electro-Fenton Process Research Articles

Photocatalysis coupled electro-Fenton process for treatment of acrylamide wastewater: an optimised study

ABSTRACT Electro-Fenton is a commonly used approach for pollutant removal from different wastewater that requires high energy consumption. Coupling electro-Fenton with solar energy could potentially overcome high power consumption. Thus, this study combined photocatalysis with three-dimensional electro-Fenton to treat acrylamide (AM) wastewater. The removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH3−N), and total organic carbon (TOC) in photocatalysis-coupled electro-Fenton were studied. The effects of current density, iron powder dosage, plate spacing, and photocatalyst dosage on COD and NH3−N removal were also optimised using response surface methodology (RSM). The photocatalysis coupled three-dimensional electro-Fenton reduced energy consumption compared to single photocatalysis or electro-Fenton technology. The COD and NH3−N removal rates were 82.444% and 92.810%, respectively, at the current density of 16.000 mA/cm2, iron powder dosage of 1.330 g, plate spacing of 16.643 mm, photocatalyst dosage of 0.2 g. This study demonstrated that organic pollutants can be degraded efficiently at a low concentration of catalysts coupled with the electro-Fenton process, offering a low-energy consumption treatment of wastewater.

Boosting the O2-to-H2O2 Selectivity Using Sn-Doped Carbon Electrocatalysts: Towards Highly Efficient Cathodes for Actual Water Decontamination.

The high cost and often complex synthesis procedure of new highly selective electrocatalysts (particularly those based on noble metals) for H2O2 production are daunting obstacles to penetration of this technology into the wastewater treatment market. In this work, a simple direct thermal method has been employed to synthesize Sn-doped carbon electrocatalysts, which showed an electron transfer number of 2.04 and outstanding two-electron oxygen reduction reaction (ORR) selectivity of up to 98.0 %. Physicochemical characterization revealed that this material contains 1.53 % pyrrolic nitrogen, which is beneficial for the production of H2O2, and -C≡N functional group, which is advantageous for H+ transport. Moreover, the high volume ratio of mesopores to micropores is known to favor the quick escape of H2O2 from the electrode surface, thus minimizing its further oxidation. A purpose-made gas-diffusion electrode (GDE) was prepared, yielding 20.4 mM H2O2 under optimal electrolysis conditions. The drug diphenhydramine was selected for the first time as model organic pollutant to evaluate the performance of an electrochemical advanced oxidation process. In conventional electro-Fenton process (pH 3), complete degradation was achieved in only 15 min at 10 mA cm-2, whereas at natural pH 5.9 and 33.3 mA cm-2, almost overall drug removal was reached in 120 min.

Improvement of electro-Fenton process by using heterogeneous Fe-MIL-88B nanocatalyst and simultaneous rotation of cathode and anode for dye removal

In this study, improvement of the electro-Fenton process using Fe-MIL-88B along with the innovation in the reactor with the simultaneous rotation of the cathodes and anodes was carried out to remove Acid Blue 25. For this purpose, the Fe-MIL-88B nanocatalyst was synthesised by the thermal solvent method and was characterised by FT-IR, EDAX, XRD, and FESEM. For the experiments, an electrochemical cell with a useful volume of 1 L and rotating cathodes and anodes were used and nanoparticles were added to the system as a slurry. To determine the appropriate values of the effective parameters, the OFAT method was used. According to the results, 0.3 g/L Fe-MIL-88B, pH equal to 3, dye concentration of 75 mg/L, a current intensity of 0.228 A, and a rotation velocity of 100 rpm were chosen as suitable values for the process. In optimal conditions, the dye removal efficiency reached to 92.3% after 90 min, which resulted in a 14.5% improvement in the dye removal efficiency compared to the conventional process under the same conditions. Also, after 90 min, the removal efficiencies of 77.08 and 63.63% were obtained for COD and TOC, respectively. The results indicated acceptable decomposition of the effluent into less hazardous compounds.

The Degradation of Rhodamine B by an Electro-Fenton Reactor Constructed with Gas Diffusion Electrode and Heterogeneous CuFeO@C Particles

Compared with conventional Fenton processes, the electro-Fenton process consumes fewer chemicals and produces less sludge, as it can generate the required Fenton’s reagents in situ. In this work, an electro-Fenton reactor was constructed to treat synthetic rhodamine B (Rh B) wastewater, in which a gas diffusion electrode (GDE) was used as a cathode to produce H2O2, and heterogeneous CuFeO@C particles were used to generate Fe2+ in situ. The results indicated that the gas diffusion electrode made of elements N-S-B and r-graphene oxide (NSB-r-GO) composites produced more H2O2 than the one made from r-graphene oxide (r-GO), under the conditions of 0.1 mol ·L−1 Na2SO4 electrolyte, 10 mA·cm−2 current density, and 1.0 L·min−1 O2 flow rate, with the accumulated H2O2 production reaching 105.43 mg·L−1. Additionally, different iron morphologies, including octahedral Fe (II), octahedral Fe (III), and tetrahedral Fe (III), were found in the calcined CuFeO@C particles, approximately 1.0 mg·L−1 of iron ions dissolved in the electrolyte was detected, which worked simultaneously as conductive electrodes in a conceptual three-dimensional electrochemical reactor consisting of a gas diffusion electrode cathode, Ti/RuSn anode, and CuFeO@C particle electrodes. No external Fenton reagents were necessary.

Repurposing waste-iron electrocoagulated algal biomass as effective heterogenous (bio)electro-fenton catalyst for phthalate removal from wastewater

The presence of refractory micropollutants in natural waters poses significant environmental and health risks. Preferably, advanced oxidation techniques like electro-Fenton (EF) and bio-electro-Fenton (BEF) are used to mitigate micropollutants; nevertheless, their field-scale implementation is limited by prohibitive catalyst cost. As an alternative, waste-iron electrocoagulated algal biomass (A-BC/Fe) was explored as a heterogeneous Fenton catalyst to eliminate dimethyl phthalate (DMP) from wastewater. The Fenton-conducive morphological, chemical, and electrochemical properties of the A-BC/Fe catalyst were revealed by detailed characterisation. In EF treatment, 10 mg/L of DMP was completely degraded within 15 min at pH of 7.0, 50 mM Na2SO4, and cathode potential of − 1.4 V vs. Ag/AgCl. Moreover, the EF system achieved 87.80 ± 2.10% and 96.14 ± 1.10% of DMP removal from secondary and tertiary treated municipal sewage, respectively. The A-BC/Fe catalyst-driven EF process disintegrated DMP into benign non-toxic by-products and showed stable performance over eight batch cycles with only a 1.71% decline in DMP removal efficiency. Further, the A-BC/Fe-catalysed BEF system eliminated 94.81 ± 1.90% of DMP in 4 h while achieving a maximum power density of 124.03 ± 5.64 mW/m2. This investigation underscores the potential of repurposing electrocoagulated algal biomass as a sustainable heterogenous catalyst for micropollutant remediation.

Assessment of homogeneous electro-Fenton process coupled with microbial fuel cell utilizing Serratia sp. AC-11 for glyphosate degradation in aqueous phase

Glyphosate (GLY), a globally-used organophosphate herbicide, is frequently detected in various environmental matrices, including water, prompting significant attention due to its persistence and potential ecological impacts. In light of this environmental concern, innovative remediation strategies are warranted. This study utilized Serratia sp. AC-11 isolated from a tropical peatland as a biocatalyst in a microbial fuel cell (MFC) coupled with a homogeneous electron-Fenton (EF) process to degrade glyphosate in aqueous medium. After coupling the processes with a resistance of 100 Ω, an output voltage value of 0.64 V was obtained and maintained stable throughout the experiment. A bacterial biofilm of Serratia sp. AC-11 was formed on the carbon felt electrode, confirmed by attenuated total reflectance-Fourier transformed infrared (ATR-FTIR) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). In the anodic chamber, the GLY biodegradation rate was 100% after 48 h of experimentation, with aminomethylphosphonic acid (AMPA) remaining in the solution. In the cathodic chamber, the GLY degradation rate for the EF process was 69.5% after 48 h experimentation, with almost all of the AMPA degraded by the in situ generated hydroxyl radicals. In conclusion, the results demonstrated that Serratia sp. AC-11 not only catalyzed the biodegradation of glyphosate but also facilitated the generation of electrons for subsequent transfer to initiate the EF reaction to degrade glyphosate. This dual functionality emphasizes the unique capabilities of Serratia sp. AC-11, it as an electrogenic microorganism with application in innovative bioelectrochemical processes, and highlighting its role in sustainable strategies for environmental remediation.

Treatment of textile dyes with steel flakes via Fenton and Electro-Fenton processes: An experimental analysis

The textile production process is well recognised as one of the most water-intensive industries, with an estimated daily water consumption of several thousand cubic metres. The main objective of the study is to remove the colour and COD of three reactive dyes namely reactive blue, reactive yellow and reactive black by Fenton and Electro Fenton Process. In this research paper, new novel catalyst steel flakes have been employed as part of the Fenton and Electro-Fenton process, replacing the conventional Fenton and Electro-Fenton catalyst. Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Analysis (EDAX), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Thermo Gravimetric Analysis (TGA) was done to characterize the steel flakes. The pH, dye concentration, FeSO4 dosage and H2O2 dosage were studied. The maximum colour and Chemical Oxygen Demand (COD) removal in Fenton process was 98.47 % and 74 % respectively. In Electro Fenton Oxidation the maximum colour and COD removal was 99.65 % and 78 % respectively. The best colour and COD removal was observed by Fenton and Electro Fenton oxidation with optimum Fenton molar ratio of 50:1 and pH 3 in all three dyes. In the laboratory-scale feasibility tests on the Electro-Fenton process, the highest colour removal effectiveness was observed at catalyst dosages of 1 g/L, 132 mM H2O2, and pH 3. The novel modified heterogeneous Electro-Fenton approach presents a distinct cost-effectiveness benefit in comparison to both the conventional Electro-Fenton reaction and the Electro-Fenton reaction employing alternative iron sources.

Tuning the morphology and surface structure of MnOx@GF through Ce for high-efficiency degradation of Rhodamine B by electro-Fenton

Widespread and ineffective dye treatment in aquatic environment leads to serious pollution problems, threatening ecology and human health. Herein, manganese cerium bimetallic oxide cathode material (MnCeOx@GF) was prepared by hydrothermal method combined with calcination, and the electrochemical Fenton degradation performance of a typical dye Rhodamine B (Rh B) was investigated. The results show that the degradation of Rh B by MnCeOx@GF can reach 96.5 % within 2 h in acidic environment and continue to perform effectively after 4 repeated experiments. Combined with SEM and electrochemical test results, it can be seen that the bimetallic composite oxides formed by manganese and cerium on the surface of the support can effectively enhance the catalytic activity of the material, the addition of cerium changes the morphology of manganese oxides and promotes the generation of multiple valence composite oxides of transition metals, and improves the degradation of Rh B. Based on the free radical masking experiments, hydroxyl radical (·OH) is the main active substance in the electro-Fenton degradation process. This work not only provides a way to design and manufacture cathode materials for in situ electrosynthesis of H2O2, but also provides an important reference for improving the reusability of cathodes for sustainable dye wastewater treatment.

Selective oxidation of electron-rich pollutants in peroxymonosulfate-activated electro-Fenton system: the role of microenvironment-regulated cathode

Electro-Fenton technologies driven by peroxymonosulfate (PMS) activation have been extensively explored for abatement of organic pollutants from water. Unfortunately, a great diversity of matrix components in contaminated water scenarios inevitably and significantly compromises the efficiency of the generated radicals toward target pollutants. Thus, selective oxidation of the electro-Fenton technologies is urgently desired for cost effective and sustainable water treatment, but challenged by the traditional electron transfer pathway from cathode to PMS to mainly form SO4•− and HO• radicals. In this study, we successfully realized selective generation of 1O2, a non-radical species specific for electron-rich pollutants, by regulating the second-shell coordination environment of single-atom Fe in carbonaceous cathode. The doped electron-accepting B drives directional electron transfer from PMS to electrode and inhibiting the undesirable radical pathways. Besides, the electrochemical reduction of H+ in-situ generated from the dissociation of H-O in PMS is favourable for the formation of 1O2 as high as 163.4 μmol.L−1min−1. Fast and preferential removal of sulfonamides pollutants in different water matrices demonstrated the excellent matrix tolerance of the newly developed electro-Fenton process. A pilot electrochemical device was designed to further selective remove phenols in real-scenario application. No residual phenol was detected (<0.01 mg/L) with TOC removal around 50% (down to 23.9±0.3 mg L−1) during the continuous 24-h operation. This study is also believed to shed new light on how to achieve desirable electrochemical reactions via microenvironmental regulation in response to sustainable water decontamination and beyond.

Iron metal-organic framework nanofiber membrane for the integration of electro-Fenton and effective continuous treatment of pharmaceuticals in water

In this study, an iron metal-organic framework (Fe-MOF) was synthesized and immobilized by electrospinning technique with the objective of obtaining a membrane composed of nanofibers of this material (Fe-MOF nanofiber membrane). The characterization performed by XRD, TEM, SEM, EDS mapping and FTIR confirmed the correct synthesis of Fe-MOF as well as its correct retention in the elaborated membranes. The usefulness and effectiveness of the Fe-MOF nanofiber membrane as a catalyst for the electro-Fenton process was evaluated by performing sulfamethoxazole degradation tests. Different parameters such as the effect of intensity (25 and 100 mA), the effect of the drug initial concentration (10–50 mg/L) and the reusability of membranes were studied. Then, the degradation of a drug mixture formed by sulfamethoxazole and antipyrine was evaluated, reaching a degradation of 92.10 % and 87.43 % respectively for each drug in 4 h at 25 mA. In addition, the identification of reactive oxygen species was ascertained by scavenger assays. The study of degradation products was also carried out and their toxicity was predicted by ECOSAR program, concluding that the environmental toxicity would disappear with mineralization. Finally, given the good results obtained in batch tests, the behavior of the process was studied in a system that works continuously, achieving a stable degradation of 83.10 % in the case of treatment with a mixture of drugs. This confirmed the stability of the Fe-MOF nanofiber membrane, as well as, its catalytic activity, making it suitable for long-term treatments.

Transforming waste to purity: 3D electro-Fenton process boosted with pistachio shell-derived iron-biochar electrode for methyl violet 2B dye catalytic removal

Traditional degradation methods with typical catalysts which have limited negatively charged surfaces are not effectively degrade cationic dyes. A multi-functional iron-biochar was prepared from waste pistachio shells (Fe@PSB) that offers enhanced dye removal due to abundance of negatively charged sites for the degradation of the carcinogenic dye known as methyl violet 2B (MV 2B) in a cutting-edge three-dimensional electrochemical Fenton system (3DEF) with graphite (GP) cathode and Titanium (Ti) anode (3DEF-Ti/GP). Catalytic properties of Fe@PSB were explored for MV 2B dye degradation at broad acidic pH range. At optimum operating conditions of the current of 2.0A, pH 5.0, and Na2SO4 dose of 0.2M, nearly 98.8% of 10mg/L MV 2B dye removal was attained in 60min of electrolysis time. Commercial particle electrodes did not perform as well for the MV 2B dye degradation. The catalytic mechanism of 3DEF-Ti/GP system was investigated by quenching experiments which revealed that the hydroxyl radical (•OH) was responsible for the oxidation of dye molecules. Fe@PSB significantly performed up to four successful cycles. Liquid chromatography-mass spectrometry analysis revealed that de-methylation was the primary degradation pathway. This unique approach not only valorizes agricultural waste but also paving the way for greener environmental solutions.

Effective degradation of ciprofloxacin from aqueous solutions using heterogeneous electro-Fenton coupled with Fe@Fe2O3 core-shell nanoparticle

In the current research, a Ti/RuO2 anode and Fe@Fe2O3 catalyst were synthesized for electro-Fenton (EF) removal of ciprofloxacin (CIP). The results of the ANOVA from response surface methodology (RSM) indicated a significant relationship between experimental and predicted values. 100% CIP and 45% total organic carbon (TOC) removal were predicted at pH of 8.83, time of 14.80min, current density of 19.19mA/cm2, pollutant concentration of 15.13mg/L, and catalyst dosage of 199.03mg/L. Among the operational parameters, current density (F value = 191.90) and catalyst dosage (F value= 5.79) had the greatest and least effect on the CIP removal rate, respectively. The stability tests revealed excellent reusability of electrodes for long-term decomposition of CIP. The BOD5/TOC > 0.6 in the treated solution confirmed acceptable performance of the heterogeneous EF process in CIP degradation. A 25% growth inhibition rate of plant stems in the treated solution demonstrated the low toxicity and biodegradability of the effluent. The efficiency of the heterogeneous EF process for CIP removal in water matrices ranged from 43.65% to 100%. By evaluating the parameters, mineralization, production of different radicals, and energy consumption, the heterogeneous EF process can be considered for the effective decomposition of CIP from aqueous environments.

Effective removal of fluoride ions from contaminated water using electrochemical techniques: A critical review on recent developments and environmental perspective

Worldwide, water pollution poses significant threats to human health, with fluoride contamination emerging as a critical hazard. High fluoride concentrations in water cause severe health impacts, including dental and skeletal fluorosis, neurological damage, and harm to the parathyroid gland, cardiovascular, and reproductive systems. Electrochemical technique is one of the most widely used treatment technologies that has been extensively studied and provides a very effective, low-cost method of removing fluoride from contaminated water. The review reports the comprehensive electrochemical strategies for fluoride ions removal. The sources, toxicity, and impacts of fluoride pollution on health are discussed in this review. A comprehensive analysis of current electrochemical methods, including electrolysis, electrocoagulation, and the electro-fenton process, was provided in the context to facilitate the efficient removal of fluoride ions from wastewater. These methods exhibit high removal efficiencies, reaching up to 95 %, and offer scalability and operational flexibility, making them suitable for both centralized and decentralized water treatment systems. Furthermore, the recent advancements in the development of electrochemical technique for fluoride removal are critically reviewed. This study has prospected the recent developments, recommendations and future outlooks on electrochemical technique for fluoride removal.

Selective phthalate removal by molecularly imprinted biomass carbon modified electro-Fenton cathode

A novel molecularly imprinted biomass carbon (MIP@BC) catalyst functionalized with the virtual template of phthalates was designed as the cathode material which possesses excellent 2-electron oxygen reduction ability and H2O2 production capacity, which is suitable for targeted degradation of phthalates in the electro-Fenton system. Following molecularly imprinted modification, the adsorption capacity of MIP@BC for Dimethyl phthalate (DMP) increased by 40 %, reached 9.26 mg/g. Compared with non-imprinted biomass carbon (NIP@BC), the MIP@BC-mediated electro-Fenton process enhanced the degradation rate of DMP by 72 %. Additionally, the degradation rate of DMP rises by 51 % and 104 % respectively on the basis of river water and domestic sewage. The reactive oxygen species that induced DMP degradation were OH and O2− and targeted adsorption and catalysis exert a synergistic effect. This study provides a new insight into targeted degradation for high-toxicity of emerging contaminants from complex aqueous environment.

Synergistic enhancement of electro-Fenton redox processes by iron-molybdenum dual sites for synchronous removal of Cr (VI) and emerging organic pollutants

Synergy removal of heavy metals and emerging organic pollutants (EOPs) poses a formidable challenge in heterogeneous electro-Fenton processes. Here, we present a three-dimensional iron-doped molybdenum disulfide hierarchical microsphere/graphite felt (Fe-MoS2 HS/GF) system. This system exhibits exceptional electrocatalytic redox activity, achieving a 9.75-fold and 18.96-fold increase in Cr (VI) (2.38 × 10-2 min−1) and BPA (8.29 × 10-2 min−1) removal rates compared to the MoS2 HS/GF system, respectively. And it also exhibited a significantly enhanced mineralization efficiency (59.28 %) for BPA, surpassing that of the MoS2/GF system (5.75 %) by a factor of 10.31. Mechanistic insights indicate that the Fe-Mo dual catalytic sites effectively lower reaction barriers of H2O2 dissociation, generating significant amounts of ·OHsurface and 1O2 species for BPA degradation. Moreover, an electric field-driven the variable valence state of the Fe-Mo dual sites facilitates Fe (II) regeneration and Cr (VI) reduction. Notably, this system shows broad applicability for synchronous removal of Cr (VI) and diverse EOPs, exhibiting robust stability under unsteady-state continuous-flow operation (2 L reactor) with reduced biotoxicity in actual wastewater. This study highlights the synergistic benefits of the dual catalytic sites in the heterogeneous electro-Fenton processes for treating multicomponent wastewater.

A novel catalyst based on zero-valent iron nanoparticles for assisting electro-fenton process applied to a toxic wastewater

A catalyst based on zero-valent iron nanoparticles (nZVI) supported by zeolite Y (zeolite Y-nZVI) was synthesized to improve the performance of the heterogeneous electro-Fenton-like process for treating a toxic pesticide wastewater with pH of 6. Central Composite Design (CCD) under Response Surface Methodology (RSM) was applied to design the experiments and find the optimal parameters including time, current intensity, hydrogen peroxide volume (or concentration) and the synthesized catalyst dosage. The results showed that the chemical oxygen demand (COD) removal under the optimal conditions (time of 125 min, current intensity of 272 mA, hydrogen peroxide volume (or concentration) of 0.19 ml (8.102 × 10−3 M), and zeolite Y-nZVI catalyst dosage of 1.78 g) was at 83.69 % for treating a wastewater with pH of 6 although this increased to 91.26 % at pH of 3 under the Fenton reactions. In fact, the synthesized catalyst could properly treat wastewater in a pH close to neutral one. Since electro-Fenton is as efficient technique for treating the hazardous pollutants such as pesticide, it can successfully be used by their manufacturing factories. Since it properly works in the acidic pHs, it is not as applied technique for most of industries. Therefore, catalytic electro-Fenton process can be performed in (or near) a neutral pH. Since electro-Fenton is basically associated with iron, a catalyst based on it (such as Fe°) was chosen and supported on an abundant and suitable material such as zeolite. The synthesized catalyst was initially synthesized and characterized, and then successfully applied in the electro-Fenton process to treat a real pesticide containing wastewater obtained from industry.

Pollutants Analysis and Life Cycle Assessment of a Photovoltaic Powered Textile Electro-Fenton Wastewater Treatment System.

Textile wastewater poses a substantial environmental challenge due to the persistence of organic dyes. This study introduces a novel approach using photovoltaic (PV) powered electro-Fenton (EF) technology for effective treatment of textile wastewater. Acid orange 7 (AO7), methylene blue (MB), and malachite green (MG) were selected as representative organic dyes to validate the method under varying experimental conditions. Analysis of variance (ANOVA) highlighted the significant influence of pollutant type, pH levels, and current density on the degradation efficiency of the system, with optimal conditions observed at pH = 3 and high current density. To underscore the environmental benefits, a comprehensive life cycle assessment (LCA) was conducted. The PV-powered EF system, when implemented in a textile mill, exhibited an energy payback time (EPBT) of 9.53 years, a greenhouse gas payback time (GPBT) of 4.45 years, and a life cycle cost (LCC) of 1.9 × 105 RMB. Comparative analysis with conventional Fenton and EF processes revealed substantial energy savings, with carbon emissions reduced by 95% and 78%, and energy consumption reduced by 87% and 52%, respectively.

Degradation of phenol by metal-free electro-fenton using a carbonyl-modified activated carbon cathode: Promoting simultaneous H2O2 generation and activation

The low yield of hydrogen peroxide, narrow pH application range, and secondary pollution due to iron sludge precipitation are the major drawbacks of the electro-Fenton (EF) process. Metal-free electro-Fenton technology based on carbonaceous materials is a promising green pollutant degradation technology. Activated carbon cathodes enriched with carbonyl functional groups were prepared using a two-step annealing method for the degradation of phenol pollutants. The •OH in the activation process of H2O2 were identified using the EPR test technique. The action mechanism of carbonyl groups on H2O2 activation was investigated in conjunction with density functional theory (DFT) calculations. The EPR tests demonstrated that the modified activated carbon could promote the in-situ activation of H2O2 to •OH. And the results of material analysis and DFT showed that C=O could facilitate the activation of hydrogen peroxide through the electron transfer mechanism as an electron-donating group. Electrochemical tests showed that both the oxygen reduction activity and 2e−ORR selectivity of the modified activated carbons were significantly improved. Compared with the original activated carbon cathode and EF, the degradation efficiency of phenol in the ACNH-1000/GF cathode was increased by 58.10% and 45.61%, respectively. Compared with EF, ACNH-1000/GF metal-free electro-Fenton effectively expands the pH application range, and is proven to be less affected by solution initial pH, while avoiding secondary pollution. The metal-free electro-Fenton system can save more than a quarter of the cost of EF system. This study has a deep understanding of the reaction mechanism of the carbonyl modified activated carbon, and provides valuable insights for the design of metal-free catalysts, so as to promote its application in the degradation of organic pollutants.

Endogenously doped mixed-oxide CoO/Co2O3 in ZIF-derived carbon deposited on graphite felt for electrochemical oxidation of pharmaceutics

Some of the important goals in the development of the electro-Fenton (EF) process are to increase the performance of the electrodes while reducing their size as an alternative for expensive electrodes, expanding the active pH range, and also generating reactive oxygen species (ROSs) directly without using other homo/heterogeneous catalysts. This work modified graphite felt (GF) using a rapid and in-situ synthesis with Co/Zn doped mixed-metal ZIF. After calcination, various physicochemical analyses, including XRD, SEM, and XPS, confirmed that a carbonic material doped with mixed-oxide CoO/Co2O3 is embedded on the surface of GF fibers. LSV analysis showed that the modification significantly improved the electrode activity for O2 reduction. The modified CoZnCal-GF electrode showed good performance and higher kinetics in the EF process. It removed 87% of rifampin (RIF) in a short period of 30 min without any homo/heterogeneous catalysts. The selected conditions for this process were 1.0 V, 40 mg/L, and 5.6 for applied voltage, initial RIF concentration, and pH, respectively. The non-radical species 1O2 showed the most important role in removing RIF. LC-MS analysis was performed, and while confirming the complete removal of RIF, it was used to investigate the degradation pathway and identify the produced intermediates.

Removal of pollutants from pharmaceutical wastewater through electrofenton membrane bioreactor (EFMBR)

The treatment of effluent with diversified membrane technology related processes is not satisfying due to its own disadvantages and as a result the standard limits prescribed could not be met. This research work mainly focuses on the elimination of impediments associated with membrane bioreactors (MBRs). The irreversible fouling was found to greatly reduce by the addition of electrochemical pre-treatment processes with MBR. Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS) are the majorly considered water parameters and they are evaluated in the case of integrated electro-fenton membrane bioreactor (EFMBR), which is a hybrid technology comprising of electro-fenton pretreatment process with ozonation and MBR technology. This is proved to be highly effective with an excellent reduction percentage of 92 % COD and 50 % TDS respectively. Gas chromatography (GC) analysis of the pharmaceutical effluent upon treatment in EFMBR justified the quantitative reduction of pharmaceutical compounds. The results obtained on experimentation of EFMBR clearly indicated that there is a little internal and external fouling which is significantly proved through Hermia modelling and Scanning Electron Microscopy (SEM) analysis. The most eminent result obtained in this study were the efficacy of EFMBR to operate without the issue of filamentous bulking and it supported that electro-fenton could have played the major role for the achievement of eradicating fouling in EFMBR. The results obtained from this process gives an insight to researchers to overcome the irreversible fouling in industrial and municipal water treatment. The outcome of this study shows the insightful way employing this technology in water treatment industries could highly reduce the environmental problems.