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BACKGROUND: Ammonia removal from wastewater by electrooxidation (EO) is an interesting approach because of its efficiency and easy maintenance and operation. In this process, ammonia is oxidized to nitrate or nitrogen gas. Ammonia conversion to the latter is desirable to remove nitrogen from the liquid; however, the influence of several operating parameters on nitrate generation has not been systematically evaluated. Therefore, this work aimed to investigate the effect of current density (200–800 A m−2), chloride concentration (0–10 000 mg L) and initial pH (5–9) on the electrooxidation of an ammonia‐containing solution and the associated generation of nitrate. For this purpose, a laboratory‐scale electrochemical reactor containing two Ti/RuO2 electrodes was used. RESULTS: The results indicated high ammonia removal efficiency – 98% within 150 min at 800 A m−2 and 97% within 240 min at 500 A m−2 – generating around 70 and 102 mg NO3−‐N L−1 under these conditions, respectively. Increasing the chloride concentration from 5000 to 7500 mg L−1 reduces the electrolysis time needed to remove all ammonia from 180 to 150 min. However, with increasing initial chloride concentration, the amount of nitrate generated rose from 69.5 to 135.9 mg N L−1. On the other hand, in the test without chloride, nitrate generation was considerably lower (0–0.61 mg L−1). CONCLUSION: The higher the current density applied, the greater the ammonia removal by EO. Although current density influenced the ammonia oxidation rates, it did not directly affect nitrate formation. The lower the concentration of ammonia in the solution, the more significant was the fraction of nitrate generated. Most of the inlet ammonia was oxidized to nitrogen gas, nitrite was rapidly oxidized to nitrate and higher chloride concentrations enhanced ammonia oxidation. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Abstract An improved electroosmotic method is proposed in this paper to enhance the non-uniform effect and efficiency of electroosmotic process. Such method is electroosmotic flow with injection of calcium chloride through the anode, followed by injection through the central tube (a tube at the midpoint between the anode and the cathode) with a suitable time interval between injections. Experimental results indicate that using this method can significantly improve the non-uniform reduction in water content throughout the soil, mitigate the formation of cracks in the anode section, and therefore considerably inhibit the increase in the electric resistance. After treatment, the drained water could be raised to 3.59 times more than that of pure electroosmotic flow, and 1.3 times that of simultaneous injection through both the anode and the central tube with considerably slight increase in power consumption. Moreover, the area of cementation was also expanded, approximately twice larger than that of pure electroosmotic flow and one and a half that of simultaneous injection. It is also worth noting that the proposed method performs better with the same power consumption. The results demonstrate that electroosmotic flow with a suitable time interval between injections could improve the efficiency of electroosmotic process and expand the treatment region in soils, hence can be a promising and economic technique for soil improvement in practical engineering.

An improved electroosmotic method is proposed in this paper to enhance the non-uniform effect and efficiency of electroosmotic process. Such method is electroosmotic flow with injection of calcium chloride through the anode, followed by injection through the central tube (a tube at the midpoint between the anode and the cathode) with a suitable time interval between injections. Experimental results indicate that using this method can significantly improve the non-uniform reduction in water content throughout the soil, mitigate the formation of cracks in the anode section, and therefore considerably inhibit the increase in the electric resistance. After treatment, the drained water could be raised to 3.59 times more than that of pure electroosmotic flow, and 1.3 times that of simultaneous injection through both the anode and the central tube with considerably slight increase in power consumption. Moreover, the area of cementation was also expanded, approximately twice larger than that of pure electroosmotic flow and one and a half that of simultaneous injection. It is also worth noting that the proposed method performs better with the same power consumption. The results demonstrate that electroosmotic flow with a suitable time interval between injections could improve the efficiency of electroosmotic process and expand the treatment region in soils, hence can be a promising and economic technique for soil improvement in practical engineering. [ABSTRACT FROM AUTHOR]

Hydrogen plays a leading role in achieving a future with net zero greenhouse gas emissions. The present challenge is producing green hydrogen to cover the fuel demands of transportation and industry to gain independence from fossil fuels. This review's goal is to critically demonstrate the existing methods of biomass treatment and assess their ability to scale up. Biomass is an excellent hydrogen carrier and biomass-derived processes are the main target for hydrogen production as they provide an innovative pathway to green hydrogen production. Comparing the existing processes, thermochemical treatment is found to be far more evolved than biological or electrochemical treatment, especially with regard to scaling prospects. [ABSTRACT FROM AUTHOR]

ObjectivesThe aim of this study was to investigate the impact of electrochemical treatment of a titanium surface employing constant current and potential on the viability of the tissue cells attached to the surface and determining the safety limits for this type of treatment.MethodsPre-osteoblast cells (pOB) were cultured and seeded onto titanium discs. The cell-seeded discs were then exposed to a range of contant direct electrical potentials (-6V–6V) or contant direct electrical currents (−12.5 mA, −25 mA, or −50 mA) using a three-electrode system connected to a potentiostat. Cell viability was assessed using live/dead assay and fluorescence microscopy.ResultsExposure of cells to high negative potentials caused cell detachment, while exposure to positive ones led to cell death on the cpTi surfaces. However, cellular viability was preserved when the electrical potentials were kept between −3 and +3 V. Cells retained 80% viability when subjected to −12.5 mA currents with an initial pOB cell count of 5 × 104. However, when the initial cell count was elevated to 1 × 105, the cells demonstrated the ability to withstand an even greater current (−25 mA) while preserving their vitality at the same level.ConclusionTreatment of a titanium dental implant surface employing constant potential or current can harm cells surrounding dental implants. However, this damage can be minimized by keeping the potential within a safety limit.

Hydrogen plays a leading role in achieving a future with net zero greenhouse gas emissions. The present challenge is producing green hydrogen to cover the fuel demands of transportation and industry to gain independence from fossil fuels. This review’s goal is to critically demonstrate the existing methods of biomass treatment and assess their ability to scale up. Biomass is an excellent hydrogen carrier and biomass-derived processes are the main target for hydrogen production as they provide an innovative pathway to green hydrogen production. Comparing the existing processes, thermochemical treatment is found to be far more evolved than biological or electrochemical treatment, especially with regard to scaling prospects.

One of the main challenges in processing fresh ferruginous quartzites is to obtain high-quality iron ore concentrates containing more than 70% total iron and less than 1.8% silica to produce DR pellets and hot Briquetted Iron (HBI). Currently, it is widely recognized that the most effective methods to achieve high-quality iron ore concentrates is through reverse flotation using cationic amine collectors in an alkaline medium. However, due to the very fine impregnation of magnetite in quartz, the insufficiently complete release of magnetite even with fine grinding, and the proximity of the flotation (surface) behavior of the separated minerals, high-quality concentrates are not always achievable in the flotation process. Consequently, exploring methods to enhance the efficiency of flotation separation of minerals and improve concentrate quality remains a pertinent issue. Historical studies have shown that electrochemical treatment can adjust the properties of reagents, enhance their effect on specific minerals, and thus control the flotation process. The efficiency of quartz and other silicates flotation by amines significantly depends on the ratio of ionic and molecular forms of the reagent in aqueous solutions of the collector and in the flotation pulp. Altering this ratio can impact the outcomes of reverse cationic flotation of iron ores. It is feasible to change the ratio of the amine forms through electrochemical oxidation or reduction of the reagent solution. Moreover, the electrochemical treatment facilitates the dispersion of the amine in the aqueous medium and its physical adsorption on minerals. Therefore, electrochemical pretreatment of amines can be considered a promising method for intensifying the reverse flotation of iron ore. This paper presents research results aimed at improving the quality of the oversize of the fine screening of ordinary magnetite concentrate from Mikhailovsky GOK, named after A.V. Varichev, through the use of electrochemically treated solutions of cationic amine class collectors in the process of reverse cationic flotation. The research findings confirmed the feasibility of using preliminary diaphragmless electrochemical treatment of reagents Tomamine RA-14 and Lilaflot 811M (esters of monoamine of different composition) for the targeted modification of their properties and for increasing the efficiency of reverse flotation. Consequently, the silica content in the flotation cell product decreased from 1.66–1.7% to 1.51–1.56, with the grade of total iron exceeding 70%.

Solid‐waste management, particularly of aluminum (Al), is a challenge that is being confronted around the world. Therefore, it is valuable to explore methods that can minimize the exploitation of natural assets, such as recycling. In this study, using hazardous Al waste as the main electrodes in the electrocoagulation (EC) process for dye removal from wastewater was discussed. The EC process is considered to be one of the most efficient, promising, and cost‐effective ways of handling various toxic effluents. The effect of current density (10, 20, and 30 mA/cm2), electrolyte concentration (1 and 2 g/L), and initial concentration of Brilliant Blue dye (15 and 30 mg/L) on the efficiency of the EC process were examined in this study. The results show that removal efficiency increased with current density and sodium chloride (NaCl) concentration and decreased with initial dye concentration. The electrical power and electrodes consumed increased with an increase in current density and decreased notably with increased NaCl. The optimum current density and amount of NaCl were 20 mA/cm2 and 2 g/L, respectively to attain highest values of E133 brilliant blue dye removal. The EC process was examined using adsorption isotherms and kinetics models. Those results showed that the Langmuir isotherm matched the experimental data. Furthermore, the experimental data were followed the Elovich model kinetics. [ABSTRACT FROM AUTHOR]

This study investigates the impact of a combined approach involving sandblasting and electrochemical surface treatment using a deep eutectic solvent Ethaline, a eutectic mixture of choline chloride and ethylene glycol, on the surface characteristics of Ti–6Al–4V biomedical substrates fabricated through direct selective laser melting (DSLM). Research has focused on surface morphology, topography, chemical composition, and cell adhesion. The novel approach demonstrated the ability to create a hierarchical surface structure with both micro and nanopatterns. The rough edges resulting from the sandblasting process were effectively smoothed through subsequent electrochemical processing. Additionally, the issue of residual sand particles, which commonly arise in sandblasting procedures, was successfully addressed with the new method. The results indicated that Ti alloy samples subjected to sandblasting and electrochemical treatment in Ethaline exhibited improved surface hydrophilicity. In-vitro cell adhesion tests confirmed the potential for bio-inspired properties of DSLM-printed Ti–6Al–4V biomedical substrates achieved through the combination of sandblasting and electrochemical processing in Ethaline.

In this study, COD, turbidity, total nitrogen, phosphate, sulphate, oil-grease and chromium removals from wastewaters taken from a local tannery using the electrocoagulation process were examined and the most suitable parameters for the electrocoagulation system were tried to be determined. Soluble iron plate electrodes were used as electrodes in the experiments. As a result of the studies carried out, the most suitable initial pH in uncontrolled pH was determined as pH = 4 and for controlled pH as pH = 5. In studies, the most suitable current density for iron electrodes was determined as 1.2 mA cm−2. Even if the increase in current density increased the amount of dissolved Fe, it negatively affected the removal efficiency. In addition, the turbidity of the wastewater was removed in 30 minutes, phosphate in 20 minutes and chromium in 15 minutes by 100%. During 60 minutes of operation, while 62.91% of TN, 87.8% of oil-grease were removed, sulphate was removed at the rate of 54.78%. In the studies, 1st and 2nd order kinetic equations for COD removal were examined and it was determined that removal kinetic is more suitable for 2nd order kinetics. [ABSTRACT FROM AUTHOR]

The development of recovery processes has become essential in recent years as a strategy to minimize environmental pollution while boosting circular economy and sustainable development. Due to the exponential growth in agricultural production and the increased pollution of waterbodies, the production of fertilizers from recovered phosphorus has become an alternative to phosphate rock-based production. In this work, the effect of different operational parameters in the efficiency of the electrochemical recovery of phosphorus, from organic and inorganic sources, was investigated. Among the studied variables, the most significant was the electrode material utilized in the system. The use of magnesium sacrificial electrodes, as AZ31 alloys, led to phosphorus removal from solution of above 90%, allowing the recovery of both orthophosphates and organic phosphorus (glyphosate) as struvite, brucite, and other amorphous compounds. Since there is a lack in the literature about the use of magnesium electrodes in real wastewater electrochemical treatment, system efficiency was also evaluated using a sanitary landfill leachate, reaching 96% of phosphorus recovery. The specific energy consumption and faradaic efficiency of the phosphorus recovery process were also assessed. [ABSTRACT FROM AUTHOR]

The use of additive technologies for manufacturing parts from stainless steel powders is continuously increasing in the recent time. The application of the layer-by-layer selective laser melting technology provides economy of a material for the growth of the final part, reduces the labor capacity of manufacturing, and gives parts of various configurations. At the same time, additive technologies are characterized by an increased surface roughness of the produced parts, which implies, in most cases, the application of finishing surface treatment. The influence of electrolytic polishing on the roughness of the specimens produced by selective laser melting from a 12Kh18N10T steel powder is considered. [ABSTRACT FROM AUTHOR]

Over 5000 public drinking water systems in the US are out of compliance with the Lead and Copper Rule. Lead leaching from lead pipes is limited by the solubility of a naturally occurring scale. Changes in water quality may cause this scale to become more soluble, releasing lead into the drinking water. We propose a novel electrochemical method to prevent lead leaching from lead pipes. In this method, an aluminum wire and an alkaline phosphate electrolyte are inserted into the pipes. The pipes are then anodized for 2 h by using an external power supply, resulting in the electrodeposition of an insoluble aluminum oxide layer on top of the preexisting scale. This technology was tested on lead pipes from the EBMUD water distribution systems located in Berkeley, CA, using recirculating synthetic and actual tap water for 120 days. The untreated pipes leached an average of 23 ppb and 38 ppb of lead respectively, when using free chlorine and monochloramine as disinfection residuals. In contrast, the treated pipes leached 3 ppb and 5 ppb respectively. These results suggest that the proposed treatment has the potential to prevent lead leaching regardless of the disinfection residual and thus should be further explored in a field trial.

Over 5000 public drinking water systems in the US are out of compliance with the Lead and Copper Rule. Lead leaching from lead pipes is limited by the solubility of a naturally occurring scale. Changes in water quality may cause this scale to become more soluble, releasing lead into the drinking water. We propose a novel electrochemical method to prevent lead leaching from lead pipes. In this method, an aluminum wire and an alkaline phosphate electrolyte are inserted into the pipes. The pipes are then anodized for 2 h by using an external power supply, resulting in the electrodeposition of an insoluble aluminum oxide layer on top of the preexisting scale. This technology was tested on lead pipes from the EBMUD water distribution systems located in Berkeley, CA, using recirculating synthetic and actual tap water for 120 days. The untreated pipes leached an average of 23 ppb and 38 ppb of lead respectively, when using free chlorine and monochloramine as disinfection residuals. In contrast, the treated pipes leached 3 ppb and 5 ppb respectively. These results suggest that the proposed treatment has the potential to prevent lead leaching regardless of the disinfection residual and thus should be further explored in a field trial.

Pesticides usage has tremendously increased to enhance crop production; however some pesticides are toxic and harmful to human health and the environment. This review discusses the eco-toxicological impacts of pesticides on the environment. This study extensively evaluates various sustainable remediation technologies such as advanced oxidation processes (AOPs), electrochemical processes, membrane separation, and adsorbent types (carbon nanotubes, carbon nanofiber, carbon aerogel, graphene oxide, carbon dot, biochar, biosorbents, polymers, metal-organic framework, and nanocomposite) that are used for removal of toxic pesticides from aqueous bodies. Further, various equilibrium isotherm and kinetic models that are used for understanding the mechanisms along with challenges in the techniques are discussed. From the studies, it is observed that the nanocomposites could degrade and remove pesticides efficiently due to their unique properties, making them promising adsorbents for water and wastewater remediation. This review will be an inclusive paper for readers to easily define research gaps and develop novel treatment methods for removing pesticide-contaminated waters.

In achieving the European Union's goal of making Europe the first climate-neutral continent by 2050, the scientific community is striving to develop processes and products that are technologically and economically sustainable to replace/substitute fossil-based feedstocks. In this effort, the European project LIBERATE has demonstrated the commercial opportunities of converting low-cost lignin feedstocks into high-value bio sustainable chemicals such as vanillin and mixed phenolic derivatives. Lignin is the largest regenerative source of aromatic organics. In current wood pulping industries, lignin is underutilized and widely considered a side stream primarily exploited for its energy content. A promising approach for the synthesis of biobased fine chemicals is a depolymerisation process for lignin using sodium peroxodicarbonate (PODIC®), an electrochemically produced oxidiser. Within the LIBERATE project, SINTEF has built a pilot scale plant for the electrochemical lignin depolymerisation. The plant provided CHIMAR with the phenol-rich reactor product solution from both kraft and organosolv lignin, which was used as phenol substitutes with up to 50 wt% in the formulation of phenol-formaldehyde (PF) resins. These resins have been able to produce successful plywood panels on a laboratory scale. Although their quality is somewhat lower than that of the reference material with traditional PF resin, this work showed that the use of lignin fractions obtained by electrochemical treatment in such an application is possible and promising.

The microbial fuel cell (MFC) technology is emerging as an effective technology for wastewater treatment to remove and detect many pollutants and simultaneously generate power. The anode is an essential component for bacterial attachment and extracellular electron transfer (EET). Thus, anode performance is critical for improving an MFC system's overall performance. Materials that are electronically conductive and provide favorable conditions for creating biofilm are good candidates for the anode. Carbon paper and carbon felt are the most used anode materials. However, the characteristics of these materials can be modified to increase their performance. This paper presents a modification of the conventional carbon anode by electrolyzing the carbon felt in a phosphate buffer and an experimental evaluation of the impact of the treatment. The tests were performed using an air cathode MFC, electrogenic bacteria Shewanella Baltica 20 fed on lactose-rich L-B. The treatment with phosphate buffer generates functional groups on the surface of the carbon felt, which establishes robust biofilm on the anode and offers lower charge-transfer resistance compared to the untreated carbon felt. This facilitates electron transfer from exoelectrogens to the anode, increasing the current density and power density output. Three times higher power density was observed in the cell with a modified anode than in an untreated carbon-felt anode.

Owing to the widespread use of electronic devices, energy harvesting technologies have attracted enormous attention to fulfill the soaring energy demands. Considering this, a generator based on the magnetoelectric (ME) effect is proposed as a promising energy harvesting device. As one class of ME materials, polymer-based ME laminates consisting of piezoelectric (PE) and magnetostrictive (MS) phases convert magnetic fields to electric voltage by strain transfer between the PE and MS phases. Herein, P(VDF-TrFE)/nano-porous Ni (P/np-Ni) binderless laminates were designed to investigate the ME voltage in polymer-based ME laminates by regulating the surface morphology of MS substrate. To implement a binderless state, nano-porous Ni (np-Ni) substrates were prepared via an electrochemical treatment. The morphology of np-Ni substrates was electrochemically adjusted with different treatment conditions. As a result, from P/np-Ni binderless laminates, an optimal ME coefficient of 8.41 (±1.00) mV/cm•Oe was achieved by a stable physical adhesion between the PE polymer and MS nano-porous structures. Moreover, the different ME voltage tendency according to interfacial morphology in the binderless laminates demonstrates the suitable interface configuration for polymer-based ME laminates as energy harvesting devices.

The aim of this study is to utilize the electromembrane extraction (EME) system as a manner for effective removal of zinc from aqueous solutions. A novel and distinctive electrochemical cell design was adopted consisting of two glass chambers, a supported liquid membrane (SLM) housing a polypropylene flat membrane infused with 1-octanol and a carrier. Two electrodes were used, a graphite as anode and a stainless steel as cathode. A comprehensive examination of several influential factors including the choice of carrier, the applied voltage magnitude, the initial pH of the donor solution, and the initial concentration of zinc was performed, all in a concerted effort to ascertain their respective impacts on the efficiency of zinc elimination. Two distinct carriers, namely tris(2-ethylhexyl) phosphate (TEHP) and bis(2-ethylhexyl) phosphate (DEHP) were evaluated, in a tandem with utilization of 1-octanol. The results revealed essential role played by the applied voltage in augmenting the rate of mass transfer of zinc across the membrane. The best operating conditions were utilized for 1-octanol enriched with 1.0 vol.% bis(2-ethylhexyl) phosphate as a carrier, applied voltage of 60 V, initial pH of 5, initial zinc concentration of 15 mg L-1, extraction duration of 6 hours, and stirring rate of 1000 rpm. Surprisingly, operating under these meticulously devised conditions culminated in the outstanding removal efficiency of 87.3 %. In comparison with no applied voltage, a substantial enhancement in removal efficiency was observed, trans­cending from a meager 36.67 % to an impressive 87.3 % at 60 V, suggesting thus a tremen­dous potential of EME as an efficacious technique for the elimination of heavy metals.

Conservation interventions on silver tarnish and corrosion layers include mechanical, chemical, and electrolytic techniques. Electrolytic reduction is still disputed among metal conservators. The prevailing conviction with many is that mechanical cleaning methods are more likely to maintain control over the result than electrochemical methods. A survey on this subject undertaken in Germany and Austria suggested that this may be due to the traditional approaches of academic education. An electrolytic pencil was further developed and has been applied on naturally aged silver artefacts of the nineteenth and twentieth centuries. The influence of the electrochemical potential difference between artefact and counter electrode as well as of the tip diaphragm material was evaluated. A minimized material loss and a good controllability of conservation interventions on silver alloys were demonstrated. [ABSTRACT FROM AUTHOR]

The rising number of new contaminants in the environment continues to raise deep concern. Pollutant removal from wastewaters has always been critical for maintaining the quality of the available water resources. Carbon-based nanomaterials have received special attention due to their large specific surface area and associated adsorption sites, carbon nanotubes (CNT) have attracted in environmental remediation, particularly in wastewater treatment. In this regards, disposal of pharmaceutical wastewater is given greater consideration, and appropriate steps are taken to ensure safety. CNT have been successfully used to remove the pharmaceutical pollutant by electrochemical treatment. CNT are prepared using the chemical vapor deposition method and are coated on anode electrodes. Synthesis of the Carbon nanotubes were characterized by different advanced analytic techniques represents the presence of 1.09–3.89 nm of the particle size with 12.9 mV of zeta potential. High resolution XPS spectra of C 1 s gives one peak situated at 284.68 eV equivalent to C–C bond and for O 1 s can be expanded into two peaks located at 529.4 eV and 531.44 eV which are related to lattice oxygen and oxygen vacancies. The Raman spectrum of CNT shows the ID/IG ratio as 0.85, which demonstrate clearly the purity of product. Statistical analysis of variance (ANOVA) has carried to confirm the efficiency. Three independent variables like pH, voltage, and Dosage are selected and the R2 value obtained have been ranged from 0.6 to 0.8. Response surface methodology is adapted to achieve high efficiency of CNT. As a result, after conventional waste water treatment CNT efficiently removed pharmaceutical pollutants in waste water, and further analysis revealed that pollutant removal ranged from 83.0 to 91.5%. [ABSTRACT FROM AUTHOR]

The textile industry utilizes numerous chemicals ranging from solvents to resins and caustic soda to bleach, having a harsh environmental impact. A large amount of colored dye in wastewater is released. Non‐biodegradable heavy metals and chlorine accumulate in organs of marine and terrestrial life, leading to various diseases. So, there is an urgent need to treat textile wastewater. Up to date, techno‐economic analyses of all electrochemical processes have not been reviewed for textile wastewater treatment. In this review, the focus is on the tertiary treatment methods, mainly on electrochemical treatments, i.e., electrocoagulation, electro‐Fenton, electrooxidation, photoelectrochemical (PEC) process, and solar electrophoto‐Fenton process (SPEF) with their mechanisms and techno‐economic analyses. SPEF treatment was found to be advantageous in terms of efficiency and economic perspective as it utilizes solar energy instead of electrical energy and the cost of the PEC process can also be recovered by the generation of hydrogen. [ABSTRACT FROM AUTHOR]

The research shows the benefits provided by the use of electrochemical treatment, with the application of impressed current combining the use of a porous medium for the dechlorination of large iron structures removed and/or located in the marine environment. Considering the previous work for the dechlorination of the paddle wheel of the shipwreck “Patris”, located in the Aegean Sea, this study aims to determine the optimum parameters of the amount of current density, the time and the use of the porous medium to stimulate the chloride ion diffusion into an alkaline solution. Specimens of wrought iron coming from the shipwreck were electrochemically treated and the efficiency of the method was verified by the determination of the chloride concentration removal using a chloride ion selective electrode. Samples of corrosion products before and after treatment were analyzed for chloride content using SEM-EDX analysis. The results found that changing the porous medium every 24 h with replenished alkaline solution and using a stainless steel mesh is the best approach for the dechlorination of the specimens. This electrochemical method, is economical and fast, and can be applied to the conservation of large iron structures in situ, coming from and/or located near a marine environment with less waste than the traditional dehlorination methods.

The large volume of consumed water and pigments in the textile industry subsequently produces hazardous wastewater, which potentially may cause serious environmental problems. On the other hand, due to water stress in Iran, the need for further treatment of this wastewater is more urgent. In recent years, electrochemical processes have been considered as an efficient process. The lack of information to build large-scale electrical coagulation units has led to the deficiency of extensive application of this method in industrial units. In this paper, the removal of color and COD in the wastewater of a textile factory in Tehran has been studied in order to determine the efficiency of the electrocoagulation process and to find optimal operation parameters. Optimum distance between the electrodes (4 cm), optimum electrical potential (40 V) and electrolyte concentration (4 mgNaCl/L) are the main achievement of this research. The treatment efficiency achieved in this research is 69% for COD and 96% for color removal.

Tyrosine (l-Tyr), which is found in basic foods, is a nonessential amino acid and a metabolite of phenylalanine, has many roles in human metabolism, and is important in maintaining nutritional balance. In this study, an electrochemical method has been presented to determine low levels of l-Tyr using an electrochemically treated pencil graphite electrode (EPGE) via overoxidation of graphite surface and intercalation of Li+ ions into graphite by cyclic voltammetry in the potential range between −0.3 and 2.0 V. Characterization studies of the EPGEs were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, and cyclic voltammetry. The determination of l-Tyr was performed by differential pulse voltammetry, and the investigation of electrochemical properties of l-Tyr was conducted by cyclic voltammetry. The results showed that the EPGE presents high electrocatalytic performance and has a low detection limit (0.12 μM) for determining l-Tyr with a wide linear range from 1.0 to 500 μM. The selectivity of prepared EPGE was investigated in the presence of organic species. The determination of l-Try was performed in yoghurt and milk samples and good results were obtained with recoveries between 95.7% and 103.1%. Stability and repeatability studies further demonstrate the applicability of the sensor. [ABSTRACT FROM AUTHOR]

Various types of dyes and other hazardous pollutants used in the textile industry are one of the leading pollutants of surface water. In this study, real textile wastewater was electrochemically treated with two different electrode combinations (graphite/graphite and iron/graphite) by changing the anode electrode type. Comparison studies were carried out by adding Fe2+ or H2O2 to these combinations to improve Chemical Oxygen Demand (COD) removal. Current density (5, 7.5, 10 mA cm−2), initial pH (2.5–8), and electrochemical (EC) oxidation time (0–120 min) were investigated to determine the optimum electrooxidation conditions. The results showed that in the electro-oxidation (EO) process, 100% colour removal, and 75.39% COD degradation efficiencies were achieved at pH 5.5, current density (I) 7.5 mA cm −2, and electrolysis time (t) 40 min. In the peroxi-coagulation (PC) process, 89.41% colour removal, and 74.28% COD degradation efficiencies were achieved at pH 3, current density 7.5 mA cm −2, and electrolysis time 120 min. In the EO + Fe+2 and PC + H2O2 processes, 99.9% colour removal efficiencies, 96.38 and 90.63% COD degradation efficiencies were reached at pH 3, current density 7.5 mA cm −2, and electrolysis time 40 min., respectively. In systems using EO, PC, EO + Fe2+and PC + H2O2, energy consumption, and operating cost were estimated as 2.85, 2.34, 0.54, 0.62 kWh m−3, and 0.304, 0.249, 0.199, 3.466 US$ m−3, respectively. Among all processes applied in the study, the most efficient one in terms of COD removal performance, energy, and cost is the (EO + Fe2+) system. [ABSTRACT FROM AUTHOR]

There is a critical need for re-evaluation of electrochemical therapy (EChT) approaches of solid tumors to address the challenges of the currently used method: incomplete pathological response. The coexistence of anode and cathode in the tumor region resulted in acid–alkaline mixation (buffered pH) when the electrodes are so near each other (d < 1 cm), and in the non-affected lesions when the electrodes are far from each other (d > 1 cm), both have resulted in intact tumoral lesions in EChT field. Here, we presented a designation model study of EChT with an external anode out of the tumor and filled the tumor with dense distribution of cathode electrodes to completely destroy the tumoral lesions without any remaining vital tumoral residues. Anode was located in a biological ionic gel chamber (located on top of the skin) which mediates the ionic interface between the external anode and intratumoral cathode. Our newly reported method can solve the lack of a comprehensive therapeutic guideline for any solid tumors. A remarkable increase in the efficiency of EChT without any over-treating was achieved by alkaline therapy of the tumor (without any limitation in locating cathodic needles all over the tumor) and an external acidic region on top of the skin in a cylindrical gel chamber. We found that the destructive volumes and treating ability of mice tumors by this newly represented method were more significant than the conventional EChT method in fewer therapy sessions and no damage to the skin (both anode and cathode electrodes inside the tumor) (P < 0.05). Results of this study applied to mouse model tumors shed new light on returning attraction to EChT as a valuable complementary method for treating different types of solid breast tumors. [ABSTRACT FROM AUTHOR]

The persistence of microplastics (MPs) in agricultural lands using plastic mulch will be an issue of major environmental concern in meeting the sustainable development goals (SGDs) of the near future. This research work aims at identifying and removal of MPs from rainfall runoff water (RRW) from MP-contaminated agricultural lands using the novel electrochemical coagulation (ECC) treatment technology. The MPs were extracted from the soil samples before identification. The pH, moisture content, MP abundance in soil, and particle size were determined. The RRW from the agricultural land loaded with MPs was treated using stainless steel (SS) electrodes in an electrochemical reactor. The removal efficiency of MPs, COD, chloride, and TDS at 45 min electrolyzing time was 98%, 46%, and 48%, respectively. Higher percentages of MP removal were achieved for increased MP concentrations in RRW. The difference in dry sludge generated during ECC for raw RRW and MP-loaded RRW was 2.42–4.09 kg/m3 of RRW treated. SEM, EDS, and ATR-FTIR spectroscopy analysis revealed the disintegration pattern of MPs into nano-sized particles. EDS of agricultural soil showed 8.2% carbon and 48.1% oxygen, whereas MP particles showed 62–64% carbon and 20–22% oxygen, respectively. The ATR-FTIR spectra for both spiked and extracted MP particle from the contaminated soil showed C–H stretch, CH2 bends, etc.; the MP particle was identified as LDPE-type plastic mulch. The EDS of ECC sludge showed loads of MPs with 47% C, 35% O, 1.6–2.3% Al, 2–2.6% Si and 10.3–12.9% Fe. The ECC process showed its effectiveness in 98% MP removal from the RRW in a short hydraulic retention time (HRT) of < 45 min. [ABSTRACT FROM AUTHOR]

The combination of CO2 laser ablation and electrochemical surface treatments is demonstrated to improve the electrochemical performance of carbon black/polylactic acid (CB/PLA) 3D-printed electrodes through the growth of flower-like Na2O nanostructures on their surface. Scanning electron microscopy images revealed that the combination of treatments ablated the electrode's polymeric layer, exposing a porous surface where Na2O flower-like nanostructures were formed. The electrochemical performance of the fabricated electrodes was measured by the reversibility of the ferri/ferrocyanide redox couple presenting a significantly improved performance compared with electrodes treated by only one of the steps. Electrodes treated by the combined method also showed a better electrochemical response for tyrosine oxidation. These electrodes were used as a non-enzymatic tyrosine sensor for quantification in human urine samples. Two fortified urine samples were analyzed, and the recovery values were 106 and 109%. The LOD and LOQ for tyrosine determination were 0.25 and 0.83 μmol L−1, respectively, demonstrating that the proposed devices are suitable sensors for analyses of biological samples, even at low analyte concentrations. [ABSTRACT FROM AUTHOR]

Miniaturized paper‐based electrochemical sensors were fabricated using kraft paper and CO2 laser, dispensing the need for chemical reagents and controlled atmospheric conditions. This study initially evaluated the paper type and laser processing parameters, enhancing the electrodes′ robustness, electrochemical response, and electrical resistance. The sensors were also treated by applying −1 V for 60 s in 1.0 mol L−1 KCl, which is a simple and rapid procedure. The electrochemical treatment increased the electroactive area and roughness, confirmed by scanning electron microscopy. These aspects helped modulate the sensors′ electrochemical response for nitrite determination, improving selectivity and sensitivity for this compound. The sensors also showed repeatability and batch‐to‐batch reproducibility, with 2.2 and 10 % RSD, respectively. Therefore, this work brings a protocol to fabricating competitive electrochemical sensors through a sustainable strategy, opening possibilities for designing new analytical systems. [ABSTRACT FROM AUTHOR]

The research shows the benefits provided by the use of electrochemical treatment, with the application of impressed current combining the use of a porous medium for the dechlorination of large iron structures removed and/or located in the marine environment. Considering the previous work for the dechlorination of the paddle wheel of the shipwreck "Patris", located in the Aegean Sea, this study aims to determine the optimum parameters of the amount of current density, the time and the use of the porous medium to stimulate the chloride ion diffusion into an alkaline solution. Specimens of wrought iron coming from the shipwreck were electrochemically treated and the efficiency of the method was verified by the determination of the chloride concentration removal using a chloride ion selective electrode. Samples of corrosion products before and after treatment were analyzed for chloride content using SEM-EDX analysis. The results found that changing the porous medium every 24 h with replenished alkaline solution and using a stainless steel mesh is the best approach for the dechlorination of the specimens. This electrochemical method, is economical and fast, and can be applied to the conservation of large iron structures in situ, coming from and/or located near a marine environment with less waste than the traditional dehlorination methods. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of electrochemical treatment based on cyclic voltammetry (100 cycles with a scan rate of 1 V s−1) on pencil graphite electrode (PGE), using different supporting electrolytes compositions (NaOH, HNO3, and KCl all in 0.1 mol L−1). Electrochemically treated electrodes (ePGE) were properly characterized by scanning electron microscopy, Raman spectroscopy, and X-Ray powder diffraction revealing that the proposed strategy provided an efficient exfoliation of graphene sheets on the electrode surface. Additionally, the ePGE showed a 43-fold increase in the electroanalytical response to ciprofloxacin (CIP) when compared to the untreated electrode. The sensor showed excellent analytical performance with a low detection limit (0.35 µmol L−1), wide working linear range (from 5 to 100 µmol L−1), and adequate precision (RSD < 3.5%). In addition, the sensor provided adequate selectivity about other classes of antibiotics, and when applied to spiked samples, recovery values between 80 and 104% were obtained, which demonstrated satisfactory accuracy, as well as the absence of matrix effect. Thus, the electrochemical treatment provided a simple, fast, and affordable protocol to improve the electrochemical properties of PGE, making it a powerful tool for the investigation of other carbon-based substrates. [ABSTRACT FROM AUTHOR]

In the present study, the treatment of slaughterhouse wastewater (SWW) by electro-oxidation method and the energy consumption of the system during the process were investigated. The removal of chemical oxygen demand (COD), color, turbidity, and suspended solids (SS) from wastewater is emphasized. Ti/IrO2/RuO2 was used as the anode material and uncoated titanium was used as the cathode material in the experiments. The experiments were carried out in a glass reactor; the supporting electrolyte (SE) type, concentration, initial pH value, and current density were studied under different conditions. Na2SO4, NaNO3 NaCl, and KCl salts have been used as SE. Salt studies were carried out at 0.1, 0.2, 0.3 and 0.4 M concentrations. The current density was studied at 4.06 mA/cm2, 6.09 mA/cm2, 8.12 mA/cm2, 10.15 mA/cm2, 12.18 mA/cm2. Studies have been carried out at pH 3–9–11 and natural wastewater pH values. The optimum conditions to be used in electro-oxidation of SWW with high organic content have been determined. The results have revealed that as the current density increased, the efficiency increased, and the highest removal was achieved at the natural pH value of the NaCl salt. Studies have shown that color, turbidity, and SS removal for SWW is approximately 90%. COD was found to be 66.46% at the lowest current density. The energy consumption in the selected optimum conditions was found to be 183.6 kWh/m3. [ABSTRACT FROM AUTHOR]

Wastewater is major source of contaminants originating from the production, usage, and disposal of plastic materials. Due to their poor biodegradability of these contaminants in municipal wastewater treatment plants, additional advanced oxidation processes such as electrochemical treatments have been developed to improve the standard biological treatment. Here we review the applications of electrochemical treatments of wastewater for the removal of the following plastic contaminants: bisphenol A, phthalic acid esters, and benzotriazoles. We present the effectiveness of treatment in terms of contaminant removal and mineralization; the identification of transformation products; toxicity assessment; and process energy requirements. In the present review, we have focused on the applications of electrochemical treatments of wastewater for the removal of three important groups of contaminants originating mainly from plastics: bisphenol A, phthalic acid esters, and benzotriazoles. The review focuses on the research of electrochemical treatments for these contaminants from the last five years. The papers are assessed from the point of i) effectiveness of treatment in terms of contaminant removal and mineralization; ii) identification of transformation products; iii) toxicity assessment; iv) processes' energy requirements. Electrochemical treatments were confirmed to be a viable option for the removal of selected contaminants from wastewater. [ABSTRACT FROM AUTHOR]

• Sulfide-containing wastewater treatments for sulfur and energy recoveries. • Sulfide is a promising electron donor to reduce electricity consumption. • Notable potentials of waste-to-trash and electricity consumption reduction. • Sulfide self-driven potentials of electricity and hydrogen productions. Hydrogen sulfide and dissolved sulfide are notorious and lethal contaminants. The electrochemical process adopting the two-electron sulfide anodic oxidation reaction is an attractive strategy, which can simultaneously recycle and convert the chemical energy and sulfur resources into valued products. Sulfide pollutants are promising electron donors to reduce the electrochemical production cost, which is demonstrated in a sulfide/air fuel cell and a sulfide depolarized electrolyser. Sulfide oxidation behaviors are investigated on the developed Ir x Ru 1-x O 2 catalyst. A sulfide/air fuel cell is applied to evaluate the self-driven abilities of sulfur recovery and electricity generation. The sulfide/air fuel cell exhibits a notable discharge current density of > 120 mA cm−2 for 1.0 mol/L Na 2 S solution and 42.43 ± 1.94 mA cm−2 for the sulfide spent caustic stream. The potentials of sulfide anodic depolarization for electrochemical cost reduction are evaluated in a sulfide depolarized electrolyser for hydrogen production. Its open cell voltage is −0.33 V. For sulfur recovery, the cell can achieve about 20 mA cm−2 at 1.0 V, where the average energy cost of hydrogen production is about 2.39 kWh Nm−3. The sulfide removal rate is 0.26 ± 0.04 kgS m-2h−1, with an average current efficiency of 152.47 ± 28.59 %. This work may shed light on the potential of the incorporation of sulfide contaminants abatement and electrochemical productions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A double-cathode EF synergistic electrocatalytic system was constructed. • This system electrolyzes mariculture wastewater to produce active Cl and *OH. • The EF synergistic EO system can remove pollutants from mariculture wastewater. • Oxidizer reuse system reduces COD and NH 3 -N concentrations. • The optimal treatment of residual chlorine was explored. The salinity properties of mariculture wastewater make it a suitable candidate for electrochemical treatment. In this study, an electro-Fenton synergistic electrocatalytic system was developed using a mixed metal oxide anode, often called Dimensionally Stable Anodes (DSA), and dual cathodes, an iron-carrying activated carbon sheet as the first cathode and a stainless-steel plate as the second cathode, to treat mariculture wastewater. The reaction conditions of the system were investigated and optimized. The chemical oxygen demand (COD) removal rate reached 100 % after 80 min under the optimal conditions: an applied voltage of 3.39 V, a plate spacing of 1.07 cm, and an aeration rate of 34.84 L·h−1. The system effectively removed COD and nitrogen from mariculture wastewater. Analyses using GC–MS, UV–visible spectroscopy, and Fourier-transform infrared spectroscopy showed that the system could degrade macromolecular organic pollutants in the wastewater. Mechanistic studies revealed that active chlorine and hydroxyl radicals play crucial roles in pollutant removal. The dynamic operation study indicated that the optimal operating conditions included a vertical water flow direction through the electrodes, and a flow rate of 10 mL·min−1. The oxidant reuse experiment determined a reflux ratio of 1:1 and a reaction time of 60 min, achieving effluent COD and NH 3 -N concentrations that met the primary discharge standards. The study on residual chlorine removal showed that the input amount of sodium thiosulfate was 0.36 kg, with a treatment cost of 0.32 yuan per ton of water, and the treated effluent met the discharge standards. These results provide a reference for the industrial application of electrochemical methods in treating mariculture wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chemical-free electrochemical treatment reduces SRF by > 98 % in sewage sludge. • Acidification is necessary but not the only factor for dewaterability enhancement. • Cation removal plays a key role in improving dewaterability. • Enhanced flocculation and breakdown of organic matters contribute to dewaterability. Solids dewaterability is vital for water resource recovery facilities to effectively manage and dispose treatment residuals, and current methods for improving dewaterability is at the expense of chemical consumption. Herein, an electrochemical approach that integrates anodic acidification, electrooxidation, and cation removal was investigated to enhance solids dewaterability. The results show that the specific resistance to filtration (SRF) was decreased by > 97 % for raw solids before anaerobic digestion, anaerobically digested solids (ADS), and primary solids. ADS exhibited the highest conductivity and required the least energy (34.9 ± 1.3 kWh m−3 treated solids). Increasing the applied current density reduced treatment time but demanded greater energy consumption. Both acidification and cation removal were critical to dewaterability enhancement: acidification facilitated the flocculation of solids flocs through protonation of functional groups and the leaching of divalent ions, while cation removal reduced competition for proton binding, leading to improved dewaterability. The input of electrical energy for the electrochemical treatment can potentially be offset by revenue from recovered nutrient products and use of renewable energy. This study has demonstrated the feasibility of using electrochemical processes for solids treatment and resource recovery. [ABSTRACT FROM AUTHOR]

The efficient use of wood powder has become increasingly important for protecting the environment and addressing energy shortages. In this study, a proton exchange membrane electrolysis system was utilized to convert biomass into valuable industrial chemicals and hydrogen using ferric ions as redox mediators, reduced reaction costs. GC-MC analysis revealed that the degradation products are mainly consisted of aromatic carbonyl compounds, along with some alcohols, phenols, and alkanes. The degradation efficiency was found to be 55.6 %, and the Faraday's hydrogen production efficiency exceeds 92.6 %. Moreover, Fe3+/Fe2+ redox mediators was recycled in the electrolysis system, maintaining high reactivity. This research introduces a new approach for the degradation of wood powder, offering potential for sustainable industrial production and a reduction in environmental impact. [ABSTRACT FROM AUTHOR]

Abstract Miniaturized paper‐based electrochemical sensors were fabricated using kraft paper and CO2 laser, dispensing the need for chemical reagents and controlled atmospheric conditions. This study initially evaluated the paper type and laser processing parameters, enhancing the electrodes′ robustness, electrochemical response, and electrical resistance. The sensors were also treated by applying −1 V for 60 s in 1.0 mol L−1 KCl, which is a simple and rapid procedure. The electrochemical treatment increased the electroactive area and roughness, confirmed by scanning electron microscopy. These aspects helped modulate the sensors′ electrochemical response for nitrite determination, improving selectivity and sensitivity for this compound. The sensors also showed repeatability and batch‐to‐batch reproducibility, with 2.2 and 10 % RSD, respectively. Therefore, this work brings a protocol to fabricating competitive electrochemical sensors through a sustainable strategy, opening possibilities for designing new analytical systems.

Electrochemical advanced oxidation processes (eAOPs) such as the current advanced oxidation system (AOS) are a type of electrochemical wastewater treatment that creates oxidative species, such as iodide species, chloride species, and hydroxyl radicals, that can treat even the most recalcitrant contaminants. It is important to determine the concentrations and locations of oxidative species in eAOPs for optimization of the wastewater treatment process. In this study, a spectrophotometric methodology was used to determine concentrations of iodide and chloride oxidative species (starting at 10, 25, and 50 ppm) within an AOS under various input voltages (6, 12, and 24 V). Overall, it was found that iodate and chlorite were the dominant species created in their respective treatments. Additionally, the concentration of iodide oxidative species increased with increasing voltage, whereas the chloride species decreased with increasing voltage. The optimal conditions for the efficient creation of AOS oxidative species were 12 V and 10 ppm potassium iodide and 6 V and 10 ppm sodium chloride, respectively. In addition, the use of iodide is recommended for wastewater treatment using the AOS to effectively create oxidative species. Following optimization, the AOS performance was tested for synthetic stormwater. Results indicated that the AOS performed well for reduction of Escherichia coli; however, reduction of other contaminants was inconsistent as would be expected given the AOS was optimized for disinfection, not decontamination. Further AOS optimization for decontamination would be expected to result in improved decontamination performance. [ABSTRACT FROM AUTHOR]