Electrocoagulation Research Articles

Prediction of electrocoagulation treatment of tannery wastewater using multiple linear regression based ANN: Comparative study on plane and punched electrodes

This study investigated the electrocoagulation (EC) treatment of tannery wastewater using plane and punched aluminum and iron electrodes at the optimum condition of pH 9, voltage 20 V, electrode distance of 1 cm and 90 min electrolysis duration. The efficiency of the EC process was determined by evaluating the levels of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and Chromium (Cr) in the treated effluents. The experiment utilized both linear regression and Artificial Neural Network (ANN) models for modeling, with the ANN model validating the predicted model from the experimental design with 95 % confidence. The use of plane aluminum electrodes resulted in an optimum removal efficiency of BOD (89.66 %), COD (96.21 %), Cr (96.05 %), and TDS (95.77 %). On the other hand, the punched electrodes achieved a removal efficiency of 90.86 % (BOD), 98.62 % (COD), 96.94 % (Cr), and 96.92 % (TDS). Similarly, when using plane iron electrodes, the removal efficiency of BOD, COD, Cr and TDS was 87.57 %, 94.77 % 93.42 % and 93.08 %, respectively, while punched iron electrodes removed 89.01 % of BOD, 96.59 % of COD, 94.66 % of Cr and 95 % of TDS. The results demonstrate that the proposed ANN effectively predicts effluent BOD, COD, Cr and TDS, addressing economic and environmental sustainability concerns.

Electrocoagulation-photocatalysis sequential combined method for the removal of anticancer drugs from pharmaceutical wastewater using NH2-MIL-125(Ti)/cobalt ferrite nanorods composite photocatalyst

This research reports that the novel NH2-MIL-125(Ti)/cobalt ferrite nanorods composite photocatalyst based on metal-organic framework (MOF) has been synthesized by the microwave heating method. Herein, the sequential electrocoagulation (EC)-photocatalysis combination method was used to remove the chemical oxygen demand (COD), doxorubicin hydrochloride (DOX), and 5-Fluorouracil (5-FU) antineoplastic drugs from wastewater by the composite photocatalyst under a simulated sunlight irradiation. The synthesized photocatalysts were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Brauner-Emmet-Teller surface area analyzer, vibrating sample magnetometer, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, transient photocurrent response, and electrochemical impedance spectroscopy. In the EC process, three-level, three-factor Box-Behnken design was used to investigate the interaction effects of pH (3−8), time (10–60 min), and current density (100–200 A/m2) on the removal of contaminants. The maximum experimental removal efficiencies of COD, DOX, and 5-FU were 68.2 %, 21.1 %, and 24.5 %, respectively, under EC time of 60 min, pH of 5.98, and current density of 176.77 A/m2. About 99.2 % COD, 93.8 % DOX, and 97.0 % 5-FU were removed from pharmaceutical wastewater using NH2-MIL-125(Ti)/ cobalt ferrite nanorods photocatalyst under cobalt ferrite content of 0.288 g, reaction time of 58.48 min, pH of 7.54, and catalyst dosage of 0.5 g/L. The obtained results demonstrated that the combined process of EC and photocatalysis in the presence of MOFs-based photocatalysts is an effective treat strategy for the pharmaceutical wastewater.

Comprehensive study on the selection and performance of the best electrode pair for electrocoagulation of textile wastewater using multi-criteria decision-making methods (TOPSIS, VIKOR and PROMETHEE II)

The accelerating environmental impact of the textile industry, especially in water management, requires efficient wastewater treatment strategies. This study examines the effectiveness of various electrode pairs in the Electrocoagulation (EC) process for treating textile wastewater, focusing on removing of Total Suspended Solids (TSS), turbidity, Chemical Oxygen Demand (COD), and Total Organic Carbon (TOC). A comprehensive analysis was conducted using thirty-six electrode pair combinations, consisting of six materials: Aluminium (Al), Zinc (Zn), Carbon (C), Copper (Cu), Mild Steel (MS), and Stainless Steel (SS). The results demonstrated that different electrode pairs yielded varying removal efficiencies for various pollutants, with the highest efficiencies being 92.09% for COD (Al–C pair), 99.66% for TSS (Al–Cu pair), 99.17% for turbidity (Al-MS pair), and 70.99% for TOC (SS-SS pair). However, no single electrode pair excelled in removing all pollutant categories. To address this, three Multi-Criteria Decision Making (MCDM) methods such as TOPSIS, VIKOR, and PROMETHEE II were used to assess the most effective electrode pair. The results indicated that the Al–Zn combination was the most efficient, exhibiting high removal efficiencies for various pollutants (99.32% for TSS, 98.88% for turbidity, 68.62% for COD, and 57.96% for TOC). This study demonstrates that the EC process can effectively treat textile effluent and emphasizes the importance of selecting suitable electrode materials. Furthermore, pollutant removal was optimal with the Al–Zn electrode pair, offering a balanced and efficient approach to textile wastewater treatment. Thus, MCDM methods offer a robust framework for assessing and optimizing electrode selection, providing valuable insights for sustainable environmental management practices.

Electrocoagulation employing recycled aluminum electrodes for methylene blue remediation

This work focuses on the recycling of aluminum-based metal joinery waste in the context of the treatment of wastewater containing organic materials, such as dyes, by electrocoagulation (EC); aluminum scraps were used as electrodes to process synthetic solutions of the methylene blue (MB) dye. The study investigated the effect of different parameters, including pH (3, 4, 5, 7, 9, 11) current density (100, 150, 200, 250 A/m2), electrolysis time (30, 60,120 min), sodium chloride concentration (0.5, 1, 2 g/L) and the initial dye concentration (10, 20, 45, 60 mg/L) on the removal efficiency of MB. The results showed that the optimum conditions for MB removal were achieved at the original pH of the solution which is 7 using a current density of 200 A/m2 and an inter-electrode distance of 1 cm with 10 mg/L as a dye concentration and 2 g/L of electrolyte. The removal efficiency under these conditions can reach 97.81 %. An estimation was made of the electrical energy needed to attain the ideal removal, which was found to be approximately 0.97kWh/g removal dyestuff the electrode consumption was 0.13 (kgAl /g of dyestuff), with an operation cost of 0.106 ($/g of dyestuff). The study suggests that EC using only two aluminum electrodes is efficient technique for the removal of MB from synthetic wastewater. The removal of the dye was monitored by UV–visible spectroscopy and scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) is used for the identification of the functional groups of MB in the obtained sludge by the EC process; and the aluminum electrodes surfaces, before and after treatment, were characterized by scanning electron microscopy (SEM) and Dispersive Energy Spectroscopy (EDS).

Once through continuous mode electrocoagulation for tannery wastewater remediation: Process optimization and performance evaluation

The treatment of wastewater from tannery industries poses significant challenges due to high levels of tannic acid and chemical oxygen demand (COD), along with low biodegradability. To address this issue, we conducted a study focusing on the use of Electrocoagulation (EC) as a treatment process for synthetic tannery wastewater. Iron (Fe) electrodes have been used as anode and cathode as well. The electrodes size (7 cm × 7 cm) has been used in this process. The investigation of removal efficiencies entailed the assessment of total organic carbon (TOC) and chemical oxygen demand (COD) as indicators of organic contaminant levels within the wastewater. The influence of current density, pH, flowrate, and time on the treatment was measured. At a current density of 51 A/m2 with 83.54 % of COD removal and 27 % of TOC removal were observed. The maximum COD removal was found at pH 4.93, flowrate 5 ml/min, current 0.953 A and time 115 min. The current investigation demonstrated the efficacy of the electrocoagulation process in reducing both total organic carbon (TOC) and chemical oxygen demand (COD) levels in synthetic tannery wastewater.

Low-maintenance anti-scaling of nanofiltration pretreated by bipolar-induced electrolysis for decentralized water supply

Nanofiltration (NF) offers an effective solution to ensure a decentralized water supply. However, its reliance on dosing for pre-precipitation and anti-scaling severely complicates its maintenance, adding to its cost and limiting its application, especially in rural areas. In this study, a bipolar-induced electrolysis (BIE) pretreatment method was developed to reduce the NF membrane scaling potential without the need for additional reagents. The water flux of the BIE-NF increased by 24.2 ± 6.5 % compared to traditional NF. This benefits from the synergistic effects of electrocoagulation (EC) and electro-precipitation (EP) of BIE to remove hardness ions (36.8 ± 0.7 g CaCO3 m−2 h−1), 26.2 ± 2.6 % and 16.1 ± 4.7 % faster than that of traditional EP and EC, respectively, exhibiting robust resistance to the interfering ions and organics. The unit energy consumption of BIE was only 18.9 ± 1.0 kWh/(kg CaCO3), 11.8 ± 1.9 % and 67.0 ± 1.4 % lower than that of EP and EC, respectively. After BIE electrolysis, the Ca, humic acid, and Mg contents were dramatically reduced, and a uniformly loose fouling layer formed on the NF membrane, demonstrating alleviated membrane scaling. Remarkably, BIE softening demonstrated its stability and feasibility in sustaining 120.0 m3/d of drinking water to rural populations without requiring additional reagents or manual maintenance, minimizing the operation and maintenance cost to 5.1 US cents/m3 water, 29.0 % lower than the cost of conventional dosing pretreatment. This study offers a low-cost and sustainable method for water supply through decentralized membrane purification.

Leachate treatment via electrocoagulation–coal‐based powdered activated carbon process: Efficiencies, mechanisms, kinetics, and costs

AbstractThis study aims to improve COD, NH3‐N, and turbidity removal from Bingöl's leachate using a single‐reactor integrated electrocoagulation (EC)–coal‐based powdered activated carbon (CBPAC) process under various experimental conditions. In the EC‐CBPAC process, three stainless‐steel cathodes and three aluminum electrodes were connected to the negative and positive terminals of the power supply, respectively. The initial concentrations in the leachate were 1044 mg O2/L for COD, 204 mg/L for NH3‐N, and 57 NTU (or 71.25‐mg (NH2)2H2SO4/L) for turbidity, respectively. After a 40‐min EC‐CBPAC process, with a CBPAC dosage of 5 g/L and pH of 5 for COD and turbidity, and 9.5 for NH3‐N, the optimum removal efficiencies for COD, NH3‐N, and turbidity were achieved at 92%, 40%, and 91%, respectively. When the EC process was applied without CBPAC under the same experimental conditions, the removal efficiencies of COD, NH3‐N, and turbidity were 87%, 28%, and 54%, respectively. Before and after the EC‐CBPAC process, the Brunauer–Emmett–Teller (BET) surface area, pore volume, and mean pore diameter of the CBPAC were found to be (888 m2/g, 0.498 cm3/g, and 22.28 Å) and (173 m2/g, 0.18 cm3/g, and 42.8 Å), respectively. The optimum pseudo‐first‐order (PFO) rate constants for COD, turbidity, and NH3‐N were determined to be 3.15 × 10−2, 4.77 × 10−2, and 8.8 × 10−3 min−1, respectively. With the current density increasing from 15 to 25 mA/cm2, energy consumption, unit energy consumption, and total cost increased from 68.7 to 122.4 kWh/m3, 6.948 to 15.226 kWh/kg COD, and 0.85 to 1.838 $/kg COD, respectively.Practitioner points EC‐CBPAC process has greater COD, NH3‐N, and turbidity removal efficiency than EC process. COD and turbidity achieved their optimum disposal efficiencies at 92% and 91%, respectively, at pH 5 The most efficient disposal efficiency for NH3‐N was observed to be 40% at pH 9.5. EC‐CBPAC process increased removal efficiencies for COD, NH3‐N, and turbidity by 20%, 19%, and 38%, respectively, compared with EC alone. The turbidity, NH3‐N, and COD disposal fitted PSO model due to high correlation values (R2 0.94–0.99).

Ultrasonically Assisted Electrocoagulation Combined with Zeolite in Compost Wastewater Treatment

In this paper, the possibility of combining electrocoagulation (EC), ultrasound, and the addition of zeolite for wastewater treatment was investigated for the first time. The following combinations of hybrid processes were tested: electrocoagulation with zeolite (ECZ), simultaneous electrocoagulation with zeolite and ultrasound (ECZ+US), and two-stage electrocoagulation with zeolite and ultrasound (US+Z - EC), carried out with three different electrode materials. The results show that the simultaneous assistance of ultrasound in the ECZ leads to a lower increase in pH, while the temperature increase is higher. Regarding the COD, the assistance of ultrasound is only useful for Zn electrodes in the two-stage US+Z - EC, while the reduction in voltage consumption occurs for Fe and Al electrodes. Ultrasonic assistance caused more damage to the anodes, but anode consumption was reduced for Al and Zn electrodes. The total amount of zeolite that can be recovered is between 55–97%, and recovery is higher in systems with higher turbidity reduction. Good settling ability is only achieved with Al and Fe electrodes in simultaneous performance. Taguchi’s orthogonal L9 array design was applied to analyze the effects of electrode material, process type, mixing speed, and time duration on COD decrease, settling velocity, electrode, and voltage consumption. The results show that the use of ultrasound does not contribute to the desired result and generally only has a favorable effect on voltage and electrode consumption, while it has no positive effect on settling ability or COD decrease. Furthermore, although longer times and higher mixing speeds negatively impact cost due to voltage and electrode consumption, it is advisable not to choose the shortest duration and lowest speed to obtain adequate wastewater treatment quality.

Heavy Metal Ion Adsorbent in Aqueous Solution: A Review on Chitosan and Chitosan Composites

One prominent contributor to environmental degradation is the presence of heavy metal ions, which are commonly introduced into ecosystems through diverse channels, including mining operations, paint manufacturing, battery production, and agricultural practises. The unprocessed waste from these industries typically undergoes direct discharge into rivers and seas, thereby adversely influencing the potable water supply and marine ecosystem. This results in the accumulation of heavy metals within living organisms and subsequent environmental degradation that poses a significant risk to human health, as their prolonged consumption can harm various organs and the nervous system. Therefore, the United States Environmental Protection Agency (US-EPA) and the World Health Organisation (WHO) have established stringent regulations regarding the allowable levels of heavy metal intake, particularly concerning potable water consumption. The imperative lies in surmounting this challenge by discovering the optimal technique for extracting heavy metals. This paper examines the primary methods of eliminating heavy metal ions using chitosan-based materials. Specifically, the methods under scrutiny include electrocoagulation (E.C.), bioremediation, ion-exchange, membrane filtration (purification), and adsorption. Adsorption, as a highly efficient method, presents itself as a viable strategy for the remediation of dyes in textile wastewater due to its advantageous characteristics. Notably, this approach obviates the need for extensive spatial requirements and exhibits a commendably swift treatment duration. Chitosan exhibits promising adsorptive characteristics owing to its advantageous physical attributes, including crystalline structure, porous nature, and particle dimensions, all of which synergistically enhance the adsorption capacity of chitosan. Research findings indicate that the adsorption characteristics of chitosan are subject to variation contingent upon the distinct heavy metal ions under consideration and the specific experimental parameters employed. Hence, optimising these parameters becomes imperative to attain enhanced chitosan adsorption capabilities for heavy metal ion removal.

Aluminum Waste as Electrode for Home Textile Industry Wastewater Treatment using Batch Electrocoagulation Process: Studies on Operating Parameters

The manufacture of the Sasirangan home textile industry involves coloring and dyeing processes using synthetic dyes in large quantities. These contaminants of dyes and organic materials would cause high color and chemical oxygen demand (COD) contaminants values. This study aims to characterize the wastewater of batik-modified Sasirangan and determine the effect of current density and length of operating time on color removal and reduction of COD in Sasirangan home textile industry wastewater through the batch electrocoagulation process. The method used in this research is an electric current flowing in the same direction to the Sasirangan home textile industry wastewater in a reactor with dimensions of 310 180 240 mm3. The electrode used is aluminum alloy type 1100. The aluminum/aluminum (Al/Al) electrode is used in this electrocoagulation (EC) process, then connected to a direct current (DC) power supply. The experiment was carried out at room temperature using an electrode distance of 2 cm with variations in the time of the electrocoagulation process for 15–120 minutes. The experiment was repeated for variations in pH (4–9) with a current density of 3.5–5.5 mA/cm2. Furthermore, an analysis of the color removal and the decrease in the concentration of COD was carried out. The results showed that the contaminant content in Sasirangan home textile industry wastewater decreased significantly, whereas the optimal conditions for the EC reaction were determined using color and COD removal efficiency parameters. The decrease in color and COD concentrations occurred at a current density of 5.5 mA/cm2 with a pH of 4 for 120 minutes, around 1110 PtCo and 90.4 mg/L of COD, respectively

Study on COD and color removal efficiency in textile dyeing wastewater by iron electro-coagulation technology combined with persulfate

Electrocoagulation (EC) is an attractive method for treating many types of wastewater due to its advantages. The purpose of this study is to investigate the effect of persulfate addition on the efficiency of textile wastewater treatment through the removal percentage of COD and color parameters. Persulfate is proven to significantly enhance the rate and efficiency of pollutant removal in textile wastewater. The removal percentage of COD could reach 91.33 ± 1.23% and 97.99% ± 0.52% was the highest removal percentage of the color parameter at the optimal reaction parameters. The effluent concentration meets the standards according to Vietnam national technical regulation on textile industry wastewater. By using persulfate, the COD and color removal efficiency increased by 17.53 ± 2.69% and 8.81 ± 0.91%, respectively, compared to the single electrocoagulation process. The amount of sludge generated in the system is 0.542 ± 0.0357 kg/m3, significantly reduced compared to the flocculation process of 0.875 ± 0.0295 kg/m3.

Degradation of levofloxacin using electro coagulation residuals-alginate beads as a novel heterogeneous electro-fenton composite

The presence of levofloxacin (LEV) in aqueous solutions can pose health risks to humans, have adverse effects on aquatic organisms and ecosystems, and contribute to the development of antibiotic-resistant bacteria. This study aims to investigate the feasibility of using electrocoagulation residuals (ECRs) as a heterogeneous catalyst in the electro-Fenton process for degrading LEV. By combining electrocoagulation residuals with sodium alginate, ECRs-alginate beads were synthesized as a heterogeneous electro-Fenton composite. The response surface method was employed to investigate the optimization and influence of various operating parameters such as the initial concentration of LEV (10–50 mg/L), voltage (15–35 V), pH (3–9), and catalyst dose (1–9 g/L). The successful incorporation of iron and other metals into the ECRs-alginate beads was confirmed by characterization tests such as EDX and FTIR. By conducting a batch reaction under optimal conditions (initial LEV concentration = 20 mg/L, pH = 4.5, voltage = 30V, and catalyst dose = 7 g/L), a remarkable degradation of 99% for LEV was achieved. Additionally, under these optimal conditions, a high removal efficiency of 92.3% for total organic carbon (TOC) could be attained within 120 min and these findings are remarkable compared to previous studies. The results further indicated that the degradation of levofloxacin (LEV) could be accurately quantified by utilizing the first-order kinetic reaction with a 0.03 min−1 rate constant. The synthesized beads offered notable advantages in terms of being eco-friendly, simple to use, highly efficient, and easily recoverable from the liquid medium after use.

Mn-assisted Fe-electrocoagulation strategy for enhanced efficient arsenic removal and its mechanism

Electrocoagulation (EC) is a facile technique for removing arsenic (As) pollutants from different water matrices with high efficiency. In this work, a novel strategy of Mn-assisted Fe EC was developed to further enhance the removal efficiency of arsenite [As(III)] from wastewater. When 1 mM of MnCl2 was added to an Fe-EC system, the As removal efficiency reached 99.99%, and the residual concentration was only 9 μg/L, which is lower than the World Health Organization’s limit for drinking water. The characteristics of the generated flocs by four different EC processes in Fe, Fe-Mn, Fe-As, and Fe-Mn-As systems were investigated. The results showed that Mn2+ promoted the formation of FeOOH, FeOx, MnOx, FeHAsO4, and MnHAsO4 through low crystallinity and a high surface area. Density functional theory simulation and crystal orbital hamiltonian population confirmed that the generated Fe-Mn flocs had a greater adsorption affinity for As(III) and arsenate [As(V)]. The possible reactions in the EC processes and reaction mechanisms were also hypothesised. The current work provides meaningful insights into understanding the mechanisms of Mn-assisted Fe-EC systems, and further confirms its potential for practical applications in As pollution treatment.

Treatment of electroplating wastewater using electrocoagulation and integrated membrane.

Electroplating wastewater contains heavy metal ions and organic matter. These contaminants not only endanger the environment but also pose risks to human health. Despite the development of various treatment processes such as chemical precipitation MBR, electrocoagulation (EC) ceramic membrane (CM), coagulation ultrafiltration (UF) reverse osmosis (RO), and CM RO. These methods are only effective for low concentrations of heavy metals and struggle with high concentrations. To address the challenge of treating electroplating wastewater with high heavy metal content, this study focuses on the wastewater from Dongfang Aviation Machinery Processing Plant. It introduces an EC and integrated membrane (IM) treatment process for electroplating wastewater. The IM comprises microfiltration (MF) membrane, nanofiltration (NF) membrane, and RO membrane. Results indicated that under specific conditions, such as a pH of 8, current density of 5 A/dm2, electrode plate spacing of 2 cm, 35 min of electrolysis time, and influent pH of 10 for the IM, removal rates of Zn2+, Cu2+, Ni2+, and TCr in the wastewater exceeded 99%. The removal rates of chemical oxygen demand (COD), suspended solids (SS), total phosphorus (TP), total nitrogen (TN), and petroleum in wastewater exceed 97%. Following a continuous cleaning process, the membrane flux can consistently recover to over 94.3%.

Revealing the characteristics of coagulant and ·OH generation in the electrocoagulation coupled with E-peroxone process and comparison of the synergistic effect for water purification

Electrocoagulation (EC) coupled with E-peroxone process (ECP) offers a promising approach for simultaneous coagulation and oxidation, enhancing contaminant removal efficiency and current efficiency within a single electrochemical system. However, understanding the production characteristics of active species and their synergistic effects remains limited. This study comprehensively investigated the production of active species (i.e., ·OH and coagulant) during the ECP process and explored their synergistic effect in real water purification. Increasing current density and O3 dosage led to significant enhancements in ·OH and Alb production. The synergistic factor (β) for ·OH production ranged from 1.68 to 1.73 for lower current density and from 1.19 to 1.32 for higher current density, while β for ·OH production in ECP increased from 0.77 to 1.16–1.19 with increased O3 dosage. Besides O3 decomposition and cathodically-induced H2O2 production, alternative pathways contributed to enhanced ·OH production and synergistic effects. The Al-based coagulant facilitated the reaction with O3, initiating a chain reaction for ·OH and Alb production. Furthermore, the feasibility and synergistic effects of ECP for two water matrices (surface water and shale gas produced water) were compared. ECP exhibited superior performance for both matrices, with TOC removal exceeding 63.2 % for surface water and 87.0 % for shale gas produced water. The study provides deeper insights into the ECP process, highlighting its potential for sustainable water treatment.

Degradation of the neonicotinoid pesticide imidacloprid by electrocoagulation and ultrasound

Imidacloprid is still a widely used neonicotinoid insecticide that is banned in many countries because of the associated environmental risks. Due to the inefficiency of conventional wastewater treatments for pesticide removal, new treatment methods are being investigated. Electrochemical methods, including electrocoagulation (EC), seem to be promising alternatives considering their effectiveness in removing various pollutants from wastewater. The aim of this study was to investigate the effects of electrode material, current density, ultrasound, and operation time on the efficiency of imidacloprid removal from a model solution by EC. The combination of aluminum electrodes and 20 A of applied current for 20 min resulted in total imidacloprid degradation. A simplified energy balance was introduced as a form of process evaluation. Combining ultrasound with EC resulted in 7% to 12% greater efficacy than using only EC.

Optimizing electrocoagulation for poultry slaughterhouse wastewater treatment: a fuzzy axiomatic design approach

White meat consumption is increasing day by day, and accordingly, there is an increase in the amount of wastewater resulting from the processes. Today, the reuse of wastewater has become a goal within the scope of the Green Deal. For this reason, wastewater treatment with high pollution and volume has gained importance. In this study, the fuzzy axiomatic design (FAD) method, one of the multi-criteria decision-making methods, has been used. With this method, coagulation, electrocoagulation (EC), dissolved air flotation (DAF), and anaerobic treatment alternatives preferred in poultry slaughterhouse wastewater (PSW) treatment were compared with each other and their information contents were calculated. The information content from the smallest to the largest is EC, DAF, coagulation, and anaerobic treatment, respectively. This treatment method was chosen because the smallest information content is in electrocoagulation. EC was applied to bloody PSW containing 1% blood by volume. The effectiveness of Fe and Al electrodes for PSW treatment in the batch EC reactor has been compared. The effective surface areas of 2 anodes and 2 cathodes connected bipolarly in the processes are 288 cm2. The electrolyte, pH, time, and current density effects on energy consumption were also investigated. The optimum conditions for Al and Fe electrodes were found to be 0.5 g·L−1 NaCl concentration, pH 5, 0.639 mA·cm−2 current density, and 5 min time. Under optimum conditions for the Fe electrode, COD, TOC, TN, and oil-grease removal efficiencies were determined as 76.3%, 71.8%, 70%, and 74%, respectively. Moreover, the highest COD, TOC, TN, and oil-grease removal efficiencies were achieved with an Al electrode (82.2%, 82.3%, 82.7%, and 78.9%, respectively). The experimental data were fit to a variety of isotherms and kinetic models to determine the characteristics of the EC. The results indicated that the pseudo-second-order equation provided the best fit for COD removal. Under optimum conditions, the operating cost was calculated as $3.39 and $3.09 for Al and Fe electrodes, respectively. In this study, the fuzzy axiomatic design method was used for the first time to select the most appropriate treatment method for PSW. In addition, blood, a major problem for the poultry slaughterhouse industry, was mixed with PSW at a ratio of 1% (v/v) and treated with EC for the first time with high removal efficiency. By treating PSW, which has a high pollution load, with electrocoagulation, the pollution load of the water to be given to secondary treatment has been greatly reduced.

Evaluation of the impacts of seawater integration to electrocoagulation for the removal of pollutants from textile wastewater

Recent textile industry expansion has a major environmental impact if not addressed. Being a water intensive industry, textile manufacturing is usually associated with wastewater management challenges. Electrocoagulation (EC) is recognized as one of the effective solutions to address these challenges. This study aims to investigate the potential of integrating seawater into the EC process for textile wastewater treatment, targeting optimal pollutant removal efficiencies. A simple electrolytic reactor was designed to investigate the removal efficiency of these treatments for chemical oxygen demand (COD), total suspended solids (TSS), turbidity, and color from textile wastewater at different seawater percentages and retention times. Notably, the addition of seawater not only improves the EC process efficiency but also significantly dilutes pollutants, reducing their concentrations. This dual effect enhances removal efficiency and dilution optimizes the treatment outcome. The highest removal efficiencies were achieved for COD (47.26%), TSS (99.52%), turbidity (99.30%), and color (98.19%). However, pH, dissolved oxygen (DO), and electrical conductivity increased with increasing retention times and seawater percentages in the EC process. Moreover, Seawater − EC integration reduces power usage to 15.769 Am−2 and costs approximately 0.20 USD/m3. To assess the effects of the retention times and seawater percentages on pollutant removal from textile wastewater, an analysis of variance (ANOVA) was conducted utilizing the Design-Expert 11 software. The best model obtained using Central Composite Design (CCD) was quadratic for COD (R2 = 0.9121), color (R2 = 0.9535), turbidity (R2 = 0.9525), and TSS (R2 = 0.9433). This study suggests that higher seawater percentages and longer retention times effectively eliminate contaminants but increase ion concentrations.

Defluoridation of tap water by electrocoagulation and fluoride adsorption on aluminum hydroxide flocs

ABSTRACT Overload of fluoride ions in water is observed in several regions of southern Tunisia, mainly the regions close to the mining basin of Gafsa: Metlaoui, Omlarayes and Redayef. This study concerns fluoride removal from Metlaoui's tap water by electrocoagulation (EC) using aluminum electrodes in a batch reactor. This water contains 3.5 mg·L−1 of fluoride, the highest concentration observed in these basins. The effect of the operating conditions of EC treatment on tap water defluoridation was analyzed, namely, current density, temperature and interelectrode distance. Hydroxide aluminum flocs, formed with different durations of EC, were used as sorbents in fluorinated deionized water ([F−] = 3.5 mg·L−1) and Metlaoui's tap water. Flocs formed after 30 min of EC, produced by dissolving (79 ± 1) mg·L−1 of aluminum and adjusted at pH = 6.5, allowed the adsorption of (98 ± 1)% of fluoride ions from deionized fluorinated water. Flocs adjusted at different pH, from 5 to 9, were used as sorbents in fluorinated deionized water and Metlaoui's tap water. Acidic and neutral flocs allowed the best yields of fluoride adsorption. Contrary to the literature, this work highlighted the absence of ion exchange of hydroxide anion by fluoride anion in water, highlighting a mechanism of physical adsorption on aluminum hydroxide flocs.

The effect of voltage on polypropylene microplastics removal by electrocoagulation process using Fe electrode

This study investigates the effect of voltage on the removal of polypropylene microplastics (PPMPs) from artificial wastewater via an electrocoagulation (EC) process using iron (Fe) electrodes. The effect of the voltage was investigated by conducting multiple continuous flow experiments at three different voltage values (10, 20, and 30 V). The findings demonstrated that the turbidity value increased gradually as the initial voltage increased, from 6.67 NTU at 10 V to 74.37 NTU at 30 V. In this EC process, in which Fe electrodes are utilized to remove the PPMPs, it is believed that 20 V provides optimal support. Kinetic studies showed that the process followed a first-order kinetic model with a kinetics rate constant (k) of 0.0143 min-1 and a coefficient of determination (R2) of 0.9702. The findings demonstrated that voltage is a significant parameter in the EC process employing Fe electrodes to remove PPMPs from wastewater.