Degradation of levofloxacin in wastewater by photoelectric and ultrasonic synergy with TiO2/g-C3N4@AC combined electrode.

A novel particle combined electrode named TiO2/g-C3N4@AC (TGCN-AC) was prepared by loading TiO2 and g-C3N4 on activated carbon through gel method, which was used to degrade levofloxacin (LEF) in pharmaceutical wastewater by photoelectric process. The remarkable physicochemical features of particle electrodes were verified by using diverse characterization techniques including SEM-EDS, XRD, FT-IR, BET and pHZPC. EIS-CV and photocurrent showed excellent electrocatalysis and photoelectrocatalysis performance of particle electrodes. The photocatalytic characteristics and fluorescence properties of the particle electrode were proved by UV-vis DRS and PL spectra measurements. Combined with Tauc's plot and Mott-Schottky plots curves, the ECB and EVB of particle electrodes were determined. The experiments on different influence factors such as pH, ultrasonic, aeration, current density and the concentration of LEF were carried out in the photoelectric reactor. Under the conditions of pH values 3.0, 200 W ultrasonic, 8 L/min aeration, the mass ratio of g-C3N4 and TiO2 is 8%, after 4.0 h of photoelectric process, about 94.76% of LEF (20 mg/L) in water was degraded. TGCN-AC also has excellent reusability. The degradation rate of LEF can still reach 71.17% after repeated use for 6 times. Scavenger studies showed that h+ and O2- were the main active species. By observing the colony size of E. coli, it was proved that the LEF in the effluent had no antibacterial activity. The degradation pathways of LEF was analyzed and drawn by HPLC-MS spectra.

An overview of recent advances and future prospects of three-dimensional biofilm electrode reactors (3D-BERs).

Three-dimensional biofilm electrode reactors (3D-BERs) have attracted extensive attention in recent years due to their wide application range, high efficiency and energy saving. On the basis of traditional bio-electrochemical reactor, 3D-BERs are filled with particle electrodes, also known as the third electrodes, which can not only be used as a carrier for microbial growth, but also improve the electron transfer rate of the whole system. This paper reviews the constitution, advantages and basic principles of 3D-BERs as well as current research status and progress of 3D-BERs in recent years. The selection of electrode materials, including cathode, anode and particle electrode are listed and analyzed. Different constructions of reactors, like 3D-unipolar extended reactor and coupled 3D-BERs are introduced and discussed. Various contaminants degraded by 3D-BERs including nitrogen, azo dyes, antibiotics and the others are calculated and the corresponding degradation effects are described. The influencing factors and mechanisms are also introduced. At the same time, according to the research advances of 3D-BERs, the shortcomings and weakness of this technology in the current research process are analyzed, and the future research direction of this technology is prospected. This review aims to summarize recent studies of 3D-BERs in bio-electrochemical reaction and open a bright window to this booming research theme.

Insight into the Fe-Ni/biochar composite supported three-dimensional electro-Fenton removal of electronic industry wastewater.

For the efficient removal of the bio-refractory organic pollutants in the electronic industry wastewater, the Ni-Fe (oxides) modified three-dimension (3D) particle electrode was applied in electro-Fenton system (3D/EF), where iron ions were released from anode and deposited onto algal biochar (ABC) to prepare composite catalyst during reaction process. Firstly, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis were applied to confirm successful fabrication of the 3D particle electrode materials. Secondly, COD removal efficiency could reach about 80%, which was about 20% higher than that in 2D/EF system, under the optimized conditions as 2.0 g/L of Ni-ABC particle electrodes, initial pH of 3, 100 mL/min of aeration intensity and 20 mA/cm2 of applied current density. Thirdly, characterized using three-dimensional fluorescence spectroscopy and GC-MS analysis, it seemed that most of the macromolecular substances could be degraded, whereas mono-2-ethylhexyl phthalate (MEHP) was identified as the most abundant and representative compound. Finally, possible degradation pathway of MEHP in 3D/EF system was proposed including dealkylation, cleavage of C-O bond, and demethylation. Therefore, this study provides a new strategy in designing EF system employing bimetal doped biochar composite for an efficient elimination of organic pollutants within electronic industry wastewater.

Decomplexation of Cu-1-hydroxyethylidene-1,1-diphosphonic acid by a three-dimensional electrolysis system with activated biochar as particle electrodes.

The feasibility of decomplexation removal of typical contaminants in electroplating wastewater, complexed Cu(II) with 1-hydroxyethylidene-1,1-diphosphonic acid (Cu-HEDP), was first performed by a three-dimensional electrode reactor with activated biochar as particle electrodes. For the case of 50 mg/L Cu-HEDP, Cu(II) removal (90.7%) and PO43- conversion (34.9%) were achieved under the conditions of electric current 40 mA, initial pH 7, acid-treated almond shell biochar (AASB) addition 20 g/L, and reaction time 180 min, with second-order rate constants of 1.10 × 10-3 and 1.94 × 10-5 min-1 respectively. The growing chelating effect between Cu(II) and HEDP and the comprehensive actions of adsorptive accumulation, direct and indirect oxidation given by particle electrodes accounted for the enhanced removal of Cu-HEDP, even though the mineralization of HEDP was mainly dependent on anode oxidation. The performance attenuation of AASB particle electrodes was ascribed to the excessive consumption of oxygen-containing functionalities during the reaction, especially acidic carboxylic groups and quinones on particle electrodes, which decreased from 446.74 to 291.48 µmol/g, and 377.55 to 247.71 µmol/g, respectively. Based on the determination of adsorption behavior and indirect electrochemical oxidation mediated by in situ electrogenerated H2O2 and reactive oxygen species (e.g., •OH), a possible removal mechanism of Cu-HEDP by three-dimensional electrolysis was further proposed.

High efficiency three-dimensional electrochemical treatment of amoxicillin wastewater using Mn-Co/GAC particle electrodes and optimization of operating condition.

In this work, Mn-Co/GAC particle electrode was prepared by loading Mn and Co as catalysts on granular activated carbon (GAC) and used in a three-dimensional (3D) electrochemical system for mineralization of amoxicillin wastewater. Observation results by SEM, EDS and XRD confirmed that Mn and Co catalysts were successfully loaded onto GAC. The electrochemical properties were measured using an electrochemical workstation. Mn-Co/GAC had a much higher oxygen evolution potential (1.46V) than GAC (1.1V), which demonstrated that it could effectively reduce the oxygen evolution side reaction. In addition, Mn-Co/GAC had an electrochemically active surface area 1.34 times that of GAC and a much smaller mass transfer resistance than GAC, which could provide favorable conditions for the degradation of pollutants. The investigation of the influences of single operating parameters on total organic carbon (TOC) removal rate and electrical energy consumption (EEC) indicated that current density and treatment time had the greatest effect. In order to maximize TOC removal rate and minimize EEC, optimization of operating parameters was also carried out using response surface method in combination with central composite design. The optimal operating parameters were determined as current density of 5.68 mA/cm2, electrolyte concentration of 0.127M, particle electrode dosage of 31.14g and treatment time of 120min. Under this optimum operating condition, TOC removal rate of 85.24% and amoxicillin removal rate of 100% could be achieved with a low EEC of 0.073 kWh/g TOC. In addition, TOC removal rate and EEC were significantly improved compared to the use of bare GAC as particle electrode under the same operating conditions, demonstrating the excellent electrocatalytic ability of the new particle electrode Mn-Co/GAC. A possible mechanism of enhanced amoxicillin and TOC removal was also recommended. In summary, the 3D electrochemical method using Mn-Co/GAC particle electrodes is a suitable choice for amoxicillin wastewater treatment.

Bimetallic modified halloysite particle electrode enhanced electrocatalytic oxidation for the degradation of sulfanilamide.

The treatment of antibiotics wastewater by electrocatalytic oxidation has attracted much attention. In the paper, a novel halloysite bimetallic (HLS-Cu-Mn) particle electrode material was prepared and a bench-scale electrocatalytic reaction tank was designed. A three-dimensional electrocatalytic oxidation reactor composed of HLS-Cu-Mn and a bench-scale electrocatalytic reaction tank was used to degrade Sulfanilamide (SA) wastewater. Characterization of the synthesized material was conducted with Scanning electron microscopy (SEM), X-ray polycrystalline powder diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The electron spin resonance spectroscopy test results confirmed that HLS-Cu-Mn produced a large number of •OH. The electrochemical workstation confirmed that HLS-Cu-Mn had strong electrocatalytic activity and repolarization ability. Under the optimum preparation conditions and degradation process parameters, the removal efficiency of SA and TOC was 99.84% and 88.95% respectively. The method also has good degradation efficiency for aniline, phenol, herbicides, antibiotics, and dyeing wastewater. It was found that 4 main intermediates appeared in the degradation process by Ultra-high performance liquid chromatography/triple tandem quadrupole mass spectrometry (LC-MS). In sum, it was believed that this work provides a new vision and idea for water treatment.

Hydroxyapatite nanoparticle functionalized activated carbon particle electrode that removes strontium from spiked soils in a unipolar three-dimensional electrokinetic system.

Biohazard performance of Sr radionuclide can be significantly magnified by its release from the contaminated sedimentation. In this study, hydroxyapatite nanoparticle-functionalized activated carbon electrode (AC-HAP) was synthesized and stacked to the cathode compartment of the electrokinetic (EK) system to develop a unipolar three-dimensional (3D) electrochemical process for Sr2+ removal from spiked soils. Sr2+ adsorption by AC-HAP can be fitted by the pseudo-first-order and pseudo-second-order kinetic models and the Langmuir, Freundlich, and Temkin isotherm models. The largest monolayer adsorption capacity of AC-HAP of 69.49 mg g-1 was evaluated in the pH range of 10-12 and at 40 °C. 3D EK further intensified the adsorption process of AC-HAP and the corresponding Sr2+ removal from aqueous environments. Voltage gradients and proposing time had a significant effect on the migration and transmission of Sr2+ in the electrolyzer. The influence of competitive ions on Sr2+ removal in the stock solutions followed Al3+ < Mg2+ < K+ < Na+ < Ca2+ while followed Al3+ < Na+ < K+ < Mg2+ < Ca2+ in 3D EK. The first three cycles for AC-HAP had taken roughly 50% of the reusability percentage. Sr2+ removal from spiked samples in 3D EK was achieved by acid dissolution, electromigration, and selective uptake on particle electrode.

Electrochemical degradation of oxytetracycline by Ti-Sn-Sb/γ-Al2O3 three-dimensional electrodes.

In this work, Ti-Sn-Sb/γ-Al2O3 particle electrodes were prepared and employed for the degradation of oxytetracycline (OTC) by three-dimensional electrocatalytic technology. Factors associated with the preparation of Ti-Sn-Sb/γ-Al2O3 particle electrodes were investigated. The effects of initial concentration, conductivity, pH value, aeration intensity, current density, plate spacing, and particle electrode dosage on OTC removal were studied. The removal rate of OTC and total organic carbon were achieved approximately 92.0% and 41.0% under the optimal operating condition, respectively. In addition, Ti-Sn-Sb/γ-Al2O3 particle electrode was analyzed by Fourier Transform Infrared spectroscopy (FT-IR), scanning electron microscope (SEM), energy dispersive spectrum analysis (EDX), X-Ray Fluorescence Spectrometer (XRF), and X Ray Diffraction analysis (XRD), which indicated that a significant amount of TiO2, SnO2, and Sb2O3 were formed on the surface of Ti-Sn-Sb/γ-Al2O3 particle electrode. It was also observed that the primary function of Ti-Sn-Sb/γ-Al2O3 particle electrode in the three-dimensional electrode electrolysis process is the strong oxidizing function of ·OH for degrading OTC. Consequently, the analysis of degradation products of oxytetracycline (OTC) demonstrates. In addition, the results and conclusions of this study provide a methodological basis and engineering practice basis for removing the low concentration of antibiotics in water.

Advances in three-dimensional electrochemical degradation: A comprehensive review on pharmaceutical pollutants removal from aqueous solution.

Water pollution, stemming from various contaminants including organic and pharmaceutical pollutants, poses a significant global challenge. Amidst the array of methods available for pollutant mitigation, the three-dimensional electrochemical approach emerges as a standout solution due to its environmental compatibility, cost-effectiveness, and rapid efficiency. This study delves into the efficacy of three-dimensional electrochemical processes in purging organic and pharmaceutical pollutants from aqueous media. Existing research indicates that the three-dimensional electrochemical process, particularly when employing particle electrodes, exhibits notable success in degrading organic and pharmaceutical pollutants. This achievement is largely attributed to the ample specific surface area of particle electrodes and the shortened mass transfer distance, which collectively enhance efficiency in comparison to traditional two-dimensional electrochemical methods. Moreover, this approach is lauded for its environmental friendliness and cost-effectiveness. However, it is imperative to note that the efficacy of the process is subject to various factors including temperature, pH levels, and current intensity. While the addition of oxidants can augment process efficiency, it also carries the risk of generating intermediate compounds that impede the reaction. In conclusion, the three-dimensional electrochemical method proves to be a viable and practical approach, provided that process conditions are meticulously considered and adhered to. Offering advantages from both environmental and economic perspectives, this method presents a promising alternative to conventional water and wastewater treatment techniques.

A new attempt to remove toluene using nickel-iron bimetallic particle electrode reactor.

A new attempt of removing toluene waste gas using a three-dimensional electrode reaction device with nickel-iron bimetallic particle electrode is presented in this paper. The particle electrode was prepared by a simple liquid phase reduction method. Through bimetal modification, the particle electrode mass transfer rate is increased to 1.29 times, and the degradation efficiency of the reactor is increased by nearly 40%, which makes it possible to remove toluene waste gas by other electrochemical methods in addition to plasma method. The removal efficiency of the particle electrode can be stabilized at more than 80% after 5 cycles (50 h). At the same time, the relationship between independent working parameters and dependent variables is analyzed using the central composite design, and the operating parameters are optimized. Based on this study, the removal mechanism and possible degradation pathway of toluene were investigated. This study provides a supplement to the possibility and theoretical basis of new technology application for electrocatalytic oxidation removal of VOCs.

MXene-based composite aerogels with bifunctional ferrous ions for the efficient degradation of phenol from wastewater.

Herein, MXene-based composite aerogel (MXene-Fe2+ aerogel) are constructed by a one-step freeze-drying method, using Ti3C2Tx MXene layers as substrate material and ferrous ion (Fe2+) as crosslinking agent. With the aid of the Fe2+ induced Fenton reaction, the synthesized aerogels are used as the particle electrodes to remove phenol from wastewater with three-dimensional electrode technology. Combined with the dual roles of Fe2+ and the highly conductive MXene, the obtained particle electrode possesses extremely effective phenol degradation. The effects of experiment parameters such as Fe2+ to MXene ratio, particle electrode dosage, applied voltage, and initial pH of solution on the removal of phenol are discussed. At pH = 2.5, phenol with 50 mg/L of initial concentration can be completely removed within 50 min at 10 V with the particle electrode dosage of 0.56 g/L. Finally, the mechanism of degradation is explored. This work provides an effective way for phenol degradation by MXene-based aerogel, which has great potential for the degradation of other organic pollutants in wastewater.

Electrocatalytic denitrification biofilter for advanced purification of chlorophenols via ceramsite-based Ti/SnO2-Sb particle electrode: Performance, microbial community structure and mechanism.

In response to the demand for advanced purification of industrial secondary effluent, a new method has been developed for treating chlorophenol wastewater using the novel ceramsite-based Ti/SnO2-Sb particle electrodes (Ti/SnO2-Sb/CB) enhanced electrocatalytic denitrification biofilter (EDNBF-P) to achieve removal of chlorophenols (CPs), denitrification, and reduction of effluent toxicity. The results showed that significantly improved CPs and TN removal efficiency at low COD/N compared to conventional denitrification biofilter, with CPs removal rates increasing by 0.33%-59.27% and TN removal rates increasing by 12.53%-38.92%. Under the conditions of HRT = 2h, 3V voltage, charging times = 12h, and 25 °C, the concentrations of the CPs in the effluent of EDNBF-P were all below 1 mg/L, the TN concentration was below 15 mg/L, while the effluent toxicity reached the low toxicity level. Additionally, the Ti/SnO2-Sb/CB particle electrodes effectively alleviated the accumulation of NO2--N caused by applied voltage. The Silanimonas, Pseudomonas and Rhodobacter was identified as the core microorganism for denitrification and toxicity reduction. This study validated that EDNBF-P could achieve synergistic treatment of CPs and TN through electrocatalysis and microbial degradation, providing a methodological support for achieving advanced purification of chlorophenol wastewater with low COD/N in industrial applications.

Efficient degradation of N-nitrosopyrrolidine using CoFe-LDH/AC particle electrode via heterogeneous Fenton-like reaction.

With the rapid development of drinking water disinfection technology, extensive attentions are paid to the nitrogenous disinfection by-products (N-DBPs) that has strong carcinogenicity, thus their degradation becomes important for the health of human beings. In this work, for the first time, CoFe-LDH material used as particle electrode is proposed to treat trace N-nitrosopyrrolidine (NPYR) in a three-dimensional aeration electrocatalysis reactor (3DAER). The factors on the degradation efficiency and energy consumption of NPYR are systematically investigated, and the results of radical quenching experiments show that the degradation of NPYR is completed by combining with ·OH, ·O2and direct oxidation together. CoFe-LDH particle electrode plays a vital role in generating ·OH via heterogeneous ‾Fenton-like reaction. Moreover, the adsorbed saturated CoFe-LDH particle electrode can be regenerated by electrochemical action to induce further recycle adsorption and form in-situ electrocatalysis. This work pave a way for the removal of NPYR with high efficiency, low energy conservation and environmental protection.

Heterogeneous electro-Fenton using three-dimension Fe-Co-Bi/kaolin particle electrodes for degradation of quinoline in wastewater.

Wastewater containing quinoline has become a common pollutant in water and soil environments, which poses a threat to human health due to its carcinogenicity, teratogenicity, and mutagenicity. Quinoline's stability and toxicity hinders its degradation by conventional physicochemical and biological methods. In this contribution, Fe-Co-Bi/kaolin particle electrodes were prepared for the efficient degradation of quinoline in wastewater, and characterized by using scanning electron microscope, X-ray diffraction, pyridine-IR, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and four-probe resistivity test. Parameters affecting the degradation efficiency were optimized to be the particle electrode dosage of 40 g/L, pH 3.5, H2O2 addition of 67.6 mmol/L, electrical conductivity of 12.7 ms/cm, and voltage of 20 V. The constructed three-dimensional catalytic particle electrode system (3D-CPE) achieved 92.1% removal rate of chemical oxygen demand (COD) under the optimal conditions. Hydroxyl radicals (•OH) generated in the 3D-CPE process were identified by radical scavenging tests and electron spin response analysis. To unravel the degradation mechanism, the intermediate products were identified by using high performance liquid chromatography-mass spectrometry. The degradation mechanism was discussed with the help of theoretical calculation.

Three-dimensional electro-Fenton system supplied with a nanocomposite of microbial cellulose/Fe3O4 for effective degradation of tetracycline.

In this study, the catalytic activity of the modified microbial cellulose/Fe3O4 (MMC/ Fe3O4) composite was studied for tetracycline (TC) degradation and mineralization in a three-dimensional electro-Fenton system (3D-EF). The MC/Fe3O4 was modified at 400 °C for 60 min. The MMC/ Fe3O4 was fully analyzed (morphological, structural, chemical properties). Complete degradation and 65% mineralization of TC was achieved in the 3D-EF process (0.5 g L-1 MMC/ Fe3O4, 10 mM NaCl electrolyte, and neutral pH) within 20 min and electrical energy consumption (EEC) 0.86 kwh g-1 TC under the 6.66 mA cm-2. High degradation efficiency TC, in 3D-EF system was attributed to significant single oxygen (1O2), superoxide(O2•-) participation and less to Hydroxyl radical (OH•). Reusability of the MMC/ Fe3O4 was successfully carried out for five consecutive runs. Accordingly, greencompositeof MMC/ Fe3O4 can be considered as an efficient and durable particle electrode (PE) to degrade and mineralize emerging pollutants in an aquatic environment.

Cerium added corn-based biochar as particle electrode for electrochemical oxidation industrial wastewater.

Three-dimensional (3D) electrochemical oxidation has become a popular advanced oxidation technology for wastewater treatment due to its various benefits. In this study, cerium (Ce) loaded biochar (Ce/BC) was used as a particle electrode to conduct the degradation of industrial wastewater released by the chemical industry. SEM, EDS, XRD, FTIR, XPS, and BET were used to characterize the properties of Ce/BC. The effects of some variables, including Ce loading (0-5%), pH (5-9), Ce/BC dosage (12.5-50.0 g/L), and working voltage (12-20 V), were evaluated with regard to COD elimination. The kinetics of COD oxidation and the energy consumption were carefully investigated. Tert-butanol significantly reduced the removal efficiency of COD, indicating that hydroxyl radicals generated during the process rather than direct electro-oxidation were the main mechanism for COD degradation. The treatment of industrial wastewater might benefit from the use of Ce/BC as particle electrode.

Preparation of SnO2-Sb/attapulgite (AP) clay particulate electrode for efficient phenol electrochemical oxidation.

A novel SnO2-Sb/AP (attapulgite) particle electrode was prepared for three-dimensional electrocatalytic oxidation (3D/EO) of organic pollutants using a co-sintering method. The electrochemical properties and micromorphology were determined using polarization, cyclic voltammetry (CV), and field emission scanning electron microscope (FE-SEM), and compared with activated carbon (AC), AP, and TiO2/AP particle electrodes. Besides, their potential application in the electrochemical degradation of phenol was investigated. The SnO2-Sb/AP particle electrode exhibited higher electrochemical activity than other particle electrodes due to its large number of active sites, low transfer coefficient (α, 0.12), and high-volt ampere charge (q*, 1.18 C·cm-2). The electrochemical CODCr degradation efficiency (100%) of phenol on SnO2-Sb/AP particle electrodes is much higher than for other particle electrodes. Moreover, an excellent stability of the SnO2-Sb/AP particle electrode is also verified by repeated experiments. These results indicate that the SnO2-Sb/AP particle electrodes broaden the application area of clays and are expected to be a promising method for 3D/EO.

Fluidized ZnO@BCFPs Particle Electrodes for Efficient Degradation and Detoxification of Metronidazole in 3D Electro-Peroxone Process.

A novel material of self-shaped ZnO-embedded biomass carbon foam pellets (ZnO@BCFPs) was successfully synthesized and used as fluidized particle electrodes in three-dimensional (3D) electro-peroxone systems for metronidazole degradation. Compared with 3D and 2D + O3 systems, the energy consumption was greatly reduced and the removal efficiencies of metronidazole were improved in the 3D + O3 system. The degradation rate constants increased from 0.0369 min-1 and 0.0337 min-1 to 0.0553 min-1, respectively. The removal efficiencies of metronidazole and total organic carbon reached 100% and 50.5% within 60 min under optimal conditions. It indicated that adding ZnO@BCFPs particle electrodes was beneficial to simultaneous adsorption and degradation of metronidazole due to improving mass transfer of metronidazole and forming numerous tiny electrolytic cells. In addition, the process of metronidazole degradation in 3D electro-peroxone systems involved hydroxyethyl cleavage, hydroxylation, nitro-reduction, N-denitrification and ring-opening. The active species of ·OH and ·O2- played an important role. Furthermore, the acute toxicity LD50 and the bioconcentration factor of intermediate products decreased with the increasing reaction time.

Removal of Ammonia Using Persulfate during the Nitrate Electro-Reduction Process.

NH4+ is often produced during the electro-reduction of NO3-, which results in inadequate total nitrogen (TN) removal during advanced sewage treatment. In this study, the electro-reduction byproduct NH4+ was oxidized and removed using sulfate radical (SO4•-)-based advanced oxidation. Persulfate (PS) was activated by electrocatalysis, using Co/AC0.9-AB0.1 particle electrodes to produce SO4•-. Results showed that when the influent concentration of NO3--N was 20 mg/L, a PS dosage of 5.0 mM could completely oxidize NH4+ at 0.1 A (nondetectable in effluent) reducing the TN concentration from 9.22 to 0.55 mg/L. The presence of coexisting PO43-, CO32- and humic acid suppressed the oxidation and removal of NH4+. Electron spin resonance (ESR) spectra and quenching experiments revealed SO4•- as the dominant radical in the process of indirect NH4+ oxidation, while •OH radicals only had an assisting role, and the surface accumulated free radicals were responsible for the indirect oxidation of NH4+. Cyclic voltammetry (CV) curves indicated that NO3- was primarily reduced via atomic H*-mediated indirect reduction. Therefore, the activation of PS using Co/AC0.9-AB0.1 particle electrodes might be a promising alternative method for oxidizing byproduct NH4+ in the electro-reduction of NO3- and reduce TN concentration in advanced sewage treatment.

Electrocatalytic degradation of sulfamethylthiadiazole by GAC@Ni/Fe three-dimensional particle electrode.

In this work, GAC@Ni/Fe particle electrodes were prepared and employed for the degradation of sulfamethylthiadiazole (SMT) by three-dimensional electrocatalytic technology. The effects of particle electrode bi-metal loading ratio, cell voltage, particle electrode dosage, electrode plate spacing, and SMT initial concentration on SMT removal were studied. In addition, GAC@Ni/Fe particle electrode was analyzed by the scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), and Fourier transform infrared spectrometer (FTIR) to characterize which indicated that a significant amount of iron-nickel oxide was formed on the surface of GAC@Ni/Fe particle electrode. The results indicated that when the nickel-iron loading ratio is 1:1, the SMT removal effect is the best, and the removal rate can reach 90.89% within 30 min. Compared with the granular activated carbon without bimetal, the removal efficiency is increased by 37.58%. The degradation of SMT in the GAC@Ni/Fe particle three-dimensional electrode reactor is the joint result of both direct oxidation and indirect oxidation. The contribution rates of direct oxidation of anode and particle electrode and indirect oxidation of ·OH in the degradation are 32%, 27%, and 41%, respectively. Based on the intermediate detected by ultra-high liquid chromatography and the calculation of bond energy of SMT molecule by Gauss software, the degradation pathway of SMT in the GAC@Ni/Fe three-dimensional electrode reactor is proposed. This research provides a green, healthy, and effective method for removing sulfonamide micro-polluted wastewater.