CaSO4 was added to the solution, more than 30% of phenol remained in solution after 10 min of investigation, while complete removal of phenol was achieved after 2 min when chemical species under investigation were not added. The results also showed that addition of more species resulted in more reduction of phenol removal efficiency. When CaSO4 and MgSO4 were added to the solution, 35% of phenol remained in solution after 10 min of treatment period.

Optimization of the electrocoagulation process for the removal of lead from water using aluminium as electrode material

Lead is a priority substance in the framework of the European water policy (Water Framework Directive 2000/60/EC and Water Environmental Quality Standards Directive 2008/105/EC), since it presents a significant risk to biota and humans, given its persistence, toxicity and bioaccumulation characteristics. This study is devoted to focus on lead removal by means of electro coagulation (EC). The performance of EC process with aluminium electrodes for removal of lead on laboratory electrochemical cell was studied. The effects of various parameters such as electrochemical treatment time, solution pH, current density (J), electrolyte concentration and electrical energy consumption on the percentage of lead removal were investigated. The optimum conditions for EC process were identified as pH 5, current density of 2.67 mA cm−2 and electrolyte concentration of 0.5 g L−1. Effect of EC reactor design parameters such as the surface-area-to-volume ratio and the distance between electrodes were investigated. The obtained experimental results showed that optimal lead removal was achieved with distance between electrodes of 0.5 cm and surface-area-to-volume ratio (S/V) of 11.2 m−1. Under optimal conditions with 30 min treatment, the lead removal efficiency was about 99%. The optimal operating conditions can achieve efficient removal in a relatively short reaction time and low energy consumption. In the light of these results, EC could be regarded as a potential technique for the treatment of industrial wastewater containing lead.

Abatements of reduced sulphur compounds, colour, and organic matter from indigo dyeing effluents by electrocoagulation

In the present study, the treatability of indigo dyeing effluents by the electrocoagulation (EC) process using stainless steel electrodes was experimentally investigated. The samples used were concentrated with main pollutant parameters of chemical oxygen demand (COD) (1000–1100 mg/L), reduced sulphur species (over 2000 mg , and colour (0.12–0.13 1/cm). The study focused on the effect of main operation parameters on the EC process performance in terms of abatement of reduced sulphur compounds as well as decolourization and organic matter reduction. Results indicated that the performance of EC proved to be high providing total oxidation of the reduced sulphur compounds, almost complete decolourization, and COD removal up to 90%. Increasing applied current density from 22.5 to 45 mA/cm2 appreciably improved abatement of the reduced sulphur compounds for Sample I, but a further increase in the applied current density to 67.5 mA/cm2 did not accelerate the conversion rate to sulphate. The process performance was adversely affected by increasing initial concentration of the reduced sulphur compounds. Decolourization and organic matter removal efficiency enhanced with increasing applied current density. The main removal mechanism of the reduced sulphur compounds by EC was explained as conversion to sulphate via oxidation. Conversion rate to sulphate fitted pseudo-first-order kinetics very well.

COD REDUCTION OF BAKER'S YEAST WASTEWATER USING BATCH ELECTROCOAGULATION

The aim of the present work was to investigate experimentally the reduction of Chemical Oxygen Demand (COD) levels from baker’s yeast wastewater (BYW) using batch electrocoagulation (EC) treatment process. An electrocoagulation unit with six iron electrodes was designed to achieve this treatment task. The effect of several operational parameters including pH, direct current (DC) density (Iρ), mixing speed (MS), and temperature (T) on the performance of EC process was studied. The results indicated that the maximum removal efficiency of the COD was up to 85%. The visual test showed that the electrocoagulation process was able to remove completely the dark brown color of baker’s yeast wastewater. The corresponding electrical energy and electrode consumption per kg COD removed was around 0.493 kWh and 2.956 kg iron, respectively. In addition, it was demonstrated that the reduction rate of COD follows the first-order model whose kinetic parameter, k, depends strongly on the DC current density according to a power law relation.

Application of electrochemically dissolved iron in the removal of tannic acid from water

Effects of some experimental parameters (supporting electrolyte, initial pH and current density) on the performance of electrocoagulation process using iron electrodes were investigated. Results of experiments showed that dissolution of iron is purely electrochemical and fits well with Faraday's law and leads to Fe2+ which are chemically oxidized into Fe3+ in aerated conditions. In neutral and alkaline conditions, the reaction between hydroxyl ions generated at the cathode and dissolved iron ions forms insoluble hydroxo-iron species. Potentiodynamic polarization tests showed that the formation of passive film on iron anode limits the continuous electrochemical dissolution of iron. Corrosion and pitting potentials largely depend on the nature of supporting electrolyte. The dissolution of iron is facilitated by pitting corrosion with chloride ions, but it is inhibited in the presence of phosphate ions. However, fluctuations between pitting and passivity were observed in the presence of sulfate ions but this can be eliminated by the addition of small amount of chloride ions. Electrocoagulation using iron electrodes was applied to remove tannic acid (TA) from water. The obtained results have shown that the efficiency of this electrochemical technology depends largely on certain operating parameters including initial pH, current density and nature of supporting electrolyte. Almost complete COD removal can be achieved in batch electrochemical reactor using iron electrodes under optimized operating conditions after consumption of 1Ahdm−3. The elimination of TA from water involves a primary mechanism leading to the formation of stable black organometallic complexes and a second mechanism through sweep coagulation.

Removal of Co (II) from aqueous solution by electrocoagulation process using aluminum electrodes

Electrocoagulation (EC) process is an effective method for the removal of heavy metal ions from water and wastewater effluents. In the present study, the removal of Cobalt ions from aqueous solutions has been studied by EC process with aluminum electrodes. The effect of several parameters such as pH, current density, time, conductivity and initial metal concentration of contaminant on the performance of EC process has been investigated. The results indicated that the initial pH has a significant effect on the removal efficiency. The current density and electrolysis period has a positive effect on the Co 2+ removal efficiency. Also, it was found that the electrical energy consumption decreased with an increase in the solution conductivity. By-products obtained from the EC process were analyzed by using SEM, EDAX and XRD, and the results have been explained.

Treatment of metal plating wastewater by electrocoagulation

AbstractIn this study, the performance of electrocoagulation process in the treatment of metal plating wastewater was investigated using different combinations of aluminum (Al) and iron (Fe) electrodes. The effect of applied current, metal concentration, and treatment time on the metal removal efficiency was investigated. The results show that electrocoagulation can effectively reduce metal ions to a very low level. The Fe‐Fe and Fe‐Al electrode combinations were more effective for the removal of Cu, Cr, and Ni from metal plating wastewater. Almost 100% removal of Cu, Cr, and Ni was achieved with initial Cu concentration of 335 mg/L, Cr concentration of 193 mg/L, Ni concentration of 526 mg/L after 60 min of electrocoagulation at current of 2.0 A with Fe‐Al electrode combination. © 2011 American Institute of Chemical Engineers Environ Prog, 2011.

Removal of Mn 2+ ions from synthetic wastewater by electrocoagulation process

Electrocoagulation (EC) process has been used as an effective method for the removal of a variety of contaminants, especially heavy metal ions, from water and wastewater effluents. In this study, the removal of Mn 2+ ions from solutions has been studied by EC process with aluminium electrodes. The effect of influential parameters such as initial pH, applied current density, electrolysis time, solution conductivity and initial metal concentration on the performance of EC process has been investigated. It was found that the optimum initial pH to remove Mn 2+ ions was 7.0. Also, the results indicated that increasing the current density and electrolysis time has a positive effect on the Mn 2+ removal efficiency. The removal of Mn 2+ ions was not influenced by the solution conductivity but the electrical energy consumption decreased with an increase in the solution conductivity. In addition, the results of our study revealed that Mn 2+ removal rate decreased with increasing the initial concentration of the contaminant. The by-products obtained from the electrocoagulation process were analyzed and explained using SEM, EDAX and XRD.

Complexing agent and heavy metal removals from metal plating effluent by electrocoagulation with stainless steel electrodes

In the present study, the treatability of a metal plating wastewater containing complexed metals originating from the nickel and zinc plating process by electrocoagulation using stainless steel electrodes was experimentally investigated. The study focused on the effect of important operation parameters on electrocoagulation process performance in terms of organic complex former, nickel and zinc removals as well as sludge production and specific energy consumption. The results indicated that increasing the applied current density from 2.25 to 9.0 mA/cm 2 appreciably enhanced TOC removal efficiency from 20% to 66%, but a further increase in the applied current density to 56.25 mA/cm 2 did not accelerate TOC removal rates. Electrolyte concentration did not affect the process performance significantly and the highest TOC reduction (66%) accompanied with complete heavy metal removals were achieved at the original chloride content (≈1500 mg Cl/L) of the wastewater sample. Nickel removal performance was adversely affected by the decrease of initial pH from its original value of 6. Optimum working conditions for electrocoagulation of metal plating effluent were established as follows: an applied current density of 9 mA/cm 2, the effluent's original electrolyte concentration and pH of the composite sample. TOC removal rates obtained for all electrocoagulation runs fitted pseudo-first-order kinetics very well ( R 2 > 92–99).