Electrokinetic Remediation Process Research Articles

Study of the Removal Efficiency of Chromium Ions Using a Membrane by Electro-Kinetic Technique from Sludge.

Recently, electro-kinetic (EK) remediation has become more popular as a novel method for removing chromium contamination from soil. This approach, however, is ineffective since it uses both cationic and anionic forms of chromium. In this study, a membrane-based technique was employed to increase the efficiency of the electro-kinetic removal of chromium. Chromium removal from polluted sludge was studied using four bench-scale experiments. Two of these experiments employed distilled water (EK-1 and EK-2 and membrane), whereas the other used acetic acid as the catholyte (EK-3 and EK-4 and membrane). The pH, total chromium, and fractionation of chromium in the sludge were measured after remediation. In the EK-1, EK-2 and membrane, and EK-3 and EK-4 and membrane trials, the average removal efficiencies of total chromium were 47.6%, 58.6%, and 74.4%, 79.6%, respectively. In contrast to the electro-kinetic remediation strategy, which left approximately 80% of the sludge neutral or alkaline after treatment, the membrane created acidic soil conditions throughout the sludge. For example, the high field intensity used in the membrane tests may have helped to facilitate chromium desorption, dissolution, and separation from the sludge and enhanced chromium mobility. The findings show that the membrane can improve the effectiveness of chromium removal from sludge when utilized in the EK remediation process.

The Influence of Electrokinetic Remediation Process on the Removal of Cationic and Anionic Dyes from Kaolinitic Soils

Low permeability soils possess specific mineralogical properties such as particle size, high buffer capacity, and high sorption capacity, which make them difficult to remediate and so pose serious environmental problems when polluted. The grain pores of these low permeability so ils trap in pollutants tightly, which are inaccessible and non-responsive to traditional technologies during remediation. Traditional technologies, some of which are ex-situ remediation techniques further compound these environmental problems through logistics and economic infeasibility. Electrokinetic Remediation (EKR) can offer certain advantages for treatment of various contaminants which include organic compounds, heavy metals, radionuclides, organic waste and some mixed inorganic species from a matrix with high salinity, low permeability and high buffering capacity. In addition, (EKR) is a clean and novel technique which accesses the grain pores of low permeability soils such as clays and silts, which have proven non-responsive to other soil remediation technologies such as soil flushing and soil washing. Among these fine soils, it has been proven that (EKR) is more effective on clay soil with particle size <2mm, moderate plasticity, lower cation exchange capacity (CEC) and lower buffering capacity which can be found in this order: kaolinite>illinite >bentonite.

Cork barriers for the remediation of soils polluted with lindane

The in-situ removal of lindane from spiked soil was studied using cork barriers combined with electrokinetic and ohmic heating soil remediation processes. Both vertical and horizontal cork barriers have been evaluated to retain pollutants mobilized by electro-osmotic flow or volatilized by ohmic heating. Moreover, the addition of surfactant solutions in electrolyte wells has been evaluated to promote the dragging of lindane by electrokinetic fluxes. Results indicated that the drag of lindane by liquid flows is not as important as expected, opposite to what happened with the dragging by gaseous flows. The retention of gaseous lindane was also confirmed in adsorption tests carried out in a column packed with cork granules. The addition of surfactant had a very limited effect on the mobility of lindane, and dragging of this species to the electrode wells or to a permeable reactive barrier. On the contrary, the reactivity of lindane during the electrochemical treatments is relevant due to the electrokinetic basic front promoting the in-situ conversion of lindane into less chlorinated pollutants.

Application of novel polypyrrole/melamine foam auxiliary electrode in promoting electrokinetic remediation of Cr(VI)-contaminated soil

There is an urgent need for an effective remediation method for soil that has been heavily polluted by heavy metals. The application of polypyrrole/melamine foam (PPy-MF) auxiliary electrode in the traditional electrokinetic remediation (EKR) system greatly increased the removal efficiency of Cr(VI) by enhancing electrical conductivity in soil, current strength of the system, and optimized the distribution of the electric field. Because of the strong Lewis acid property of PPy, it can inhibit the development of an alkali front in the EKR process in addition to buffering the polarization of the catholyte's pH. Application of PPy-MF auxiliary electrode increased the removal rates of both total Cr and Cr(VI) by 34.5 % and 11.5 %, 26.1 % and 10.1 %, and 25.2 % and 9.9 % at 30 V, 45 V, and 60 V voltage conditions, respectively, compared with traditional EKR, and improved the overall soil Cr(VI) reduction rate. Additionally, due to the effective Cr(VI) adsorption reduction of PPy-MF, the total Cr concentration in the anolyte was significantly decreased. This study provides a facile and effective way in remediation of Cr(VI)-contaminated soils.

Theoretical determination of zeta potential for the variable charge soil considering the pH variation based on the Stern-Gouy double-layer model

Electrokinetic remediation (EKR) is a promising alternative for the contaminated soil with low hydraulic permeability. The nonlinearity of the electroosmotic flow (EOF) is mainly induced by the nonuniform variation of the pH and thus the zeta potential of the soil during the EKR process. The empirical relation between the zeta potential and the pH for kaolinite is currently applied to analyze the nonlinearity of the EOF. A new perspective for theoretical determination of the zeta potential for the variable charge soil is proposed in this study. The prediction model incorporates the pH, the valence and concentration of the electrolyte, and the temperature and permittivity of the solvent surrounding the clay particles. Satisfying agreement between the calculated and measured curves of zeta potential versus pH for three types of variable charge soil was achieved. This model would act as a useful tool to simulate the nonlinearity of the electroosmosis of the variable charge soil and provide guidance and precise control mechanism for maximizing the efficiency of the EOF.

Monitoring the efficiency of electro-kinetic soil remediation process with geophysical surveying method

Geoelectric surveying is a useful method of non-invasive investigation (e.g.: for the purpose of space delineation or time dependant monitoring) of subsurface contaminants. The measured onsite electrical resistivity values are a function of certain soil parameters and the electric properties of the contaminant. With executing time domain field surveys before and after the remediation process its efficiency on contamination removal can be valorized.In this study we present a field case to illustrate the applicability of the geoelectric method for monitoring the efficiency of hydrocarbon removal and highlighting the problems of interpretation due to change of soil parameters and various hydrocarbon composition. Due to the side effects of electro-kinetic soil remediation process some soil parameters affecting the electrical resistivity are also changed. Therefore, when interpreting the data the of field survey one must be able to separate the geoelectric response of the remnant contamination from the changed soil parameters. The paper presents a multilevel interpretation method when the measured electrical resistivity data were correlated with the time-domain results of detailed soil sample analytics including particle size distribution, physical properties, and chemical composition. As a result we were able to separate the time domain geoelectric effects of the soil from the geoelectric response of the hydrocarbon contamination and we could correlate the electrical resistivity anomalies with the integrated effects of hydrocarbon content and changes in the soil due to the remediation treatment.

Ecological assessment of different electrokinetic remediation strategies: a pilot scale study

The electrokinetic remediation method can function as a primary or secondary technology and can be applied in conjunction with other physical and biological methods, such as soil washing, phytoremediation, and bioremediation. Environmental impacts arising from the electrokinetic remediation process can be determined using life cycle assessment analysis (LCA) or other tools. This study compared the conventional electrokinetic remediation strategy with two hybrid strategies: electrokinetic-phytoremediation (EKR-Phyto) and electrokinetic-bioremediation (EKR-Bio). The environmental performance of the three strategies is then tested through LCA analysis. The database used was The Ecoinvent, and the freeware software used during the inventory stage was OpenLCA. The impact assessment stage was used in the Recipe I (2016) midpoints, Available Water Remaining (AWARE) midpoint, Intergovernmental Panel Climate Change (IPCC) midpoint (2003), UNEP Society of Environmental Toxicology (USEtox) midpoint, and cumulative energy demand midpoint. The significance of the analysis results was not obtained for the GWP parameter but for the freshwater eutrophication parameter. Among the three strategies, the EKR-Phyto strategy showed the highest significance in eutrophication but the lowest significance in land change. Substitution of chemical fertilizers into natural fertilizers in the EKR-Phyto strategy can be an opportunity for environmental sustainability. The highest impact for ecological analysis of the three strategies was EKR-Phyto in terms of GWP, the sum of primary energy, Acidification Potential (AP), and Photochemical Ozone Creation Potential (POCP).

Surfactant combined with PASP enhance electrokinetic remediation removal heavy metal and hydrocarbon from contaminated soil

ABSTRACT In this work, a new electrokinetic remediation technology was used to remove heavy metal and hydrocarbon from contaminated soil. The surfactant combined with PASP (Polyaspartic acid) was used to enhance heavy metal and hydrocarbon removing from contaminated soil. Electric current, soil pH, electroosmotic flow, water content variation, heavy metal removal efficiency and residual content distribution, heavy metal speciation, removal of TPH (total petroleum hydrocarbons), group composition of oil, mechanism of enhance electrokinetic remediation were investigated during the electrokinetic remediation process. Results indicated that Rhamnolipid, PASP, Tween 80 and SDS (sodium dodecyl sulphate) can reduce the heavy metal precipitation during the electrokinetic remediation process. Also, it can promote EOF (electroosmotic flow) and electrolyte evaporation during the EK remediation. The rhamnolipid (3.0 g.L−1) combined with PASP (3.0 g.L−1) can significantly improve Cu, Cr, Ni, Pb and hydrocarbon mobility and solubility during the EK remediations. Cu, Cr, Ni and Pb obtained the dominant removal efficiencies, which were 66.0 ± 3.45%, 61.2 ± 4.35%, 67.1 ± 3.21%, 61.8 ± 4.22%, respectively. Also, the TPH has attained a dominant removal efficiency of 80.2 ± 4.36% after the enhanced electrokinetic remediation. This research provides a novel in-situ remediation approach for reducing heavy metals and hydrocarbon from contaminated soil in an environmentally friendly way.

Process-based pore-scale simulation of electrokinetic remediation of organic pollutant in porous media

Electrokinetic remediation (EKR) is a promising remediation technology for low-permeability porous media contaminated with organic pollutants. To reveal the processes of nonlinear electroosmotic flow (EOF) and to elucidate the key factors controlling the efficiency of EKR, a process-based pore-scale numerical model was established. Nernst-Planck-Poisson Equation is coupled with Navier-Stokes Equation to describe the transport of species. 1-pK model is applied to evaluate time-varying zeta potential during EKR process. Totally 33 cases are simulated, which include the settings of 3 background concentrations (Cb) of ions in media, 3 pK values, 3 enhanced factor (d, corresponding to reciprocal of diameter of electrode well) values, and two different initial conditions. It is found that all of Cb, pK and d impact EOF and the removal efficiency of organic species. From this study, media with pK of 3.5 and 8.5 are more suitable for EKR with about 5–10 times faster remove rate than media with pK of 5.5. Nonlinear EOF, including decreasing EOF rate and reverse EOF, is more likely to occur in cases with pK of 5.5 and higher values of Cb and d, which can reduce efficiency of EKR by 2–4 times. Using an electrolyte with ion concentration closer to the original background concentrations of ions in soil can favour better removal efficiency.

Enhanced electrokinetic remediation of heterogeneous aquifer co-contaminated with Cr(VI) and nitrate by rhamnolipids

Electrokinetic remediation is an in situ remediation technique that is gaining increasing attention in the field of groundwater contaminant removal. Aquifers co-contaminated with hexavalent chromium (Cr(VI)) and nitrate are becoming more common and research on the remediation of this pollutant is attracting worldwide attention owing to the considerable human health hazards of Cr(VI) and nitrate, including carcinogenicity, genotoxicity, and cytotoxicity. Electrokinetic remediation technology has significant advantages for the treatment of heterogeneous aquifers. This is the first study on the electrokinetic remediation of an aquifer co-contaminated with toxic heavy metals and inorganic salts. This study investigated the feasibility of electrokinetic remediation for layered heterogeneous aquifers co-contaminated with Cr(VI) and nitrate in the presence of groundwater flow, and it also assessed the ability of the anionic biosurfactant rhamnolipid to enhance the remediation effect. Changes in the pH, electrical conductivity, Cr(VI), nitrate, electric current, and the distribution of energy consumption and the voltage contour were analyzed through seven sets of experiments. The highest removal rates of Cr(VI) and nitrate were 97.30% and 87.08%, respectively. Rhamnolipids greatly enhanced the electrokinetic remediation process, especially in medium with moderately low permeability: 1) rhamnolipids improved Cr(VI) removal(from 1.62% of EK3 to 85.57% of EK6 and from 48.42% of EK4 to 94.18% of EK7) through migration and reduction; and 2) rhamnolipids improved nitrate removal (from 13.03% of EK3 to 71.72% of EK6 and from 23.69% of EK4 to 78.43% of EK7) through enhanced migration.

Enhancement of the electrokinetic removal of heavy metals, cations, anions, and other elements from soil by integrating PCPSS and a chelating agent

BackgroundRecently, we have developed a new soil electrokinetic remediation (SEKR) process, hereinafter referred to as the perforated cathode pipe SEKR system (PCPSS), to achieve remediation intensification. Some obstacles, such as the low removal of some heavy metals, particularly Ni, limited our previous PCPCS. MethodsWe aim to improve the removal efficiency of the PCPSS by adding a chelating agent (i.e., ethylenediaminetetraacetic acid (EDTA)). Given the unsatisfactory remediation results obtained in our previous studies, the Taguchi approach (L9OA) was exploited in this work as an experimental design to determine the optimal level of factors that could enhance Ni removal. Significant findingsResults showed that an electric potential of 3 V, addition of 0.5 mol of EDTA, and an initial Ni concentration in the range of 10–20 mg kg−1 could optimize Ni removal. Confirmation experiments conducted on natural contaminated soil showed the following order of removal of heavy metals and other elements: Al (70%) > Co (69%) > Fe (63.5%) > Cu (55%) > Mn (52.8%) > Zn (43.17%) > Cr (41.41%) > Ni (22.26%). Among the studied soil cations, Mg showed the best removal rate, Ba showed moderate removal rate, and Ca showed the lowest removal rate. Notably, the removal rate of V was much higher than that of born (B).

Environmental Footprint Analysis Tools of Electrokinetic Remediation (EKR): A Bibliometric View of The Literature

Electrokinetic remediation (EKR) technology has been applied in both lab and pilot scales to actual size since 1993. Recently, sustainable measures for EKR have been relatively considered a form of minimizing resource use during land restoration. This study aims to identify the environmental footprint assessment tools that arise during the EKR process according to the scale of the application. 284 scientific literature indexed by Scopus and the Web of Science during 2011-2021 was analyzed using the Systematic Literature Review (SLR) method, and the results were visualized using the VOSviewer application. The investigated parameters included the amount of scientific literature, year of publication, topics of scientific literature, authors of literature and their country of origin, names of reputable journals, and a number of citations. Research results from 43 scientific literature studies show that different environmental footprint analyses in EKR have been applied in various parts of the world. Most of environmental footprint assessment tools used by researchers include life cycle assessment (LCA) and green and sustainable remediation (GSR) tools. A recommendation is given to the GSR tools developed by the US EPA because known to have the simplest analytical method compared to other methods.

Preliminary Study of the Influence of Supplementary Cementitious Materials on the Application of Electro Remediation Processes.

Supplementary cementitious materials (SCMs), based on pozzolanic materials, improve durability against corrosion and mechanical properties of concrete structures by decreasing their permeability. Even though the influence of SCMs on the chloride combination with the cement phases has been widely studied, its effects on electrokinetic remediation processes such as electrochemical chloride extraction (ECE) have not been clarified. For this reason, the influences of two SCMs, fly ash (FA) and blast-furnace slag, on the extraction of chloride through the concrete net pore have been studied in this paper to determine the viability of the application of electrochemical chloride treatments in these structural materials. Alternative electrochemical indicators to the ones included in the standards are also proposed to better determine the final point of the treatment. A cement replacement of 8% on both SCM (FA and slag) has been tested, and in addition to charge density, chloride content, and corrosion measurement at the end of the treatment (included in the standards), different electrical and electrochemical indicators such as electrical resistivity, EIS, or depolarized potentials are used to monitor the ECE. The influence of the treatment on disconnected steel has been also studied. In the case of slag mortar, no steel passivation was reached, while in the case of FA, the passivation of the steels connected to treatment was reached in the same way as in plain CEM I specimens. A degree of protection is also detected in the nonconnected steel, which means that substitution of 8% in FA does not affect treatment efficiency and can also partially protect the metallic elements embedded in the same electrolyte but not connected to the treatment.

Mechanism of bio-electrokinetic remediation of pyrene contaminated soil: Effects of an electric field on the degradation pathway and microbial metabolic processes

In this study, the mechanism of bio-electrokinetic (BIO-EK) remediation to improve the degradation of pyrene was evaluated based on an analysis of the intermediate products and the microbial community. The results show that BIO-EK remediation has a higher pyrene degradation efficiency on pyrene and its intermediate products than the bioremediation and electrokinetic (EK) remediation processes. A series of intermediate products were detected. According to the type of the intermediate products, two degradation pathways, biological metabolism and electrochemical oxidation, are proposed in the BIO-EK remediation of pyrene. Furthermore, the primary microbial taxa involved in the pollutant degradation changed, which led to variations in the functional gene components. The abundant and functional genes related to metabolism were specifically analyzed. The results indicate that the electric field promotes the expression of metabolisms associated with 14 carbohydrates, 13 lipids, 13 amino acids, five energies, and in particular, 11 xenobiotics. These results suggest that in addition to the promotion effect on the microbial metabolism caused by the electric field, BIO-EK remediation can promote the degradation of pollutants due to the coexistence of a microbial metabolic pathway and an electrochemical oxidation pathway.

Influence of polarity exchange frequency on electrokinetic remediation of Cr-contaminated soil using DC and solar energy

Electrokinetic remediation (EKR) is a remediation method that can effectively remove heavy metals from soil. Traditional EKR uses an external power source to consume electrical energy, in the present study, through the experiment of different electrode exchange frequency to remediate Cr contaminated soil, the effect of polarity exchange electric remediation and the influencing factors of Cr(VI) to Cr(III) conversion are discussed. Five experiments were conducted using DC power supply with conventional EKR (T1), DC power supply with polarity exchange EKR (T2, T3) and solar energy with EKR (T4, T5). The results showed that the T1 experiment had the maximum removal rate of total Cr (42.03 %) and Cr(VI) (85.50 %) but had an adverse effect on soil pH. T2, which exchanged polarity every 24 h, and T3, which exchanged polarity after 84 h, had smaller adverse effects on soil pH, but the removal efficiency was reduced due to repeated migration. The reduction of Cr(VI) to Cr(III) occurred during the EKR processes, the content of Cr(III) increased greatly. Furthermore, few differences were observed between DC power and solar power on the EKR experiments. Therefore, the combination of electrokinetics and solar energy is a feasible method for Cr-contaminated soil.

Numerical Implementation of Electrokinetics for Removal of Heavy Metals from Granite Waste

The goal of the study is to incorporate the electrokinetic models and estimate the remediation time for maximum removal of heavy metals (HMs) from polluted soils. Most of the conventional electrokinetic technologies have not considered the electrokinetic models in the removal of HMs from polluted soils. We addressed this problem and incorporated the electrokinetics and applied for experimental Electrokinetic Soil Remediation (EKSR) process particularly, to extract the numerical data between removal performance of HMs versus remediation time with help of the MATLAB program. In the experimental study, chelating chemical agents (citric acid and ethylenediaminetetraacetic acid (EDTA)) were used in EKSR process under constant voltage gradient (2V/cm) for the removal of Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn) and Manganese (Mn) ions from granite dump soil. We experimentally investigated that the removal performance of HMs in chelating agents enhanced EKSR were about 6 to7 times more than when unenhanced in 20 days of treatment. Furthermore, we estimated the remediation time about 52 to 54 days for complete removal of HMs using electrokinetic models. The study may be useful for the researcher’s particularly, in the soil decontamination studies to overcome the uncertainty in the process optimization and scale-up the process to the pilot plant and field level.

Experimental and Numerical studies on remediation of mixed metal-contaminated sediments by electrokinetics focusing on fractionation changes.

Electrokinetic remediation technique is widely applied for the removal of heavy metal from contaminated soil, but the soil buffering capacity and fractionation of heavy metals mainly affect the cost and duration of the treatment. This study aims to treat heavy metal-contaminated sediments by electrokinetic remediation (EKR) technique by using various enhancing agents such as EDTA, [Formula: see text], HCI, [Formula: see text], acetic acid and citric acid for optimizing the cost and treatment duration. The optimum molar concentration of enhancing agent for treatment was estimated by batch experiments to maximize the dissolution of target heavy metals and reduce the dissolution of earth metals (Fe, Al and Ca) to maintain soil health. The EKR experiments were performed up to 15 days with the above enhancing agents to reduce the risk associated with heavy metals and the selection of enhancing agents based on removal efficiency was found to be in an order of EDTA > citric acid > acetic acid > [Formula: see text] > HCl [Formula: see text] [Formula: see text]. Also, a numerical model has been developed by incorporating main electrokinetic transport phenomena (electromigration and electroosmosis) and geochemical processes for the prediction of treatment duration and to scale up the EKR process. The model predicts well with experimental heavy metal removal with a MAPD of [Formula: see text] 2-18 %. The parametric study on electrode distance for full-scale EKR treatment was found in this study as [Formula: see text] 0.5 m.

Electrokinetic remediation of copper polluted soil concatenated with an adsorption zone

Copper is one among the toxic premature metals found in the Stone Age, which can lead to a variety of contamination problems. Being the top moving metal in the metal industry, contamination due to copper is also increasing. The pollution is not only contended with water, it also extends to contamination of land. Electrokinetic remediation is an effective method for removing copper from the soil. The experiment when performed with tap water as anolyte and catholyte resulted only with a poor efficiency of 29.33 %. The removal efficiency popped up to 35.10 % with addition of 0.1 M Ammonium acetate as anolyte. Still to further increase its efficiency Ammonia-acid is used in the process which enhanced the efficiency to a mark of 83.56 %. The maximum efficiency of removing copper in the experiment obtained was 51.72 %. The pH of the soil remained in the range of 7–8 throughout the experiment showing high pH buffering capacity of the soil. Electrical conductivity increased at the end section of the soil cell and all the experiments showed similar results. This electrokinetic remediation process is further supplied with an adsorption zone. Three different adsorbents activated charcoal, steel slag and saw dust were used. The maximum removal efficiency obtained is 63.95 % when saw dust is used in the section close to cathode.

Coupled with EDDS and approaching anode technique enhanced electrokinetic remediation removal heavy metal from sludge.

In this work, the novel technology was used to remove heavy metal from sludge. The coupled with biodegradable ethylenediamine disuccinic acid (EDDS) and approaching anode electrokinetic (AA-EK) technique was used to enhance heavy metal removing from sludge. Electric current, sludge and electrolyte characteristics, heavy metal removal efficiency and residual content distribution, and heavy metal fractions percentage of variation were evaluated during the electrokinetic remediation process. Results demonstrated that the coupled with EDDS and AA-EK technique obtain a predominant heavy metal removal efficiency, and promote electric current increasing during the enhanced electrokinetic remediation process. The catholyte electrical conductivity was higher than the anolyte, and electrical conductivity of near the cathode sludge achieved a higher value than anode sludge during the coupled with EDDS and AA-EK remediation process. AA-EK technique can produce a great number of H+, which caused the sludge acidification and pH decrease. Cu, Zn, Cr, Pb, Ni and Mn obtain the highest extraction efficiency after the coupled with EDDS and AA-EK remediation, which were 52.2±2.57%, 56.8±3.62%, 60.4±3.62%, 47.2±2.35%, 53.0±3.48%, 54.2±3.43%, respectively. Also, heavy metal fractions analysis demonstrated that the oxidizable fraction percentage decreased slowly after the coupled with EDDS and AA-EK remediation.

Optimization of electro-kinetic process for remediation of soil contaminated with phenanthrene using response surface methodology.

The objective of this work was to investigate the modification of soil contaminated with phenanthrene (PHE) by electro-kinetic remediation (EKR) process using response surface methodology (RSM). The soil sample was obtained from the subgrades (0-30 cm) of an area close to Shahroud City, Northeast of Iran. The effect of variables such as initial pH, voltage, electrolyte concentration, and reaction time on PHE removal was studied. Based on the results obtained from the central composite design (CCD) experiment, the highest and lowest amount of PHE removal was 97 and 20%, respectively. In this study, the variables A, B, C, AB, AC, and C2 with a p value < 0.05 were significant model terms and the parameter of the lack of fit was not significant (p value = 0.0745). Findings indicated that the "predicted R-squared" of 0.9670 was in reasonable agreement with the "adj R-squared" of 0.9857 and the plot of residual followed a normal distribution and approximately linear. Also, the kinetic rates of the removal PHE by the EKR process best fitted with a first-order kinetic model (R2: 0.926). Results of the investigation of the effective variables showed that in values of pH 3, time of 168 h, voltage of 3 V, and electrolyte concentration of 4 mg/L, the removal efficiency of PHE reached 96.6%. Graphical abstract.