Development of electrocoagulation process for wastewater treatment: optimization by response surface methodology

Recent developments in conductive polysaccharide adsorbent formulations for environmental remediation: A review

Environmental remediation is crucial for human life and ecosystems, involving the cleanup of contaminated water to protect health and restore ecological balance. However, rapid industrialization and population growth have worsened pollution, particularly in water bodies, making effective wastewater treatment a key challenge in ensuring clean drinking water, and the adsorption of toxic gases for air treatment are the main strategies for environmental remediation. Among the various treatment methods, adsorption stands out for its high selectivity, low energy and chemical use, ease of operation, and cost-effectiveness. To date, innovative, highly efficient, non-toxic, engineered adsorbent materials have received potential interest from scientific and governmental communities. Conducting polymer-modified polysaccharide formulations are crucial in wastewater treatment due to their high surface area, adsorption efficiency, excellent stability, and eco-friendly, biodegradable properties. This review offers an extensive overview of recent progress in synthesizing conducting polymer-modified polysaccharide formulations (hydrogels, aerogels, nanofibers, and nanocomposites) for capturing toxic heavy metal ions, organic dyes, pharmaceuticals, phenols as well as adsorbing different toxic gases using various adsorption mechanisms. It also emphasizes the integration of different nanofillers, including carbon-based materials, Mxenes, nanoclay, metal/metal oxides, and hybrid nanomaterials, into conductive polysaccharide chains to improve their physicochemical properties and adsorption efficiency. The reported data showed that these engineered adsorbent materials based on conductive polysaccharide formulations have immense potential for wastewater treatment applications, offering more effective and sustainable solutions.

Electrocatalytic oxidation of hexafluoropropylene oxide homologues in water using a boron-doped diamond electrode

Hexafluoropropylene oxide (GenX) is a kind of substitute to PFOA, which has been listed in the Stockholm Convention. In this study, GenX was attempted to be degraded using a boron-doped diamond anode in the electrochemical oxidation system. The effects of operating parameters, including current density (0.5-10 mA/cm2), initial pH (3.0-11.49), initial concentration of GenX (20-150 mg/L), electrode distances (0.5-2 cm), electrolyte types (Na2SO4, NaCl, NaNO3 and NaHCO3) and Na2SO4 electrolyte concentration (40-80 mm), on GenX were studied. GenX can almost completely be degraded under the optimal operating parameters after 180 min of electrolysis. Free radical quenching experiments were carried out to investigate the effects of hydroxyl radicals and sulphate radicals on the degradation of GenX. The degradation intermediates were identified based on the ultra-high performance liquid chromatography equipped with a tandem mass spectrometer, and the degradation mechanisms were also proposed. Finally, the toxicities of GenX and its degradation products were evaluated using the QSAR models. The novelty is that the degradation mechanisms of the high concentration GenX (100 mg/L) were elucidated based on the free radical quenching experiments and the intermediates detected, when the degradation ratio reached 100%.

A solar-powered electrocoagulation process with a novel CNT/silver nanowire coated basalt fabric cathode for effective oil/water separation: From fundamentals to application

Electrocoagulation (EC) has proven its high efficiency and environmental sustainability for treating several types of wastewaters. However, the primary drawbacks of the conventional EC process are the suitable electrode materials and the relatively high cost due to the requirement for electric energy. To overcome these practical challenges, this study investigated effective oil/water separation by a solar-powered electrocoagulation (SPEC) process using a novel highly conductive basalt fabric (BF) cathode. The BF cathode was fabricated using a simple approach: dip-coating in carbon nanotubes (CNT) dispersion, followed by a bath exhaustion coating in a silver nanowires (AgNws) solution, and its successful preparation was confirmed through several advanced characterization techniques. The effect of the CNT-AgNws coating on the electrical conductivity of the BF-CNT/AgNws was investigated using the four-probe tester. The BF-CNT/AgNws cathode exhibited a high conductivity of 1.66 × 104 S/m, which indicates its applicability in the SPEC system. Under the operating conditions of applied voltage (25 V), SPEC time (30 min), stirring rate (150 rpm), and NaCl concentration (1 g/L), the experiment's results showed a high COD removal of 90.2 ± 0.03 %, a low energy consumption of 1.28 ± 0.01 kWh/kgCOD, and electrode consumption of 0.35 ± 0.06 kg/m3. In addition, due to the use of solar-powered energy, the overall cost was reduced by eliminating the electricity fees. Moreover, the reusability test results proved that the BF cathode has potential reusability in successive SPEC experiments while maintaining its performance. In conclusion, the obtained findings are very encouraging in designing novel EC cathodes for effective oily wastewater treatment at an industrial scale.

Electrochemical water treatment: Review of different approaches

The continued development in agriculture, the rapid growth of industrialization, and last but not least, the increase in the global population adversely affects the environment. The availability of drinking water decreases every year with the rise in water pollution, which is the consequence of the failure of conventional approaches to the water treatment process. This review will provide a comprehensive and detailed analysis of the electrochemical water treatment processes, as these techniques have several benefits over conventional methods, such as being cost-effective, easily applicable, selective, and broad applicability. This review starts by discussing the traditional methods. It explains their limitations and finishes the introductory part by presenting all the benefits of the electrochemical method over the conventional method for water treatment. Then, the discussion will be carried out on the individual electrochemical method with their detailed analysis of the selected approach, selected material, and optimized parameters for analysis. The elaborative study was targeted, and the different coupled systems, their analysis parameters, and derived removal efficiencies were given in tabular form. In the last section of the article, the conclusive statements present the prospects of the electrochemical method for water treatment.

Review on the impact of heavy metals from industrial wastewater effluent and removal technologies

The incidence of water pollution in developing countries is high due to the lack of regulatory policies and laws that protect water bodies from anthropogenic activities and industrial wastewater. Industrial wastewater contains significant amounts of heavy metals that are detrimental to human health, aquatic organisms, and the ecosystem. The focus of this review was to evaluate the sources and treatment methods of wastewater, with an emphasis on technologies, advantages, disadvantages, and innovation. It was observed that conventional methods of wastewater treatment (such as flotation, coagulation/flocculation, and adsorption) had shown promising results but posed certain limitations, such as the generation of high volumes of sludge, relatively low removal rates, inefficiency in treating low metal concentrations, and sensitivity to varying pH. Recent technologies like nanotechnology, photocatalysis, and electrochemical coagulation have significant advantages over conventional methods for removing heavy metals, including higher removal rates, improved energy efficiency, and greater selectivity for specific contaminants. However, the high costs associated with these advanced methods remain a major drawback. Therefore, we recommend that future developments in wastewater treatment technology focus on reducing both costs and waste generation.

Evaluation of enhanced chemical coagulation method for a case study on colloidal liquid particle in wastewater treatment: Statistical optimization analysis and implementation of machine learning

Coal mines are one of the largest sources of energy supply and generate significant volumes of wastewater. Chemical coagulation is one of the most effective methods for wastewater treatment. In this research, ferric and aluminum-based coagulants, along with polyacrylamide flocculants with positive, negative, and neutral charges, were utilized in chemical coagulation. After applying the Plackett-Burman screening method, it was found that ferric chloride coagulant, neutral flocculant, and slow mixing duration had the greatest impact. The chemical coagulation process was modeled and optimized by examining these factors using the Box-Behnken statistical design as input parameters and sedimentation velocity as the output. Under optimal conditions, the values for ferric chloride coagulant, neutral flocculant, mixing time in slow mode, and sedimentation velocity were determined to be 106.3 mg/L, 3.98 mg/L, 29.6 min, and 1.10 cm/min, respectively. Under optimal conditions, the removal percentages of pollutants, including TSS, turbidity, TDS, COD, and BOD, were obtained at 100%, 100%, 87%, 93%, and 81%, respectively. The experimental data were fitted using the BBD and ANN methods. Both models demonstrated very high agreement, but the ANN method performed better with an AAD% of 0.66, an MSE of 0.0001, and an R2 value of 0.99. All results were calculated with a confidence level above 98%, indicating that both models had very high reliability in modeling and prediction.

Optimization of the removal efficiency of three biodegradable chelating agents for soil cadmium

In recent years, there has been a significant increase in the release of cadmium-containing pollutants into the environment from mining, industrial emissions, wastewater irrigation and the use of chemical fertilizers and pesticides. This leads to the degradation of soil quality and poses a threat to human health. Chemical leaching remediation technology is an effective method for controlling Cd contamination in soil. However, the leaching agent has a low removal efficiency of heavy metals. In order to find more suitable environmentally friendly new leaching agents, this study investigates the effects of three biodegradable chelating agents PMAS, EDTMPS and GLDA on the removal of heavy metal Cd in soil in the single factor soil leaching experiment. The concentration of the chelating agents, the leaching time and the pH of the leaching solution were varied to study their effects. The Box-Behnken (BBD) effect based on RSM was used to design the experimental conditions to optimize the leaching process of three biodegradable chelating agents. The optimum conditions for Cd removal by PMAS, EDTMPS and GLDA were obtained as follows: concentration 7 %, pH = 3.61, reaction time 180 min; concentration 4.94 %, pH = 3.0, reaction time 180 min; and concentration 4.96 %, pH = 3.0, reaction time 180 min. The validation test results showed that the deviation from the experimental value is less than 3 % under the theoretically optimal washing conditions, confirming the reliability and accuracy of the response surface methodology optimization process, which provides a reference for the development of efficient, environmentally friendly and low-cost leaching agents.

Electro-galvanic alkalization and treatment of rainwater to obtain drinking water

Rainwater Electro-Galvanic Alkalization (EGA) was performed using copper and magnesium (1:1) electrode. Efficiently removal of pollutants without external energy consumption was carried out, in addition essential ions were dosed for alkalization of rainwater. The optimal system conditions were obtained using response surface methodology (RSM) by considering the following operating variables: flow rate and concentration of the supporting electrolyte (NaCl and CaCl2). Furthermore, the maximum efficiency of nitrate, ammoniacal nitrogen, colour, and turbidity removal was evaluated. The results showed that the response variables were mainly sensitive to the type of supporting electrolyte used and the flow rate. Under experimental conditions of 0.009 M (NaCl) and 20 mL min-1, the removal rate was 74.19%, 72.49%, and 81.43% for nitrates, colour, and turbidity, respectively, and the lowest concentration of ammoniacal nitrogen (0.99 mg L - 1 ) was obtained. The kinetic models for nitrate and colour were fitted to zero-order models with k = 0.33 mg L - 1 mi n - 1 and k = 0.933 Pt - Co , respectively. In addition, turbidity was fitted to a first-order model ( k = 0.1661 mi n - 1 ) , and ammoniacal nitrogen was fitted to a second-order model ( k = 0.0217 L m g - 1 mi n - 1 ) . The concentration increases of minerals such as Ca and Mg, which rises the rainwater alkalinity after treatment (pH shift from 6.1 to 8.91), was determined by inductively coupled plasma (ICP) analysis.

Comparative evaluation between Taguchi method and response surface method for optimization of electrocoagulation process in the context of treatment of dairy industry wastewater

The presence of a large amount of organic and inorganic pollutants in dairy effluent is a substantial environmental issue. This study investigated electrocoagulation (EC) as a potential treatment method for dairy wastewater under different operating conditions, such as applied voltage (5-25 V), electrolysis time (30-90 min), and inter-electrode distance (1-2 cm) by using aluminum electrodes. This study focuses on achieving the maximum removal of BOD, COD, and nitrate in dairy effluents with the aforementioned operating conditions. The process was optimized using the response surface methodology (RSM) and Taguchi method. RSM method optimized the electrocoagulation operating conditions such as the voltage at 23.75 V, time of 90 min, and inter-electrode distance at 1.07 cm. This optimization achieved the maximum removal percentage of BOD, COD, and nitrate at 79.06%, 84.35%, and 79.64%, respectively, in dairy effluent. Taguchi method optimized the electrocoagulation parameters such as the voltage at 25 V, time duration of 90 min, and inter-electrode distance of 1.00 cm, showcasing improved removal percentages of BOD, COD, and nitrate as 90.54%, 89.28%, and 82.74% respectively. The current study attempts to understand the optimization efficiencies between Taguchi method and response surface method for diary wastewater treatment.

Electrocoagulation in treatment of municipal wastewater- life cycle impact assessment

The purpose of this study is investigation of electrocoagulation (EC) as a treatment of municipal wastewater, integrating life cycle impact assessment (LCIA) for assessing its environmental performance of investigated treatment. The study evaluated the effectiveness of EC in removing physico-chemical and microbial parameters using aluminum (Al) and iron (Fe) electrodes in monopolar and bipolar modes. Bipolar arrangement of Al(-)/Al/Al/Al(+) electrodes achieved the highest removals: 70% COD, 72% BOD5 followed by complete elimination of total phosphorous, turbidity and microbial parameters. This treatment was subject to investigation of the influence of reaction time (t = 10-60 min) on removals at higher current density (CD = 3.33 mA/cm2). In order to reduce energy consumption, the same reaction time range was used with a reduced CD = 2.33 mA/cm2. Following removal efficiencies obtained: 47-72% COD (higher CD) and 53-78% (lower CD); 69-75% BOD5 (higher CD) and 55-74% CD (lower CD); 12-21% NH4- (higher CD) and 7-22% NH4- (lower CD). Total P, NO3- and NO2- compounds showed the same removals regardless the CD. Decrease in current density did not influence removals of total suspended matter, turbidity, salinity as well as microbial parameters. The bipolar arrangement of Al(-)/Al/Al/Al(+) electrodes, assuming a lower CD = 2.33 mA/cm2 and t = 30 min, was assessed with the Recipe 2016Midpoint (H) and USEtox v.2 LCIA methods to explore the environmental justification of using EC for wastewater treatment. The LCIA results revealed that the EC process significantly reduces water eutrophication and toxicity for freshwater and marine ecosystems, but has higher impacts in global warming, fossil fuel consumption, human toxicity, acidification, and terrestrial ecotoxicity due to high energy consumption. This can be mainly explained by the assumption in the study that the EC precipitate is dispersed to agricultural soil without any pre-treatment and material recovery, along with relatively high energy consumption during the process.

Coagulation process for the removal of color and turbidity from wet coffee processing industry wastewater using bio-coagulant: Optimization through central composite design

The growing problem of industrial pollution in developing countries, especially Ethiopia, has sparked serious issues about the quality of the water, particularly when it comes to the effluent from wet coffee processing industries. In response, this study investigates the potential of utilizing natural coagulants, Acanthus sennii C., Moringa stenopetala B., and Aloe vera L., either individually or in combination, for the treatment of coffee effluent. Methodologically, the study systematically varies operational parameters, including coagulant dose, pH levels, stirring speed, and stirring time, to evaluate their impact on coagulation efficiency. Experimental data undergo statistical analysis, employing ANOVA, while computational optimization techniques are employed using Design Expert software to determine optimal conditions. Notably, the blended form of the three coagulants emerges as particularly promising, yielding optimal conditions of 0.750 g/L coagulant dosage, pH 8.76, agitation speed of 80.73 rpm, and agitation time of 19.23 min. Under these optimized conditions, the blended coagulant achieves remarkable removal efficiencies, approximately 99.99% for color and 98.7% for turbidity. These findings underscore the efficiency of natural coagulants, particularly in blended form, for sustainable wastewater treatment in wet coffee processing.

Treatment and optimization of high-strength egg-wash wastewater effluent using electrocoagulation and electrooxidation methods

Egg-washing wastewater contains a high concentration of nutrition and organic matter since eggs are broken during the washing and cleaning processes. Moreover, the wastewater contains small amounts of detergents or sanitizing agents. These contaminants may pose environmental challenges when they are not properly managed or treated. The study scrutinizes the efficiency of electrocoagulation (EO) and electrooxidation (EO) approaches for egg-wash wastewater treatment. The response surface methodology was employed to optimize the operational parameters. The removal efficiencies of soluble chemical oxygen demand (sCOD 90%), ammonia (NH3-N 91%), nitrate (NO3--N 97%), nitrite (NO2--N 89.3%), total dissolved nitrogen (TDN 91%), and phosphate (90%) were measured under various treatment conditions. The optimum treatment conditions achieved in the combined EC + EO process were pH 6.0, current density 20 mA cm-2, and electrolysis time of 60 min, respectively. Degradation kinetics of the egg-wash pollutants showed a significant reduction in half-life (t1/2) with EO (after EC-Aluminum) at 15 min, 12 min, 17 min, and 15 min for sCOD, NO2--N. NO3--N, and TDN, respectively. Whereas the half-life of NH3-N (18 min) and phosphate (17 min) reduced significantly with the EO (after EC-iron). Al and Fe electrodes coupled with boron-doped diamond were found efficient for pollutant removal. Environmental implication. Egg-wash wastewater has a high protein content and contains nutrients that are essential for living organisms. While these compounds can be valuable for agricultural use by increasing soil phosphate concentration, they can also become an issue if the excess nutrients are not properly managed. The soil has a threshold limit for holding phosphate, and any excess amount may be transported through surface runoff or contaminate groundwater through leachate, potentially affecting aquatic ecosystems and water quality. This study explores the efficiency of electrocoagulation and electrooxidation methods in treating egg-wash wastewater. These methods aim to remove pollutants and reduce their environmental impact.

Recent advances on the methods developed for the identification and detection of emerging contaminant microplastics: a review

The widespread use of plastics, popular for their versatility and cost-efficiency in mass production, has led to their essential role in modern society. Their remarkable attributes, such as flexibility, mechanical strength, lightweight, and affordability, have further strengthened their importance. However, the emergence of microplastics (MPs), minute plastic particles, has raised environmental concerns. Over the last decade, numerous studies have uncovered MPs of varying sizes in diverse environments. They primarily originate from textile fibres and cosmetic products, with large plastic items undergoing degradation and contributing as secondary sources. The bioaccumulation of MPs, with potential ingestion by humans through the food chain, underscores their significance as environmental contaminants. Therefore, continuous monitoring of environmental and food samples is imperative. A range of spectroscopic techniques, including vibrational spectroscopy, Raman spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, hyperspectral imaging, and nuclear magnetic resonance (NMR) spectroscopy, facilitates the detection of MPs. This review offers a comprehensive overview of the analytical methods employed for sample collection, characterization, and analysis of MPs. It also emphasizes the crucial criteria for selecting practical and standardized techniques for the detection of MPs. Despite advancements, challenges persist in this field, and this review suggests potential strategies to address these limitations. The development of effective protocols for the accurate identification and quantification of MPs in real-world samples is of paramount importance. This review further highlights the accumulation of microplastics in various edible species, such as crabs, pelagic fish, finfish, shellfish, American oysters, and mussels, shedding light on the extreme implications of MPs on our food chain.

Response surface optimization of chemical coagulation for solid-liquid separation of dairy manure slurry through Box-Behnken design with desirability function

Discharging livestock manure slurry without proper treatment causes various environmental and sociological problems. Chemical coagulation is a widely used and easily applicable method for treating such wastewater. However, the technique requires optimization to enhance coagulation efficiency while minimizing chemical usage. In this study, we propose an efficient, low-cost, and environmentally safe chemical coagulation method for solid-liquid separation of dairy manure slurry. Experiments were conducted in laboratory jar tests using dairy manure slurry to investigate the impact of coagulants, specifically polyaluminum chloride (PAC) and cationic polyacrylamide (CPAM), as well as pH, on the process of solid-liquid separation. Preliminary ranges of PAC, CPAM, and pH were estimated through single-factor experiments. Coagulation optimization and modeling were performed using the response surface methodology (RSM) with the Box-Behnken design (BBD), wherein the desired goal of each parameter was set to maximize solid-liquid separation efficiency while reducing chemical dosage to maintain residual aluminum (Al) concentrations below water quality standards. Numerical optimization predicted that the optimal dosages were 75 mg/L of PAC and 35 mg/L of CPAM at pH 7. Under these conditions, removal efficiencies of 99% for turbidity and 97% for chemical oxygen demand (COD) were achieved, with a minimal residual Al concentration of 0.045 mg/L. Positive zeta potential values in the treated water confirmed complete separation of negatively charged solids in the dairy manure slurry. The response values predicted by BBD aligned with the experimental results, and the analysis of variance (ANOVA) demonstrated the predictability and accuracy of the response models. Consequently, this study highlights the practical application of RSM with BBD in optimizing chemical coagulation using PAC and CPAM to achieve efficient solid-liquid separation in livestock wastewater while maintaining low residual Al concentrations.

Electrochemical Characterization Using Biosensors with the Coagulant Moringa oleifera Seed Lectin (cMoL)

Triturated Moringa oleifera seeds have components that adsorb recalcitrant indigo carmine dye. Coagulating proteins known as lectins (carbohydrate-binding proteins) have already been purified from the powder of these seeds, in milligram amounts. The coagulant lectin from M. oleifera seeds (cMoL) was characterized by potentiometry and scanning electron microscopy (SEM) using MOFs, or metal-organic frameworks, of [Cu₃(BTC)₂(H₂O)₃]_n to immobilize cMoL and construct biosensors. The potentiometric biosensor revealed an increase in the electrochemical potential resulting from the Pt/MOF/cMoL interaction with different concentrations of galactose in the electrolytic medium. The developed aluminum batteries constructed with recycled cans degraded an indigo carmine dye solution; the oxide reduction reactions of the batteries generated Al(OH)₃, promoting dye electrocoagulation. Biosensors were used to investigate cMoL interactions with a specific galactose concentration and monitored residual dye. SEM revealed the components of the electrode assembly steps. Cyclic voltammetry showed differentiated redox peaks related to dye residue quantification by cMoL. Electrochemical systems were used to evaluate cMoL interactions with galactose ligands and efficiently degraded dye. Biosensors could be used for lectin characterization and monitoring dye residues in environmental effluents of the textile industry.

Cadmium removal from aqueous solution by blended bamboo sawdust/rice-husk biochar; optimization of influencing parameters

This study attempted to investigate the adsorptive potential of blended bamboo (Oxytenanthera abyssinica) sawdust/rice husk (BSD/RH) at a ratio of 1:1 carbonized at 400 °C for the sorption of cadmium ions from synthetic solutions in batch mode. The Box-Behnken Design in response surface methodology (RSM) was used to achieve the best removal efficiency and adsorption capacity of the biochar. With a p-value of 0.0001, the initial Cd2+ concentration and adsorbent dose were discovered to be the most significant parameters controlling the adsorption capacity and removal efficiency of Cd2+ from the solution. At a pH of 8.95, ionic strength of 0.020 mol/L KNO3, a contact time of 15 min, an initial concentration of 200 mg/L, and an adsorbent dose of 0.5 g, the optimum Cd2+ removal and adsorption capacity of 99.97% and 358.65 mg/g, respectively, were obtained. The optimized conditions were later used to determine the removal efficiency and adsorption capacity of pristine biochars of rice husk and bamboo sawdust, which were found to be 79.8% and 83.7%, respectively. This finding indicates the potential for using biosorbent derived from blended feedstock materials to remove heavy metals such as cadmium.

Electrocoagulation removal of Pb, Cd, and Cu ions from wastewater using a new configuration of electrodes

A new configuration of aluminum electrodes has been performed in an electrocoagulation reactor (ECR) to remove toxic metals from synthetic wastewater. The ECR contains four concentric-cubic electrodes that were connected to the DC power supply with a bipolar mode. The ability of this reactor to eliminate 200 ppm Pb, 200 ppm Cd and 200 ppm Cu from wastewater was investigated under the effect of pH (4-10), applied current (0.2-2.6 A), and the reaction time of (4-60 min). Two grams of NaCl were added to each experiment to enhance the electrical conductivity and minimize the passivation of cathode surfaces. The experiments, analysis, and optimization were conducted using response surface methodology type Box-Behnken design (RSM-BBD) and the Minitab-statistical software program. The highest elimination of heavy metals was: Pb-99.73%, Cd-98.54%, and Cu-98.92% at pH 10, 1.4 A of the applied current, and 60 min of the reaction time. The total real consumption of anodes under these conditions was 0.55 g, and the energy consumption was 12.71 kWh/m3. All reactions of metal removal that occurred in the present EC reactor obey the kinetic of a first-order reaction. Thermodynamics parameters of present electrocoagulation removal of heavy metals indicate an endothermic, spontaneous nature, and random irregularity at the liquid-solid interaction. The highest values of removal efficiencies and the considerably lowest values of energy and electrode consumption proved that the electrocoagulation technology applies in wastewater treatment containing toxic metals.•The anode electrodes were perforated to decrease the amount of electrode consumption, while the cathode electrodes were not perforated.•The new EC reactor eliminated Pb-99.73%, Cd-98.54%, and Cu-98.92% of 200 mg/l of each metal at pH 10, applied current of 1.4 A, and reaction time of 60 min. Moreover, the consumption of energy and electrodes was significantly low.•The performance indicator (R²) of the studied responses was higher than 0.95.

A Review of Hybrid Process Development Based on Electrochemical and Advanced Oxidation Processes for the Treatment of Industrial Wastewater

Nowadays, increased human activity, industrialization, and urbanization result in the production of enormous quantities of wastewater. Generally, physicochemical and biological methods are employed to treat industrial effluent and wastewater and have demonstrated high efficacy in removing pollutants. However, some industrial effluent and wastewater contain contaminants that are extremely difficult to remove using standard physicochemical and biological processes. Previously, electrochemical and hybrid advanced oxidation processes (AOP) were considered a viable and promising alternative for achieving an adequate effluent treatment strategy in such instances. These processes rely on the production of hydroxyl radicals, which are highly reactive oxidants that efficiently break down contaminants found in wastewater and industrial effluent. This review focuses on the removal of contaminants from industrial effluents and wastewater through the integration of electrochemical and advanced oxidation techniques. These processes include electrooxidation, electrocoagulation/electroflocculation, electroflotation, photo-Fenton, ozone-photo-Fenton, sono-photo-Fenton, photo-electro-Fenton, ozone/electrocoagulation, sono-electrocoagulation, and peroxi/photo/electrocoagulation. The data acquired from over 150 published articles, most of which were laboratory experiments, demonstrated that the hybrid process is more effective in removing contaminants from industrial effluent and wastewater than standalone processes.