Electrocoagulation Efficiency Research Articles

Improving Acid Mine Drainage Treatment through Electrocoagulation: Effect of Time, Electrode Distance, and Electrode Types

This study explores the feasibility of employing electrocoagulation technology to manage Acid Mine Drainage (AMD) wastewater, focusing on reducing heavy metal concentrations, particularly iron (Fe) and manganese (Mn). Samples of AMD liquid waste from PT Lhoong Setia Mining in Aceh Province, Indonesia, underwent electrocoagulation using Al-Zn and Al-Fe electrodes with Direct Current (DC). The investigation considered various parameters, including contact time (ranging from 0 to 45 minutes), electrode distance (2, 2.5, and 3 cm), and electrode type (Al-Fe and Al-Zn). The study revealed that prolonged electrocoagulation increased the reduction of Fe and Mn metals due to enhanced Al(OH)3 formation. While Al-Zn electrodes exhibited rapid coagulant formation initially, Al-Fe electrodes sustained effectiveness throughout the process. Optimal reduction of Fe and Mn concentrations occurred at different electrode distances, emphasizing the critical role of spacing in electrocoagulation efficiency. Furthermore, the electrocoagulation process successfully elevated pH levels within acceptable limits and effectively reduced Total Suspended Solids (TSS) in AMD waste, aligning with regulatory standards. This research underscores the potential for electrocoagulation as a viable technology for mitigating the environmental impact of AMD and addresses knowledge gaps related to efficient pollutant removal in mining wastewater treatment. Future studies should explore parameter optimization and consider transitioning to continuous operation for increased effectiveness, particularly in remote mining locations.

Organic and inorganic pollutants removal from tannery effluent using electrocoagulation technique

Abstract Electrocoagulation is an efficient treatment for the concurrent elimination organic and inorganic contaminants from tannery wastewater. The batch electrocoagulation investigations were carried out using mild steel and aluminium as sacrificial anodes and stainless steel as the cathode. Various operating constraints, such as the electrolyte pH, realistic current density, electrolysis time, effluent concentration and supporting electrolyte concentration were appraised to study their effects on electro-coagulation efficiency. The maximum Total Organic Carbon (TOC) removal has been observed was 90 % and 77 % under optimum operating conditions, and the maximum chromium removal has been recorded was 99 % and 90 % using mild steel and aluminium anodes respectively. The experimental data was also fitted with the first order kinetic model. The experimental data were investigated with the Langmuir and Freundlich adsorption isotherm models. The result shows that the experimental data fitted with the Langmuir isotherm model, with a rate of confidence of 0.98, using mild steel as an anode. The solid sludge and the liquid samples were characterized using the SEM (scanning electron microscopy) EDX (energy dispersive X-ray spectrometry), FT-IR (Fourier transform infrared spectrometer) and UV–Visible (Ultraviolet–visible spectroscopy) analyses. All experimental results show that mild steel was an efficient anode, for the instantaneous elimination of organic and inorganic contaminants from tannery wastewater.

Feasibility of improving dust removal efficiency of fly ash fine particles for coal‐fired power plants

AbstractAs solid waste of coal‐fired power plants, atmospheric environmental pollution is caused by fly ash during transportation. The purpose of this study was to improve the dust removal efficiency of fly ash fine particles by electrocoagulation and obtain reasonable operating parameters. The effects of particle concentration, gas velocity, AC frequency, and voltage on particle electrocoagulation efficiency were studied through the establishment of a discrete element soft sphere calculation model, and reasonable electrocoagulation operation parameters were obtained. The dust removal process was evaluated according to the particle number concentration, electrocoagulation efficiency, and particles microscopic characteristics due to the dust removal experiments of fly ash by electrocoagulation. The results demonstrated that increasing particle concentration, reducing gas velocity, and selecting reasonable AC frequency and voltage were effective to improve the real‐time electrocoagulation efficiency and its stability. Under the suitable conditions: voltage of 3 kV, airflow velocity of 5 m s–1, particle concentration of 30 mg m–3 and AC frequency of 100 Hz, the electrocoagulation efficiency was higher than 40%. The electrocoagulation was effective to improve the dust removal efficiency of fly ash fine particles with a relative humidity of air below 70% and ambient temperatures above 20°C.

Removal of Aniline Blue from Textile Wastewater using Electrocoagulation with the Application of the Response Surface Approach

This paper investigated the treatment of textile wastewater polluted with aniline blue (AB) by electrocoagulation process using stainless steel mesh electrodes with a horizontal arrangement. The experimental design involved the application of the response surface methodology (RSM) to find the mathematical model, by adjusting the current density (4-20 mA/cm2), distance between electrodes (0.5-3 cm), salt concentration (50-600 mg/l), initial dye concentration (50-250 mg/l), pH value (2-12 ) and experimental time (5-20 min). The results showed that time is the most important parameter affecting the performance of the electrocoagulation system. Maximum removal efficiency (96 %) was obtained at a current density of 20 mA/cm2, distance between electrodes of 1.75 cm, salt concentration of 462.5 mg/l, dye concentration of 50 ppm, pH value of 7, and time duration of 15 min. On the other hand, the electrocoagulation efficiency was directly proportional to current density, salt concentration, and contact time, while it was inversely proportional to dye concentration. Isotherm experiments showed that the equilibrium data are best fitted to Freundlich isotherm and sips isotherm; whereas the kinetics results showed that the rate of adsorption followed the pseudo-second-order with an R2 value of 98 %.

Performance of batch electrocoagulation with vibration-induced electrode plates for landfill leachate treatment

In electrocoagulation, the accumulation of gas bubbles surrounding the electrode plate surface results in high internal resistance between the electrode plates that obstruct optimum ionic transfer, subsequently reducing the electrocoagulation efficiency. This study investigated the performance of batch electrocoagulation designed with vibration-induced electrode plates in the treatment of landfill leachate to remove colour and chemical oxygen demand (COD). The electrode plates in the electrocoagulation cell were each attached with a DC motor vibrator, varied at different vibration intensity in which its effect on the initial pH, operating time and electrical current of the electrocoagulation were determined. The results showed that the application of vibration-induced electrode plates had a synergistic effect with the electrocoagulation with more than 90 % of colour and COD up to 35 % removed during the treatment at vibration intensity of 2.8 V, initial pH 5, operating time of 35 min, applied current of 2.5A (applied voltage ranged between 11.0–12.9 V), with calculated electrical energy consumption of 8.58 kW h/m3. Overall, the vibration-induced electrode plates were found to enhance the treatment performance due to a combination of improved ionic transfer, enhanced bubbles detachment from the electrode surface and dispersion in the solution. The detachment of bubbles from the plates also enable improved mixing in the solution, leading to an increase in homogeneity and better sludge separation following treatment. In conclusion, this study showed that electrocoagulation with vibration-induced electrode plates provided an improved technique in enhancing the ionic transfer and bubbles dispersion in electrocoagulation for the removal of pollutants.

A perforated electrode design for passivation reduction during the electrochemical treatment of produced water

Produced water refers to the water that is generated when oil and gas are extracted from the ground, and it usually includes the natural water layer within the reservoir (formation water) as well as the injected water. The generation of these large amounts of produced water represents a major environmental and economic challenge to the Oil and Gas Industry. Although many studies have attempted addressing this challenge, there has not been any significant development in the treatment of produced water, and most of these studies have achieved limited success. This work introduces a novel electrocoagulation cell for the treatment of produced water, with the aim of reducing electrode passivation, which has always been considered as a bottleneck in the electrochemical treatment of contaminated water. The main goal of the study is to develop an effective perforated electrode design that can reduce cathode passivation and consequently reduce energy consumption. The novel cell design has been tested and optimized for the treatment of produced water to reduce the concentration of the major organic contaminants in the water. The contaminants reduction efficiency of the proposed design was evaluated and benchmarked with multiple cell configurations. The perforated electrode was superior to other configurations and effective in mitigating passivation, reducing the energy consumption by about 70 % compared to the typical plate electrode. The cell performance was optimized, using response surface methodology, and then operated continuously to evaluate the electrocoagulation efficiency. The new cell design achieved a steadystate reduction of the organic contaminants in the produced water by up to 97 %, 98 % and 95 % for TOC, TPH and O&G, respectively.

Influence of Various Electrode Materials in Electrocoagulation Efficiency: Application in Treatment of Sugar Industry Effluent

Sugar industries generate highly polluted effluent in terms of organics and inorganics load and it is very difficult to treat. In the present study, attempts have been made to use electrocoagulation process to treat the effluent. The treatment was carried out using different electrode materials in different combinations. The influence of pH, current density (CD) and treatment time (tR) on COD removal of sugar industry effluent (SIE) was evaluated. Apart from this, electrode loss, species energy consumption and cost analysis were also carried out. For all electrode materials, pH 7 was found to be optimum, and CD in range of 69.44–104.165 A/m2 provided good treatment of the effluent. The performance of Al–MS electrode combination was seen to be the best, as it reduced initial COD of SIE = 4800 mg/dm3 to 920 mg/dm3 (80.83% COD reduction) in 100 min, with treatment cost INR 326 (USD 4.90)/m3 SIE. Kinetics studies showed COD reduction rate to 1.5 order with respect to COD and 0.57 order with respect to CD. The reaction rate constant lies in between 5.0 and 7.1 $$ \left( {\frac{{{\text{dm}}^{3} }}{\text{mg}}} \right)^{0.5 } \left( {\frac{{{\text{m}}^{2} }}{\text{A}}} \right)^{0.57} \,\min^{ - 1} $$.

Electrocoagulation treatment of swine slaughterhouse wastewater: effect of electrode material

A slaughterhouse is one of the main sources of wastes in meat establishments where animals are killed for consumption as food products. Slaughtering animal processing industries generate a large volume of wastewaters containing very high concentrations of organic matter. In this study, the effect of various electrode materials on the electrocoagulation efficiency was investigated for the treatment of swine slaughterhouse wastewater. These electrodes include pure aluminum (Al), pure iron (Fe) and combination of aluminum – iron (Al – Fe). The performance of these electrodes was investigated in terms of electrocoagulation time, COD removal, electrode consumption, and current density. Additional parameters were also checked before and after treatment such as conductivity, turbidity, BOD, oil and grease, TSS and settleable solids. All electrodes gave more than 90% COD removal however, the pure aluminum electrode is the most efficient (97% removal). It also gave the least electrode consumption. Furthermore, the most efficient current density and time were found to be 25mA/cm2 and 100 minutes respectively. Overall the electrocoagulation treatment of swine slaughterhouse wastewater was successful in terms of reduction of all the parameters considered.

Removal of lead by solar-photovoltaic electrocoagulation using novel perforated zinc electrode

Electrocoagulation can successfully remove metals from diluted wastewater streams with conventional anode materials, such as aluminium, iron and copper. The disadvantages of conventional electrocoagulation systems (i) are expensive because they require substantial electric energy input, and (ii) electrode materials directly influence electrocoagulation efficiency. Developing an electrocoagulation system with a solar photovoltaic energy source is possible. Using this energy source significantly reduces process costs and exhibit high treatment efficiency when combined with a suitable electrode material. In this study, perforated zinc was tested as a novel anode to remove lead ions from aqueous solutions through electrocoagulation treatment powered by solar photovoltaic. The effects of electrode materials, electrode geometry, energy consumption and sludge production on Pb(II) removal were also investigated. Results demonstrated the superior performance of the perforated zinc electrode with a lead ions removal efficiency of 99.9% achieved within 10 min of treatment at 1.13 mA/cm2 current density. Morphological, elemental analysis of the electrode surface and formed sludge confirmed that less sludge was generated during Pb(II) removal from simulated wastewater by the proposed electrocoagulation system under the optimal conditions.

Evolutionary prediction of electrocoagulation efficiency and energy consumption probing

Evolutionary prediction of electrocoagulation efficiency and energy consumption probing

Removal of thiocyanates and heavy metal ions from simulated wastewater solutions by electro- and peroxyelectrocoagulation

A procedure for treatment of simulated wastewater solutions to remove Cu2+, Ni2+, and SCN− ions using various combinations of aluminum and iron electrodes in the electro- and peroxyelectrocoagulation processes was studied. The influence exerted by the current density, pH of solution, and concentrations of impurities and hydrogen peroxide on the efficiency of removal of these ions was analyzed. Electrocoagulation using aluminum anode does not lead to a significant decrease in the thiocyanate concentration. In the peroxyelectrocoagulation process, the efficiency of removal of SCN− ions increases with an increase in the [H2O2]: [SCN−] ratio. The electrocoagulation efficiency with the Fe/Fe electrode pair reaches 87% for SCN− and 99.5% for Cu2+ and Ni2+ at a current density of 20 mA cm–2 and electrolysis time of 20 min.

Removal of heavy metal ions from aqueous solutions by electrocoagulation using Al and Fe anodes

Electrocoagulation treatment of model wastewater solutions to remove jointly present Cu2+ and Ni2+ ions was studied. The influence of the current density, concentration of impurities, anode material, and structure of the precipitate of coagulant metal hydroxides on the efficiency of removal of the heavy metal ions was examined. The decisive factor under the chosen process conditions is the anode material. The electrocoagulation efficiency is considerably higher when using the aluminum anode, compared to the iron anode.

Electrocoagulation efficiency and energy consumption probing by artificial intelligent approaches

Color removal efficiency (CR%) and energy consumption (EnC) of Electrocoagulation (EC) were investigated using synthetic wastewater, containing disperses like orange 25 dye (DO25). Five operational parameters including initial pH (pH0) (2, 5.5, and 9), initial dye concentration (C0) (20, 60, and 100 mg L−1), applied voltage (VEC) (10, 20, and 30 V), initial electrolyte concentration (CS) (0, 1.5, and 3 g L−1), and treatment time (tEC) (0, 0.5, 5, 10, 15, 25, 35, and 50 min) were probed as more effective operational parameters of EC. Combined design of experiments (DOE) was designed and experiments were conducted in accordance with it. The experimental data were obtained in a laboratory through a handmade batch reactor. The achieved CR% (0–99.9) and EnC (0–69.4 wh) were gained under experimental conditions. The optimum value of C0 was almost 20 ppm (minimum range). Two optimum clusters could be discriminated for other four parameters. First group was corresponded to conditions with pH0 = 9 (maximum value of range), CS = 0.7–1.1 (g/lit), VEC = 10 V (minimum of range), and tEC = 1 min. Second group was corresponded to the conditions with pH0 = 6.8 (except two cases), CS = 1.1–2 (g/lit), VEC = 10–15.2 V, and tEC = 49.4–50 min. The data was used for model building by employing two more popular models in this study: reduced quadratic multiple regression model (SMLR) and artificial neural network (ANN). Further statistical tests were applied to exhibit models’ goodness and to compare the models. Based on statistical comparison, ANN models obviously outperformed SMLR models. Finally, multi objective optimization of CR% and EnC was carried out using genetic algorithm (GA) over the outperformed ANN models. The optimization procedure causes nondominated optimal points, which gave an insight into optimal operating conditions of the EC.

Electro-coagulation treatment of oily wastewater with sludge analysis

Experiments were carried out in a batch reactor to treat the oily effluent by electro-coagulation. The influence of operating parameters such as applied current, type of electrode and electrolysis time on electro-coagulation efficiency has been critically examined. The maximum percentage removal of chemical oxygen demand (COD) was 94% under optimum experimental conditions of pH 6.7, current density 6 mA/cm², electrolysis time 40 min, and using mild steel as anode. The remaining sludge in the reactor was analyzed by energy disperse analysis of X-rays (EDAX) and scanning electron microscope (SEM) analysis. The analysis confirms that the oily pollutant was removed by electroflotation and adsorption of the oily particles of precipitate during the electro-coagulation process. Electro-coagulation can be used as an efficient treatment technique for oily wastewater.

Efficiency of a Pretreatment by Electrocoagulation with Aluminum Electrodes in a Nanofiltration Treatment of Polluted Water

The decrease of quality and availability of waters induces the research of hyphenated technologies for improving purification processes. The paper is devoted to the water treatment of a lack which accumulates a diversified pollution arising from a lot of industries. The investigated lack water contained heavy metals, fecal bacteria and high chemical pollution as measured by its chemical oxygen demand (COD). An electrocoagulation was applied as water pretreatment of a nanofiltration process. The electrocoagulation was carried out in a batch experiment with two parallel aluminum plates of 15cm2. Water analysis showed a decrease of the COD from 60 to 5mg L-1, depending upon current density, current charge and solution pH. Thanks to electrocoagulation efficiency, the most probable number (MPN) of bacteria decreased from 2500 to 2 MPN/100mL. This disinfection allowed the performing of a continuous coupling treatment of electrocoagulation and nanofiltration by using a cylindrical aluminum anode and an organic Nanomax50 membrane respectively.

Effect of modification of textile wastewater composition on electrocoagulation efficiency

This paper deals with the efficiency of electrocoagulation (EC) for the abatement of COD, TOC, absorbance (i.e. color) and turbidity from a real textile wastewater, a pure red dye solution (disperse dyes 2-naphthoic acid and 2-naphthol) and a solution combining the two above fluids. The treatment of the dyestuff solution is satisfactory with high levels of color and organic pollution abatement. The treatment of the industrial waste is less efficient. Treatment of the solution combining the two above fluids allows to investigate whether the removal of several polluting matters by electrocoagulation could be considered as the superimposition of the various treatments of single-species effluents, in sort of additivity principle, as presented in an original model for the treatment of two-pollutant waste. Turbidity and TOC were shown to be additive variables in the treatment of the dye solution and the industrial textile waste: electrocoagulation seems to proceed with no interaction between the two types of matter to be removed, namely the dye stuff, and the lot of pollutants contained in the industrial waste.

Influence of different combinations of aluminum and iron electrode on electrocoagulation efficiency: Application to the treatment of paper mill wastewater

Abstract The effective performance of electrocoagulation (EC) technique in the treatment of paper mill wastewater has been investigated using different combination of aluminum (Al) and iron (Fe) electrodes. The influence of pH, temperature and current density on removal performance was explored. The optimum working pH was found to be in the range 5–7, allowing paper mill wastewater to be treated directly without pH adjustment. In addition, it is found that an increase in the current enhanced the speed of the treatment significantly. However, simultaneous increase of electrode and energy consumption was observed. The optimum current density allowing the quickest treatment with a low cost was found to be 70 mA cm− 2. Therefore, a current density of 70 mA cm− 2 was selected as an optimum that allows fast and low cost treatment. Also temperature has negative effect on the removal efficiency.

Design development of an electrocoagulation reactor for molasses process wastewater treatment

The impact of electrode corrosion behaviour, reactor geometry and current density on electrocoagulation efficiency were investigated for the treatment of molasses process wastewater. Two laboratory-scale vertical plate electrocoagulation reactors were used for this investigation: the first being a low aspect ratio bath reactor with a low specific electrode area, while the other was a high aspect ratio column reactor with a high specific electrode area. Anomalous anodic dissolution and cathodic corrosion of the aluminium electrodes both contributed significantly to overall metal consumption. Increasing specific electrode area and aspect ratio each led to improved treatment efficiency, whereas the impact of current density was more complicated involving the combined influences of several competing effects. The space-time yields of coagulant and bubbles (both functions of specific electrode area, current density and current efficiency) were found to influence mixing within the reactor and thus treatment efficiency.

Removal of Ni, Cu and Cr from a galvanic wastewater in an electrocoagulation system with Fe- and Al-electrodes

The performance of an electrocoagulation system for Ni, Cu and Cr removal from a galvanic wastewater in laboratory scale was studied systematically. Several parameters – such as electrode material and arrangement, initial pH, charge loading and applied current – and their influence on the cleaning results and on the electrocoagulation efficiency were investigated. The results with the galvanic wastewater (2 g/l Ni, 2.5 g/l Cu and 0.7 g/l Cr at pH 1.5) revealed that the best cleaning results and the most effective removal could be achieved with a combination of Fe- and Al-electrodes and an pH initial > 5.0. This approach combined the advantages of both the single set-ups: the pH increase with the Al-electrodes at high currents, the possibility of a Cr(VI)-reduction by Fe 2+ and probably a better co-precipitation by Al- and Fe-hydroxides, respectively. An increase of the current accelerated the removal process. With Fe-electrodes at 0.2 A, Al-electrodes at 1.5 A and pH initial of 5.0, the residual metal concentrations after 180 min were 1.5 mg/l Cr, 6.5 mg/l Cu and 65.3 mg/l Ni at a power consumption of 9.0 kWh/m 3.

Electrocoagulation efficiency of the tannery effluent treatment using aluminium electrodes

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 2(3) 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.