Mechanistic insights into electrocoagulation-driven removal of polystyrene nanoplastics from urban treated wastewater.

Polarity-driven Fe phase transformation in biochar-based electrocoagulation: Toward selective metal recovery from acid mine drainage.

This study investigates the application of electrocoagulation (EC) for treating vegetable washwater (VWW). Preliminary EC experiments were carried out to define the operational parameter ranges supporting a subsequent statistical optimization of the process. The optimization aimed to identify the most efficient operating conditions for pollutant removal while minimizing energy consumption. VWWs were sampled from four root vegetable washings (potatoes, leeks, and red beets). Various EC tests carried out using a 500-mL reactor and a response surface methodology of experiments enabled us to obtain optimum operating conditions for the treatment of VWW. Thus, optimal conditions of a current intensity of 0.32 A for 8.8 min with aluminum electrodes gave total suspended solid (TSS) and turbidity reduction rates of 99% and 98%, respectively, along with a total phosphorus reduction rate of 93% for Farm 1. EC VWW treatment generally met the regulatory discharge limit of 50-mg/L TSS. Only TSS of Farm 4 remained well above the limit. EC also reduced neonicotinoid insecticides present in VWW by 38%, and the true color of beet roots decreased from 283 to 60 UCV. The energy costs associated with VWW clarification treatment ranged between CAD$0.06/m3 and CAD$0.09/m3.

Releasing dye-contaminated textile wastewater into water bodies without proper treatment has adverse effects on the environment and poses serious health risks to living beings. Amaranth is one of the widely used textile red azo dyes in Sri Lanka, and it is discharged improperly because traditional water treatment methods often fall short of effectively removing the dyes due their diverse and persistent nature. Electrocoagulation (EC) provides a promising alternative. Although EC has been widely investigated, no studies has examined the application of carbon-based materials as electrodes. This study aimed to evaluate the application of a carbon felt cathode combined with an aluminium anode for removing the Amaranth azo dye from synthetic textile wastewater. The effect of initial pH, applied potential, stirring speed, and electrolysis time on EC performance were studied to identify the optimal condition, and the results revealed 100% efficiency to remove 20 mg/L dye solution in 30 minutes of electrolysis at 6.4 V, pH 2, and 1000 rpm without any additional electrolytes. The study confirmed successful application of carbon felt as a cathode material and highlights that pH is a crucial factor in generating the types of coagulant species, and the system is self-pH neutralizing with treatment time.

Abstract Rising urbanization and industrialization have led to the discharge of substantial volumes of wastewater into the environment. Consequently, wastewater treatment has become crucial for reducing environmental pollution and ensuring human health by eliminating harmful contaminants. Physical, chemical, and biological methods are used to treat wastewater, and advanced approaches frequently combine these techniques or employ innovative technologies. This article, covering recently published articles from 2000 to 2024 extracted from the Scopus database and analyzed using the ‘bibliometrix’ tool in R, aims to highlight progress in wastewater treatment techniques involving the combined application of electrocoagulation (EC) and adsorption (AD). We observed an increase in research interest in the application of the EC/AD process to treat various wastewater matrices through data visualization using ‘Microsoft Excel,’ ‘biblioshiny,’ and ‘VOSviewer.’ The research highlights significant improvements in the EC/AD process that ensure sustainability by incorporating renewable energies and green adsorbents, as well as efficiency in pollutant removal, including emerging contaminants such as heavy metals, dyes, and pharmaceutical compounds. The increased emphasis on the EC/AD process represents a significant advance in wastewater treatment, reflecting the critical need to address the complexities of modern pollution.

This study evaluated the efficiency of electrocoagulation (EC) in the removal of Reactive Red BF-4B dye, also considering the energy consumption and residual toxicity of the treated wastewater. Batch reactor experiments were conducted using iron electrodes and different electrolytes, and a Box-Behnken experimental design was applied to investigate the effects of pH, electrical conductivity, and operation time, with statistical significance assessed by ANOVA. Under optimized conditions, EC achieved over 99% color removal, with excellent model fitting (R2=0.970) and minimal pH influence. Kinetic analysis indicated rapid decolorization, while total organic carbon (TOC) and total nitrogen (TN) removal required longer electrolysis times. Energy consumption remained moderate, reflecting a favorable balance between efficiency and operational cost. Bioassays with Artemia salina showed a significant reduction in acute toxicity, with the median lethal concentration (LC50) increasing from approximately 33% to 64% over the course of the treatment. These results demonstrate that electrocoagulation is a promising alternative for textile wastewater treatment, combining high efficiency in dye removal, reduction of organic load, and decreased toxicity, with low environmental impact and relevant for practical application.

ABSTRACT The tanning industry is known to have serious environmental effects, as it consumes a significant amount of water, chemicals and dyes, and the resulting tannery wastewater has high total dissolved solids (TDS), chemical oxygen demand (COD), and chromium species. These pose a threat to the ecosystem and human beings. Conventional treatment methods like coagulation, flocculation, and biological processes show limited efficiency and generate contaminated sludge. Hybrid systems combining flocculation, photocatalysis, and membrane filtration offer better performance, but challenges remain in handling high salinity, chromium-rich sludge, and overall operational costs. Electrochemical methods offer an efficient and eco-friendly approach to treating highly saline tannery wastewater containing toxic metals, colour, and refractory organics. Techniques like electrocoagulation (EC), electrochemical oxidation (EO), and electro-fenton (EF) remove pollutants effectively with minimal chemical use. Using sacrificial electrodes (Fe, Al) in EC and inert electrodes (graphite, Ti-MMO, BDD) in EO/EF, these systems generate strong oxidants that degrade complex pollutants, reduce sludge, enhance chromium removal, and provide a scalable, energy-efficient solution. Overall, they offer better control and higher efficiency than conventional wastewater treatment methods. In general, the review suggests the potential of innovative electrochemical treatment methods to achieve effective pollutant removal, resource recovery, and sustainable tannery wastewater treatment.

Hazardous waste landfill leachate (HWLL) can contribute significantly to nitrate contamination in the environment, raising ecological concerns and potential human health risks, particularly through groundwater infiltration and drinking water exposure. This study investigates electrocoagulation (EC) process for effective nitrate (NO3 -) removal, including an assessment of energy consumption. Kinetic models and adsorption isotherms were used to predict NO3 - removal performance. Experiments were conducted using an initial NO3 - concentration of 120 mg/L with varying electrolysis time (ET) and current density (CD). The influence of co-existing ions such as sulfate (SO4 2-), carbonate (CO3 2−), chloride (Cl−), calcium (Ca2+), and magnesium (Mg2+) were investigated. The EC process was optimized at pH of 7.53, an inter-electrode distance (IED) of 2 cm, CD of 15.90 mA/cm2, and an ET of 120 min, achieving maximum NO3 - removal efficiency of 86%. A pseudo-second-order kinetic model with rate constant k (0.006 min−1) and R2 of 0.7986 best described the adsorption behavior. The experimental data for NO3 - removal were assessed using the Langmuir, Freundlich, and Temkin adsorption isotherm models. Adsorption isotherm equilibrium data were best fitted to the Langmuir adsorption isotherm (R2: 0.9365), suggesting monolayer adsorption. At optimum operating condition, the energy and electrode consumption of 6.25 kWh/m3 and 0.87 kg/m3 were obtained, respectively. The findings provide the electrocoagulation-assisted adsorption mechanism for NO3 - removal, particularly in treating HWLL. This study provides a pathway for scientific research in HWLL treatment, bridging the gap between batch-scale experiments and potential field applications.

Treatment of complex compost leachate using a combined electrochemical and stripping process for safe surface water discharge

Electrochemical and bioelectrochemical technologies are increasingly explored to address the coupled challenges of wastewater treatment and energy sustainability.Among them, electrocoagulation (EC) and microbial fuel cells (MFCs) represent fundamentally different yet potentially complementary approaches.EC removes pollutants through the in situ generation of coagulants from sacrificial metal electrodes, enabling rapid treatment of suspended solids, emulsified oils, dyes, and many dissolved metals.In contrast, MFCs use electroactive microorganisms to oxidize biodegradable organics at the anode and transfer electrons to a cathode, allowing simultaneous wastewater treatment and direct electricity recovery.Although both technologies have been widely studied independently, integrated comparisons addressing treatment performance, energy balance, material constraints, and scale-up remain limited, especially for MFC systems using ionic-liquid (IL)-based membranes.This critical comparative review evaluates EC and IL-membrane-based MFCs in terms of pollutant removal efficiency, operational flexibility, energy consumption versus recovery, by-product generation, long-term stability, and techno-economic feasibility.Particular attention is given to supported ionic liquid membranes and polymer/ionic-liquid composite separators as promising materials for reducing internal resistance, while also considering membrane fouling, oxygen crossover, and IL leaching.Overall, EC is highly effective for rapid depollution but remains energy-and material-intensive, whereas MFC deployment depends on stable, low-resistance, and environmentally safe IL-based membranes.Hybrid EC-MFC systems appear especially promising for robust, scalable, and resource-efficient wastewater treatment.

Wastewater treatment by electrocoagulation (EC) using waste-derived electrodes is a promising solution, but its viability in irrigation reuse remains unclear. This work presents a quantitative framework integrating agrometeorological analysis (FAO-56 method) and waste information into energy and electrochemical models (Faraday's laws of dissolution) for viability assessment. The circular reuse framework was evaluated at a study site comprising a large institution surrounded by irrigated trees. Onsite experiments showed that electrochemical dosages as low as 20 g/m3 of aluminum (Al) scrap, or 60 g/m3 for iron (Fe) scrap, achieved significant removals (75%-94%) of COD, BOD, TSS, and turbidity. Onsite metal waste generation (593 kg/month) could accommodate ~98,000 m2 of surrounding irrigated lands. Crop production capacities of scrap metals (food per scrap) were estimated to reach 23.3 kg/kg using Al scrap. Based on crop water dynamics, theoretical fixed energy demand for renewable energy integration was calculated to be 0.58 kWh/m3. Validation of model components revealed that modeling scrap electrode consumption comprised minimal uncertainty compared with other components like crop water demand. The reuse framework shows promising potential as a WEFE nexus application but raised some socioeconomic concerns such as impacts on scrap scavengers' livelihoods. Prior to wider adoption, qualitative assessments are necessary to address heavy metals removal, soil contamination, nutrient content, and microbial indicators. Pilot-scale experiments are also encouraged to gain improved insights.

Naturally Occurring Radioactive Materials (NORMs) in industrial wastewater present significant environmental and public health challenges due to their persistence and radiotoxic effects. This comprehensive review analyzes 108 peer-reviewed publications from 2014 to 2025 on NORM treatment technologies for industrial wastewater. While previous reviews have focused on individual treatment methods or laboratory-scale studies, this work provides comparative performance analysis across multiple technologies under realistic industrial conditions, including high-salinity environments and competing ions. We emphasize membrane filtration, electrocoagulation (EC), ion exchange, and advanced oxidation processes, evaluating both their economic feasibility and environmental sustainability for practical industrial implementation. The review discusses the advantages and limitations of existing techniques, highlighting the need for integrated strategies that combine physical, chemical, and biological processes for enhanced remediation. Hybrid systems combining multiple technologies outperform individual approaches by 15-25% in removal efficiency. These advances are critical for ensuring safe water reuse and protecting water resources from radioactive contamination. Additionally, regulatory frameworks governing NORM management are examined, underscoring the importance of standardized disposal and treatment protocols. The review concludes by identifying research gaps and future directions. Priority areas include developing standardized treatment protocols and strengthening academia-industry collaboration to achieve scalable solutions aligned with UN Sustainable Development Goal 6.

ABSTRACT Electrocoagulation (EC) is a reliable technology for the treatment of industrial wastewaters with complex characteristics. It is, however, sensitive to many different factors including operating conditions, the dynamics of electrodes and the characteristics of the wastewater being treated. In addition, these factors are correlated; therefore, there is an increasing need for the development of AI‐based tools that can model non‐linear (NL) systems and provide a more accurate optimization process. In real life applications, sensitivity has been reported not only in the efficiency of EC treatment, but also in the energy required per unit of wastewater treated, as well as difficulties when scaling up EC systems from laboratory to industrial applications. This comprehensive study of the basic principles; key process parameters; and the key processes of reactors, electrodes; etc., and their limitations will provide an overview of how various types of artificial intelligence (AI) algorithms, including artificial neural networks (ANNs), adaptive neuro fuzzy inference systems (ANFISs), support vector machines (SVMs), and combinations thereof, can provide the necessary tools to predict, analyze and optimize the results of electrochemical processes. An assessment of how some of the main operational variables that can impact EC performance (e.g., pH, current density, electrode type and configuration, and length of treatment time) impacts the efficiency of pollutant removal, energy use, and electrode life, will also be included. These methods of analysis are able to accommodate complexity, multivariate nature and NL relationships of all the operational variables that have an impact on EC performance. Rather than a simple review of methods, this paper provides a holistic perspective that connects the mechanisms of electrochemical processes with current modelling trends being used to predict performance based on the use of data‐centric methods in conjunction with physicochemical theories.

The importance of this work lies in the application of a combined electrocoagulation/electro-Fenton (EC/EF) treatment for carwash wastewater, offering a cost-effective and efficient remediation approach. During electro-coagulation (EC), experiments were carried out in a cylindrical cell containing 450 mL of carwash wastewater. This process promotes the formation of $$Fe\left( {OH} \right)_{n}$$ (n = 2 or 3) as coagulants, along with $${\text{Fe}}^{3 + } {\text{/Fe}}^{2 + }$$ ions acting as catalysts. The effects of key operating parameters, including applied current, electrode material (Fe and Al), and initial pH, were evaluated, and both COD removal and energy consumption were assessed. In the EF stage, comparative trials were performed in stirred reactors equipped with a Pt anode and a carbon-felt cathode under O₂ bubbling to generate H₂O₂ at the cathode. The hydroxyl radicals produced at the anode surface through water oxidation and in the bulk solution via Fenton’s reagent (Fe2⁺/H₂O₂) promote the oxidative degradation of organic contaminants. The effects of the supporting electrolyte, applied current and the catalytic activity were investigated to optimize electro-Fenton efficiency. Under optimal EC conditions (I = 1 A, Fe electrode, pH = 5.7), 76.58% COD removal was achieved with an energy consumption of 0.987 kWh·m⁻3. Nearly complete COD removal (97.8%) was obtained using the combined process, where residual organics after EC were removed during electro-Fenton treatment at 0.3 A for 360 min.

Microplastics (MPs) are persistent emerging contaminants of global concern due to their potential ecological and human health risks. Sewage Treatment Plants (STPs) represent major pathways for MP discharge into aquatic environments, while conventional treatment processes are often insufficient for their complete removal, especially at small size ranges. In this study, influent and effluent samples were collected from an STP in Kafr Saad City, Damietta Governorate, Egypt, to evaluate the occurrence, characteristics, and removal efficiency of MPs. Identification was performed using visual inspection, stereomicroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and SEM–energy dispersive X-ray spectroscopy (SEM-EDX). Electrocoagulation (EC) was applied as a post-treatment using aluminum anodes and stainless-steel cathodes. The influent of STP contained 136 MPs/L, dominated by fibers (55.1%) and fragments (16.9%), while the effluent of STP after activated sludge treatment contained 23 MPs/L, corresponding to 83.1% removal. After EC treatment, MP concentrations decreased to 12 MPs/L in the influent and 2 MPs/L in the effluent, achieving over 91% removal. FTIR and SEM-EDX confirmed polyethylene and polypropylene as predominant polymers. The results highlight the limitations of conventional STPs and demonstrate EC as an effective post-treatment strategy for MP mitigation.

Efficient wastewater treatment is essential for environmental protection and sustainable water resource management, particularly when dealing with complex wastewater streams. Hybrid processes that combine electrochemical and physicochemical methods are increasingly explored due to their potential to enhance pollutant removal efficiency and reduce operating costs. This study evaluates the performance of hybrid treatment methods for complex compost wastewater by integrating electrocoagulation (EC), zeolite and magnetic assistance using aluminium (Al) and iron (Fe) electrodes. The influence of different electrode materials on magnetically assisted hybrid treatment process was assessed with respect to key treatment indicators, including chemical oxygen demand (COD) and turbidity reduction, as well as electrode mass loss, surface morphology, suspension settling, and EC sludge amount. Energy consumption and electrode usage were also considered to evaluate process economics. The results show that the application of a magnetic field in Al electrode systems slightly improves COD and turbidity removal, enhances anodic dissolution, and contributes to a more homogeneous surface morphology. In contrast, Fe electrodes exhibit a partially opposite response – the magnetic field accelerates floc settling and increases EC sludge production but reduces pollutant removal efficiency due to decreased dissolution intensity. Ferromagnetic Fe electrodes respond more strongly to the magnetic field, promoting aggregation and compaction of Fe-hydroxide flocs and partial surface stabilisation, which leads to lower anode mass. Weakly paramagnetic Al electrodes, on the other hand, are not directly affected by the magnetic field, but experience an indirect influence through magnetohydrodynamic (MHD)-induced micro-mixing and improved mass transfer. This leads to more uniform and intensive dissolution and a slightly higher pollutant removal efficiency. These findings provide a deeper understanding of the interactions between electrochemical and magnetic effects in hybrid electrocoagulation and offer guidance for optimising electrode material selection and magnetic field parameters to achieve more efficient and sustainable treatment of complex wastewater.

ABSTRACT Schematic representation and experimental overview of electrocoagulation (EC) treatment of distillery spentwash using aluminum electrodes (Al–Al plain, Al punched, and Al anodized). The setup includes a DC power supply connected to electrodes immersed in wastewater, showing the EC reactor during operation. Insets display electrode types, treated samples with visible color reduction, and sludge formation. Key operating parameters highlighted include voltage, electrode distance, electrolysis time, and anodization thickness. Electrochemical reactions at anode and cathode are illustrated. The graphical abstract emphasizes process optimization leading to high color and COD removal efficiency, with superior performance observed for anodized aluminum electrodes. Electrocoagulation (EC) is a wastewater treatment option, emphasizing its environmental friendliness, dense footprint, quick setup, and versatility. It looks at the key EC operational parameters and how they relate to conventional chemical coagulation, which are essential to comprehending the mechanism of pollutant removal. The study emphasizes the necessity of additional investigation to construct models for industrial-scale application and optimize process parameters. The distillery spentwash underwent a diagnostic description using standard analytical techniques, with treatment outcomes analyzed in terms of chemical oxygen demand (COD) and color removal efficiency. Various operational parameters, viz. voltage, electrode distance, electrolysis time, and anodization thickness, were investigated, and optimization was carried out using the response surface method. pH and stirring speed were maintained at constant levels of 7 and 500 rpm, respectively. The highest removal efficiencies were achieved under optimal conditions: 150-min electrolysis time, 25 V, electrode distance of 2 cm, and anodization thickness of 5 μm. Under these optimized conditions, the responses were estimated as follows 93.025% (color) and 89.896% (COD) removal efficiency in the Al-anodized electrode. Comparison among the three electrodes, namely Al -Al, Al punched, and Al anodized, indicated that the maximum pollutants removal was observed with the Al-anodized electrode.

Reverse osmosis is an advanced treatment technology, which shows high removal efficiencies for emerging pollutants; however, during the removal process, concentrate containing pollutants such as microplastics (MPs) is generated. Electro-coagulation (EC) offers lower chemical use, less sludge, and better removal efficiency when it comes to removing MPs. This study evaluated various EC conditions to optimize the removal of MP particles identified in the reverse osmosis wastewater exceeding 1,000 ea/L, with 14 types of MP polymers. Through EC batch experiments, the effects of inter-electrode distance, current density, and initial pH on turbidity and MPs removal were analyzed according to reaction time. Considering energy consumption as a priority, 95% removal rate of MPs was achieved under optimal conditions, which included an inter-electrode distance of 10 mm, a current density of 3 mA/cm2, and an initial pH of 5. Under these conditions, MPs were removed by flotation or sedimentation, depending on their density and size. Polypropylene, polyethylene, polystyrene, polymethyl methacrylate, polyurethane, polycarbonate, polyvinyl alcohol, and polyvinyl chloride were removed 100%, showing the best performance. This study suggests that EC treatment is an effective method for removing MPs and a promising treatment technology to alleviate the problem of MP pollution in wastewater treatment systems.

Arsenic-contaminated groundwater requires efficient, economically viable, and environmentally sustainable removal technologies. This review critically evaluates conventional treatment methods, including chemical coagulation/precipitation, adsorption, ion exchange, electrocoagulation (EC), and membrane filtration, alongside emerging approaches such as photocatalysis, magnetic nanomaterials, ozonation, bioremediation, and membrane distillation. A quantitative benchmarking of reported studies shows that membrane filtration, EC, and adsorption typically achieve 85–99% arsenic removal under optimized conditions, with energy consumption generally ranging from 0.2 to 4 kWh m–3, depending on process configuration. However, large-scale implementation is constrained by sludge and brine management, membrane fouling, electrode passivation, chemical demand, and associated operational costs. Emerging technologies demonstrate comparable removal efficiencies in laboratory-scale studies but face uncertainties regarding process stability, reaction kinetics, long-term performance, and techno-economic feasibility. Moreover, hybrid treatment systems have the potential to overcome the limitations of standalone processes, improve removal efficiency, and reduce environmental impacts, but require further lifecycle and cost assessments. By integrating performance metrics with environmental and economic trade-offs, this review identifies key scale-up challenges and outlines research priorities for sustainable arsenic mitigation.

Electrocoagulation (EC) process efficiency for treating synthetic petroleum refinery wastewater was investigated. The novelty of this study lies in the simultaneous removal of oil-in-water emulsion and calcium ions using an integrated experimental-statistical-financial approach, combining response surface methodology (RSM) optimization with COMSOL Multiphysics simulation. The impact of independent variables on the removal rates of both contaminants was studied and optimized using the central composite design method. Analysis of variance was employed to evaluate the significance of the variables and the mathematical model determined by RSM. The optimal conditions were determined to be a pH of 9, a current density of 6.123mA/cm2, an initial calcium concentration of 130ppm, an initial oil content concentration of 588ppm, a NaCl concentration of 2.5g/l, and a total electrolysis time of 98min. These conditions correspond to an oil content removal rate of 91.3% and a calcium removal rate of 72.9%. Energy consumption and total operation costs were calculated under these parameters to be 12 kWhm-3 and 10.32 EGPm-3, respectively. Fourier Transform Infrared spectroscopy, Energy-dispersive X-ray spectroscopy, and Scanning electron microscopy characterization were performed on the resulting sludge and scum at the optimum conditions and its utilization was discussed. Furthermore, COMSOL Multiphysics software was used to simulate the voltage distribution across the proposed cell to understand the electrochemical features. Overall, the statistical, financial, and simulated study demonstrates the feasibility of the EC technique for oil refinery wastewater treatment.