Electrochemical treatments of coking wastewater and coal gasification wastewater with Ti/Ti4O7 and Ti/RuO2-IrO2 anodes

Electrochemical oxidation of Florfenicol in aqueous solution with mixed metal oxide electrode: Operational factors, reaction by-products and toxicity evaluation

Veterinary antibiotics have become an emerging pollutant in water and wastewater sources due to excess usage, toxicity and resistance to traditional water and wastewater treatment. The present study explored the degradation of a model antibiotic- Florfenicol (FF) using electrochemical oxidation (EO) with Ti-RuO2/IrO2 anode. The anode material was characterized using SEM-EDS studies expressing stable structure and optimal interaction of the neighboring metal oxides with each other. The EDS results showed the presence of Ru, Ir, Ti, O and C elements with 6.44%, 2.57%, 9.61%, 52.74% and 28.64% atomic weight percentages, respectively. Optimization studies revealed pH 5, 30 mA cm-2 current density and 0.05 M Na2SO4 for 5 mg L-1 FF achieved 90% TOC removal within 360 min treatment time. The degradation followed pseudo-first order kinetics. LC-Q-TOF-MS studies revealed six predominant byproducts illustrating hydroxylation, deflourination, and dechlorination to be the major degradation mechanisms during the electrochemical oxidation of FF. Ion chromatography studies revealed an increase in Cl-, F- and NO3- ions as treatment time progressed with Cl- decreasing after the initial phase of the treatment. Toxicity studies using Zebrafish (Danio rerio) embryo showed the treated sample to be toxic inducing developmental disorders such as pericardial edema, yolk sac edema, spinal curvature and tail malformation at 96 h post fertilization (hpf). Compared to control, delayed hatching and coagulation were observed in treated embryos. Overall, this study sets the stage for understanding the effect of mixed metal oxide (MMO) anodes on the degradation of veterinary antibiotic-polluted water and wastewater sources using electrochemical oxidation.

Removal of PAHs, TSS, oils and fats from ammonium-rich coke wastewater by granular filtration

Coke wastewater is a complex industrial wastewater due to its high content of toxic compounds such as cyanides, thiocyanates, phenols, tar, oils, and fats. After a series of treatments, wastewater with a high ammonium content is obtained (around 4,150 mg·L-1). A stripping process is used to reduce it. Certain pollutants in the influent, such as tar, polycyclic aromatic hydrocarbons (PAHs), oils, fats and total suspended solids (TSS), interfere with stripping and therefore must be previously removed. In this study, the performance of a pilot-scale airlift sand filter was evaluated under real conditions for the reduction of the concentration of tar, PAHs, oils, fats and TSS, before stripping. Prior to the sand filter, a cationic flocculant was added to the influent (2 ppm). High (10 mm.min-1), medium (7.5 mm.min-1) and low sand speeds (1.9-2.6 mm.min-1) were assessed. The latter conditions gave the best results: a decrease of 98.2% in TSS, 99.7% in oils, fats and grease and 97.6% in PAHs. The final effluent (≤ 1.6 mg PAHs·L-1, ≤ 5 mg TSS·L-1 and ≤ 0.05 mg·L-1 of fats, oils and grease) was suitable for the stripping process.

Advanced treatment of coking wastewater: Recent advances and prospects

Advanced treatment of refractory industrial wastewater is still a challenge. Coking wastewater is one of coal chemical wastewater, which contains various refractory organic pollutants. To meet the more and more rigorous discharge standard and increase the reuse ratio of coking wastewater, advanced treatment process must be set for treating the biologically treated coking wastewater. To date, several advanced oxidation processes (AOPs), including Fenton, ozone, persulfate-based oxidation, and iron-carbon micro-electrolysis, have been applied for the advanced treatment of coking wastewater. However, the performance of different advanced treatment processes changed greatly, depending on the components of coking wastewater and the unique characteristics of advanced treatment processes. In this review article, the state-of-the-art advanced treatment process of coking wastewater was systematically summarized and analyzed. Firstly, the major organic pollutants in the secondary effluents of coking wastewater was briefly introduced, to better understand the characteristics of the biologically treated coking wastewater. Then, the performance of various advanced treatment processes, including physiochemical methods, biological methods, advanced oxidation methods and combined methods were discussed for the advanced treatment of coking wastewater in detail. Finally, the conclusions and remarks were provided. This review will be helpful for the proper selection of advanced treatment processes and promote the development of advanced treatment processes for coking wastewater.

Overview of enhancing biological treatment of coal chemical wastewater: New strategies and future directions

Coal chemical wastewater (CCW) is a type of refractory industrial wastewater, and its treatment has become the main bottleneck restricting the sustainable development of novel coal chemical industry. Biological treatment is considered as an economical, effective and environmentally friendly technology for CCW treatment. However, conventional biological process is difficult to achieve the efficient removal of refractory organics because of CCW with the characteristics of composition complexity and high toxicity. Therefore, seeking the novel enhancement strategy appears to be a favorable solution for enhancing biological treatment efficiency of CCW. This review focuses on presenting a comprehensive picture about the exogenous enhancement strategies for CCW biological treatment. The performance and potential application of exogenous enhancement strategies, including co-metabolic substrate enhancement, biofilm filler enhancement, adsorption material enhancement and conductive mediator enhancement, were expounded. Meanwhile, the enhancing mechanisms of different strategies were comprehensively discussed from a biological perspective. Furthermore, the prospects of enhancement strategies based on the engineering performance, economic cost and environmental impact (3E) evaluation were introduced. And novel enhancement strategy based on "low carbon emissions", "resource recycling" and "water environment security" in the context of carbon neutrality was proposed. Taken together, this review provides technical reference and new direction to facilitate the regulation and optimization of typical industrial wastewater biological treatment.

Research on the descaling characteristics of a new electrochemical water treatment device

In recent years, chemical water treatment equipment has gained significant attention due to its environmental-friendly features, multifunctionality, and broad applicability. Recognizing the limitations of existing chemical treatment equipment, such as challenges in scale removal and the high water content in scale deposits, we propose a novel drum design for both anode and cathode, enabling simultaneous scale suction and dehydration. We constructed a small experimental platform to validate the equipment's performance based on our model. Notably, under the optimal operating parameters, the hardness removal rate for circulating water falls within the range of 19.6-24.46%. Moreover, the scale accumulation rate per unit area and unit time reaches 13.7 g h-1 m-2. Additionally, the energy consumption per unit weight of the scale remains impressively low at 0.16 kWh g-1. Furthermore, the chemical oxygen demand (COD) concentration decreased from an initial 106.0 mg L-1 to a mere 18.8 mg L-1, resulting in a remarkable total removal rate of 82.26%. In conclusion, our innovative electrochemical water treatment equipment demonstrates exceptional performance in scale removal, organic matter degradation, and water resource conservation, offering valuable insights for future research and development in chemical treatment equipment and electrochemical theory.

Strategic analysis on development of simultaneous adsorption and catalytic biodegradation over advanced bio-carriers for zero-liquid discharge of industrial wastewater

With rapid industrial development, millions of tons of industrial wastewater are produced that contain highly toxic, carcinogenic, mutagenic compounds. These compounds may consist of high concentration of refractory organics with plentiful carbon and nitrogen. To date, a substantial proportion of industrial wastewater is discharged directly to precious water bodies due to the high operational costs associated with selective treatment methods. For example, many existing treatment processes rely on activated sludge-based treatments that only target readily available carbon using conventional microbes, with limited capacity for nitrogen and other nutrient removal. Therefore, an additional set-up is often required in the treatment chain to address residual nitrogen, but even after treatment, refractory organics persist in the effluents due to their low biodegradability. With the advancements in nanotechnology and biotechnology, novel processes such as adsorption and biodegradation have been developed, and one promising approach is integration of adsorption and biodegradation over porous substrates (bio-carriers). Regardless of recent focus in a few applied researches, the process assessment and critical analysis of this approach is still missing, and it highlights the urgency and importance of this review. This review paper discussed the development of the simultaneous adsorption and catalytic biodegradation (SACB) over a bio-carrier for the sustainable treatment of refractory organics. It provides insights into the physico-chemical characteristics of the bio-carrier, the development mechanism of SACB, stabilization techniques, and process optimization strategies. Furthermore, the most efficient treatment chain is proposed, and its technical aspects are critically analysed based on updated research. It is anticipated that this review will contribute to the knowledge of academia and industrialist for sustainable upgradation of existing industrial wastewater treatment plants.

Highly efficient electro-Fenton process on hollow porous carbon spheres enabled by enhanced H2O2 production and Fe2+ regeneration

Electro-Fenton (e-Fenton) is a promising method for wastewater treatment that relies on powerful ·OH generated via the decomposition of electro-generated H₂O₂ catalyzed by Fe²⁺. In this regard, developing a catalyst capable of simultaneously producing H₂O₂ and accelerating Fe²⁺ regeneration is of considerable importance; however, this remains a challenge because of the difficulty in modulating the electronic microenvironment. Herein, a hollow porous carbon sphere catalyst (HPCS) is developed to synchronously enhance H₂O₂ generation and accelerate Fe³⁺/Fe²⁺ cycling by constructing an electron-rich microenvironment via surface curvature regulation. The Fe²⁺ regeneration efficiency reaches 35.5% on HPCS featuring a larger curvature structure (HPCS-TPOS), which is 1.6 times higher than the smaller curvature HPCS-S catalyst (22.8%). Density functional theory reveals that the electron-rich microenvironment on the outer surface of high curvature structure promotes Fe²⁺ regeneration. The H₂O₂ production rate on HPCS-TPOS is 47.2 mmol L^-1 h^-1, exceeding the state-of-the-art e-Fenton catalysts reported. Benefiting from the concurrent high-efficiency of H₂O₂ production and Fe²⁺ regeneration, HPCS-TPOS e-Fenton is demonstrated to be efficient for sulfamethoxazole removal with the kinetic rate of 0.30-0.72 min^-1 at pH 3-7. This work offers new insight into the design of efficient catalysts by rationally regulating curvature structures for wastewater treatment.

Preparation of Porous Ti/RuO2-IrO2@Pt, Ti/RuO2-TiO2@Pt and Ti/Y2O3-RuO2-TiO2@Pt Anodes for Efficient Electrocatalytic Decomposition of Tetracycline

Electrocatalytic oxidation (ECO) has attracted attention because of its high efficiency and environmental friendliness in water treatment. The preparation of anodes with high catalytic activity and long service lifetimes is a core part of electrocatalytic oxidation technology. Here, porous Ti/RuO₂-IrO₂@Pt, Ti/RuO₂-TiO₂@Pt, and Ti/Y₂O₃-RuO₂-TiO₂@Pt anodes were fabricated by means of modified micro-emulsion and vacuum impregnation methods with high porosity titanium plates as substrates. The scanning electron microscopy (SEM) images showed that RuO₂-IrO₂@Pt, RuO₂-TiO₂@Pt, and Y₂O₃-RuO₂-TiO₂@Pt nanoparticles were coated on the inner surface of the as-prepared anodes to form the active layer. Electrochemical analysis revealed that the high porosity substrate could result in a large electrochemically active area, and a long service life (60 h at 2 A cm^-2 current density, 1 mol L^-1 H₂SO₄ as the electrolyte, and 40 °C). The degradation experiments conducted on tetracycline hydrochloride (TC) showed that the porous Ti/Y₂O₃-RuO₂-TiO₂@Pt had the highest degradation efficiency for tetracycline, reaching 100% removal in 10 min with the lowest energy consumption of 167 kWh kg^-1 TOC. The reaction was consistent with the pseudo-primary kinetics results with a k value of 0.5480 mol L^-1 s^-1, which was 16 times higher than that of the commercial Ti/RuO₂-IrO₂ electrode. The fluorospectrophotometry studies verified that the degradation and mineralization of tetracycline were mainly ascribed to the •OH generated in the electrocatalytic oxidation process. This study thus presents a series of alternative anodes for future industrial wastewater treatment.

The efficient treatment of mature landfill leachate using tower bipolar electrode flocculation-oxidation combined with electrochemical biofilm reactors

Mature landfill leachate contains high concentrations of organic and inorganic compounds that inhibit the performance of conventional biological treatment. Nowadays, few single treatment techniques could fulfill the requirements of cleaning mature landfill leachate. In this study, a tower bipolar electrode flocculation-oxidation (BEF-O) reactor and an electrochemical biofilm reactor (EBR) combine device was constructed to effectively treat mature landfill leachate. And the removal efficiency and mechanism of various pollutants using the BEF-O reactor were investigated. The BEF-O system with the current density of 100 mA/cm² shows excellent treatment efficiency, which can roundly remove most pollutants (NH₄⁺-N, COD and heavy metals, etc.), and increase the bioavailability of the effluent to facilitate subsequent EBR treatment. Benefiting from the metabolic stimulation and population selection effect of electric current on microorganisms, EBR has a denser biofilm, stronger anti-pollution load capacity, superior, and stable pollution treatment efficiency. More importantly, the combined device can reduce the concentrations of COD and NH₄⁺-N from 6410 to 338 mg/L and 4065 to 4 mg/L, respectively, and has an economical energy consumption of 32.02 kWh/(kg COD) and 54.04 kWh/ (kg NH₄⁺-N). To summarize, this research could provide an innovative and industrial application prospect technology for the mature landfill leachate treatment.

Mechanistic investigation into flow-through electrochemical oxidation of sulfanilamide for groundwater using a graphite anode

The technical effectiveness/merit of electrochemical oxidation (EO) has been recognized. Nonetheless, its practical application to groundwater remediation has not been fully implemented due to several technical challenges. To overcome the technical incompleteness, this study adopted a graphite anode in the flow-through system and studied the mechanistic roles of a graphite anode. To this end, groundwater contaminated with sulfanilamide was remediated by means of EO, and sulfanilamide oxidation was quantitatively determined in this study. Approximately 60% of sulfanilamide was degraded at the anode zone, and such observation offered that the removal of sulfanilamide was not closely related with current variations (10-100 mA). However, this study delineated that sulfanilamide removal is contingent on the flow speed. For example, the removal of sulfanilamide was lowered from 59 to 25% owing to a short contact time when the flow velocity was increased from 0.14 to 0.55 cm/min. This study also delineated that a shorter anode-cathode distance could offer a favorable chance to enhance the removal of sulfanilamide even under an identical current. A shorter distance could offer a chance to save energy due to the lower voltage operation. This study also offered that chloride (Cl^-) and sulfate (SO₄^2-) electrolytes served a crucial role in the generation of active species. In contrast, bicarbonate (HCO₃^-) and synthetic groundwater electrolytes impeded the oxidation rate because HCO₃^- scavenged the other active species. In an effort to seek the oxidation mechanisms of a graphite anode, scavenger, cyclic voltammetry test, and electron https://en.wikipedia.org/wiki/Electron_paramagnetic_resonanceparamagnetic resonance (EPR) analysis were done. From a series of the tests, it was inferred that a graphite anode did not directly affect the generation of the active species. Thus, the prevalence of the oxygenated functional groups on an anode surface could be the main mechanism in sulfanilamide removal due to the enhanced electron transfer.

A Case Study of Swine Wastewater Treatment via Electrochemical Oxidation by Ti4O7 Anode

With the rapid development of breeding industry, the efficient treatment of dramatically increasing swine wastewater is gradually becoming urgent. In particular, the development of application technologies suitable for the relatively small piggeries is critical due to the time cost and space requirements of conventional biological methods. In this study, Electrochemical oxidation (EO) was selected to systematically explore the treatment performance of three different swine wastewaters by Ti₄O₇ anode. It was observed that the colors changed from dark brown to light yellow after 60 min treatment at 50 mA/cm², and the removal rates of turbidity and suspended solids ranged from 89.36% to 93.65% and 81.31% to 92.55%, respectively. The chemical oxygen demand (COD), ammonia nitrogen (NH₃-N) and total phosphorus (TP) of all the three swine wastewaters were simultaneously removed to a very low concentration in 120 min, especially for sample III, 61 ± 9 mg/L of COD, 6.6 ± 0.4 mg/L of NH₃-N and 5.7 ± 1.1 mg/L of TP, which met the Discharge Standard of Pollutants for Livestock and Poultry Breeding (GB 18596-2001). Moreover, 70.93%-85.37% mineralization rates were also achieved in 120 min, confirming that EO treatment by Ti₄O₇ could efficiently remove the organic matters in wastewater. Excitation-emission matrix (EEM) and UV-vis spectrum characterization results further proved that aromatic compounds and macromolecules in wastewater were rapidly removed, which played important roles in the mineralization processes. The findings here provided an efficient and environment-friendly technology for swine wastewater treatment.

Energy-efficient removal of trace antibiotics from low-conductivity water using a Ti4O7 reactive electrochemical ceramic membrane: Matrix effects and implications for byproduct formation

The inevitably high energy consumption of traditional electrochemical processes to treat low-conductivity water has limited their wider application. Herein, we present an energy-efficient alternative, i.e., a Ti₄O₇ reactive electrochemical ceramic membrane (Ti₄O₇-REM) system with a superior mass transfer ability. For the removal of 10-200 μM norfloxacin (NOR) from low-conductivity (178-832 μS cm^-1) water, the Ti₄O₇-REM system increased the kinetics rate constant by 4.3-34.0 times, thus decreasing the energy cost by 80.5-97.3% compared with a flow-by system. The rapid NOR removal was related to the enhanced direct electron transfer process in the Ti₄O₇-REM system, which allowed for higher resistance to HCO₃^- scavenging and a favorable reaction between NOR and the active sites. Meanwhile, this mechanism likely contributed to the less formation of inorganic chlorinated product, ClO₃^-, in the presence of Cl^-. Although organic chlorinated byproducts were not detected during NOR degradation in the Ti₄O₇-REM system, Cl^- influenced the speciation of the intermediates. A single-pass Ti₄O₇-REM system demonstrated 94-97% removal of trace antibiotics from real water samples in 30 s. The additional energy consumption (<0.02 kWh m^-3) using a Ti₄O₇-REM system only contributed to 5.0-6.4% of the total in a typical tertiary wastewater treatment plant. Based on the above results, we can conclude that the convection-enhanced REM technique is viable for the purification of low-conductivity natural waters.

Progress in Preparation and Application of Titanium Sub-Oxides Electrode in Electrocatalytic Degradation for Wastewater Treatment

To achieve low-carbon and sustainable development it is imperative to explore water treatment technologies in a carbon-neutral model. Because of its advantages of high efficiency, low consumption, and no secondary pollution, electrocatalytic oxidation technology has attracted increasing attention in tackling the challenges of organic wastewater treatment. The performance of an electrocatalytic oxidation system depends mainly on the properties of electrodes materials. Compared with the instability of graphite electrodes, the high expenditure of noble metal electrodes and boron-doped diamond electrodes, and the hidden dangers of titanium-based metal oxide electrodes, a titanium sub-oxide material has been characterized as an ideal choice of anode material due to its unique crystal and electronic structure, including high conductivity, decent catalytic activity, intense physical and chemical stability, corrosion resistance, low cost, and long service life, etc. This paper systematically reviews the electrode preparation technology of Magnéli phase titanium sub-oxide and its research progress in the electrochemical advanced oxidation treatment of organic wastewater in recent years, with technical difficulties highlighted. Future research directions are further proposed in process optimization, material modification, and application expansion. It is worth noting that Magnéli phase titanium sub-oxides have played very important roles in organic degradation. There is no doubt that titanium sub-oxides will become indispensable materials in the future.

Research trends in the development of anodes for electrochemical oxidation of wastewater

The review focuses on the recent development in anode materials and their synthesis approach, focusing on their compatibility for treating actual industrial wastewater, improving selectivity, electrocatalytic activity, stability at higher concentration, and thereby reducing the mineralization cost for organic pollutant degradation. The advancement in sol–gel technique, including the Pechini method, is discussed in the first section. A separate discussion related to the selection of the electrodeposition method and its deciding parameters is also included. Furthermore, the effect of using advanced heating approaches, including microwave and laser deposition synthesis, is also discussed. Next, a separate discussion is provided on using different types of anode materials and their effect on active •OH radical generation, activity, and electrode stability in direct and indirect oxidation and future aspects. The effect of using different synthesis approaches, additives, and doping is discussed separately for each anode. Graphene, carbon nanotubes (CNTs), and metal doping enhance the number of active sites, electrochemical activity, and mineralization current efficiency (MCE) of the anode. While, microwave or laser heating approaches were proved to be an effective, cheaper, and fast alternative to conventional heating. The electrodeposition and nonaqueous solvent synthesis were convenient and environment-friendly techniques for conductive metallic and polymeric film deposition.

Evaluation of diclofenac degradation effect in "active" and "non-active" anodes: A new consideration about mineralization inclination

This work investigates the electrochemical oxidation (EO) of diclofenac (DCF) in water with Ti/Ti₄O₇, Ti/Ru-Ir, Ti/Sb-SnO₂ and Ti/PbO₂ electrodes. Scanning electron microscope and X-ray diffraction results suggest that Ti/Ti₄O₇ has porous stacked surface morphology and Ti/Sb-SnO₂ possesses the smallest grain size. Linear sweep voltammetry test results indicate that PbO₂ has the highest oxygen evolution potential, while Ti/Ti₄O₇ and Ti/Ru-Ir show better oxygen evolution activity. DCF degradation results reveal that PbO₂ possessed the highest DCF removal (R_DCF = 99.2%) and chemical oxygen demand (COD) removal (R_COD = 97.0%), the fastest COD degradation rate (k = 0.0275 min^-1, R² = 0.964), the lowest specific energy consumption (EC_DCF = 1.81 kWh^.g DCF^-1, EC_TOC = 6.90 kWh^.g TOC^-1). The toxicity variation of DCF during EO process on PbO₂ is rise first and then to fall. Considering the differences of the four electrodes in residual, conversion and mineralization aspects, mineralization selectivity (MS) was proposed to estimate the mineralization inclination of electrodes during EO process, and PbO₂ displays the strongest mineralization inclination (MS = 0.594). In addition, the possible degradation pathway of DCF on PbO₂ electrode indicates a composite behavior of conversion and mineralization. All of them above indicate the promising application potential of PbO₂ in lower concentration pharmaceuticals and personal care products wastewater treatment. Moreover, MS could be employed as a supplementary index to assess the different inclinations of this composite behavior on various electrodes used for electrochemical treatment of organics in later studies.

Decolorization of textile wastewater by electrooxidation process using different anode materials: Statistical optimization

The presence of reactive dyes in textile wastewater is a serious environmental concern due to their associated mutagenic and carcinogenic effects. The present study aims to analyze the effect of different anodic materials on the decolorization of a real textile wastewater effluent. For this purpose, four different anodic materials-TiO2 -coated platine, TiO2 -coated ruthenium dioxide (RuO2 ) (viz., RuO2 ), titanium dioxide (TiO2 ), and graphite-were connected, respectively, to titanium dioxide (TiO2 ) used as a cathode electrode. Color and cost optimization studies were performed using the response surface methodology and the Box-Behnken experimental design (BBD). According to ANOVA results, the R2 values for Pt/TiO2 , RuO2 /TiO2 , TiO2 /TiO2 , and graphite/TiO2 electrode pairs were found to be 97.4%, 93.8%, 92.44%, and 92.2%, respectively, indicating a good compatibility as it is close to one. The results show that color removal efficiencies at the optimal conditions were 86.3%, 90.8%, 91.5%, and 93.6% for Pt/TiO2 , graphite/TiO2 , TiO2 /TiO2 , and RuO2 /TiO2 , respectively. Furthermore, energy consumption cost at the optimum conditions was also evaluated, and the results were as follows: Pt/TiO2 (0.95 €/m3 ), graphite/TiO2 (0.74 €/m3 ), TiO2 /TiO2 (0.31 €/m3 ), and RuO2 /TiO2 (0.26 €/m3 ). Consequently, this research paper shows that all of the tested anodic materials give satisfactory color removal efficiencies higher than 86%. When energy consumption and color removal are considered together, the use of TiO2 /TiO2 and RuO2 /TiO2 pairs would be preferred. PRACTITIONER POINTS: Anodic contribution was investigated for decolorization of textile wastewater by electrooxidation process. Graphite, TiO2 -coated Pt, TiO2 -coated RuO2 , and TiO2 were used as anode materials. Highest color removal with lowest energy consumption was achieved with TiO2 -coated RuO2 anode material (93.6%).

Current progress in electrochemical anodic-oxidation of pharmaceuticals: Mechanisms, influencing factors, and new technique

Various pharmaceuticals have been detected in natural water and wastewater bodies, causing threats to water ecosystem and human health. Although electrochemical anodic-oxidation (EAO) has been shown to be efficient for pharmaceuticals degradation from aqueous solution, it still has a distinct need to apply EAO technology for pharmaceuticals removal rationally. This review provides the most recent progress on the mechanisms, influencing factors, and new technique of EAO for pharmaceuticals degradation. The mechanism and superiority of EAO were analyzed. Major influencing factors (e.g., electrode materials, electrochemical reactor, applied current density, anode-cathode distance, electrolyte type and concentration, initial solution pH value, and initial pharmaceuticals concentration) were discussed on the removal of pharmaceuticals. The latest development of reactive electrochemical membranes (REM) was regarded as an emerging EAO technique, and it was also highlighted. This work revealed that the EAO of pharmaceuticals has extraordinary application prospects in the field of water and wastewater treatment.

Mechanism of N,N-dimethylformamide electrochemical oxidation using a Ti/RuO2-IrO2 electrode

The compound N,N-dimethylformamide (DMF) is a widely used industrial chemical and a common environmental contaminant that has been found to be harmful to human health. In this study, electrochemical oxidation was adopted for the degradation of DMF. The effects of four kinds of electrodes on the removal rates of DMF and total organic carbon were compared, and based on the result, the Ti/RuO₂–IrO₂ electrode was selected as the operating electrode. The effects of three independent factors (current density, pH, and NaCl proportion) on the DMF degradation were investigated through single-factor experiments, and the experimental results were optimized by response surface methodology. The optimal experimental conditions were obtained as follows: current density = 47 mA cm⁻², pH = 5.5, and NaCl proportion = 15%. The electrochemical oxidation of 50 mg L⁻¹ DMF was performed under the optimal conditions; the degradation rate was 97.2% after 7 h, and the reaction followed the pseudo-first-order kinetic model. The degradation products under optimal conditions and chlorine-free conditions were analyzed, and four degradation pathways were proposed. The DMF degradation was more thorough under optimal conditions.

DEMS as an emerging technology was used to investigate the degradation mechanism of DMF.