Three-dimensional electro-Fenton Research Articles

Preparation of Fe-Loaded Needle Coke Particle Electrodes and Utilization in Three-Dimensional Electro-Fenton Oxidation of Coking Wastewater

Preparation of Fe-Loaded Needle Coke Particle Electrodes and Utilization in Three-Dimensional Electro-Fenton Oxidation of Coking Wastewater

Three-dimensional Electro-Fenton degradation for fulvic acids with Cu-Fe bimetallic aerogel-like carbon as particle electrode and catalyst: Electrode preparation, operation parameter optimization and mechanism

In this study Cu-Fe bimetallic aerogel-like carbon based on sodium alginate (SA) was prepared as catalytic particle electrode by freeze-drying and carbonization process. The characterization indicates that Cu and Fe were loaded on the surface and inside SA-based biomass carbon (SAC) in the form of a zero-valent copper-iron alloy to form a Cu-Fe/Sodium alginate Carbon (Cu-Fe/SAC) particle electrode. After using a three-dimensional Electro-Fenton (3D-EF) system with the prepared particle electrode, the optimal experimental operating parameters for removal of fulvic acid (FA) were obtained as follows: voltage 2.5 V, pH 5.4, and catalyst dosage 4 g/L. A removal efficiency from 82.9% to 74.4% for FA was achieved in a wide pH range of 3–7. Comparison experimental results indicate that the 3D-EF system with bimetallic Cu-Fe/SAC as the catalytic particle electrode (CPE) has higher FA degradation rate and mineralization efficiency than two-dimensional Electro-Fenton (2D-EF) system, even higher than the 3D-EF system with Cu/SAC or Fe/SAC. Hydroxyl radicals (·OH) trapping experiments showed that the main contribution to FA degradation and mineralization in the 3D-EF system would be the ·OH radical produced by a heterogeneous Fenton-like reaction. The comparison and trapping experiment results indicate that the possible mechanism of the 3D-EF with Cu-Fe/SAC as CPE for FA degradation may involve adsorption, anode oxidation, heterogeneous and homogeneous Fenton-like reactions.

Degradation of mefenamic acid using magnetic multi-walled carbon nanotube as a novel particle electrode in a three-dimensional electro-Fenton process

Degradation of mefenamic acid using magnetic multi-walled carbon nanotube as a novel particle electrode in a three-dimensional electro-Fenton process

Electrospun spongy zero-valent iron as excellent electro-Fenton catalyst for enhanced sulfathiazole removal by a combination of adsorption and electro-catalytic oxidation.

In this study, a highly active electro-Fenton catalyst, spongy zero-valent iron (ZVI), has been developed at first via in-situ synthesis of ZVI nanoparticles (NPs) on an electrospun three-dimensional (3D) nanofiber network. The spongy ZVI effectively overcame the defects of easy aggregation of ZVI NPs and ferric sludge accumulation during the electro-catalytic process. Then, a three-dimensional electro-Fenton (3D-EF) system using the as-fabricated spongy ZVI as particle catalytic electrodes was designed, which presented a significant synergistic effect of adsorption and electro-catalytic oxidation on the enhanced removal of a widely used antibiotic, sulfathiazole (STZ) from water. Adsorption experiments demonstrated that the spongy ZVI had a relative high adsorption affinity towards STZ with about 50% of the total removal within 240 min, and the adsorption equilibrium was reached in 570 min. Hydroxyl radical (OH) was produced in the 3D-EF system with spongy ZVI catalyst, and almost 100% STZ was removed within 5 min. Reactive oxygen species analysis verified that OH was mainly responsible for the STZ degradation. Based on intermediates identified by a liquid chromatography-tandem mass spectrometry (LC-MS/MS), three pathways for the electro-Fenton oxidative degradation of STZ were proposed.

Application of three-dimensional electrofenton process using MWCNTs-Fe3O4 nanocomposite for removal of diclofenac

Abstract The electrochemical removal of diclofenac (DCF) in aqueous solution was investigated by three-dimensional electrofenton (3DEF) process using Ti/TiO2-RuO2 anode electrode in the presence of composites of multi-walled carbon nanotubes (MWCNTs) and magnetite (Fe3O4) nanoparticle. The response surface methodology (RSM) coupled with central composite design (CCD) was used to evaluate the effects of different variables on the removal of DCF. Based on the experimental results, an empirical relationship between response and independent variables was obtained and expressed by a quadratic polynomial equation. Maximum DCF removal was 98.52% in optimum conditions at initial pH of 5.56, DCF concentration of 6.71 mg/L, the current density of 19.74 mA/cm2, MWCNTs-Fe3O4 concentration of 58.33 mg/L, and electrolysis time of 82.24 min. The chemical oxygen demand (COD) removal efficiency and H2O2 production in the 3DEF system were much higher than other electrocatalytic processes. This is related to the presence of MWCNTs-Fe3O4 as a particle electrode that can activate the molecular oxygen for higher production of hydrogen peroxide (H2O2) and hydroxyl radical (•OH). The MWCNTs-Fe3O4 nanocomposite indicated a high degree of stability and reusability. Additionally, 1-(2,6-dichlorophenyl) indolin-2-one, 2,6- dicholoaniline, 2,4- dichlorophenol, and 1,2- benzene dicarboxylic acid were identified as main oxidation products after 60 min reaction. Based on the reaction intermediate identified, a possible pathway for the electrochemical oxidation of DCF by the 3DEF process was proposed. Eventually, the 3DEF system with MWCNTs-Fe3O4 particle electrodes can be considered as a viable alternative for DCF removal from aqueous solution.

A novel three-dimensional electro-Fenton system and its application for degradation of anti-inflammatory pharmaceuticals: Modeling and degradation pathways

Abstract A novel three-dimensional electro-Fenton (3D EF) system with iron- coated nickel foam particles (NFP-Fe) and bare nickel foam as catalytic particle electrodes (CPEs) was employed in this study. Its application in degrading ibuprofen (IBP) and naproxen (NPX), two widely-used nonsteroidal anti-inflammatory drugs (NSAIDs), exhibited high catalytic efficiency in a near-neutral pH. Response surface methodology (RSM) was applied to assess the individual and interaction effects of several operating variables (pH, reaction time, concentrations of target compounds and current density) on the IBP and NPX removal efficiencies and energy consumption (EC). Based on the analysis of variance (ANOVA), the coefficient of determination (R2) was calculated and found to be above 99.4% for all the responses. The maximum IBP and NPX removal efficiencies were found to be 98.14% and 93.5% under the optimum conditions, respectively. After 60 min of treatment at a current density of 15 mA/cm2 and pH 3–6, EC of 3D EF (168.6 and 112.19 kWh/kgCOD) was much lower than (two-dimensional) 2D EF (360.18–909.20 kWh/kgCOD). The kinetics analysis showed that the abatement of COD in both systems followed apparent pseudo first-order reaction. Furthermore, based on the major reaction intermediates were identified by a novel DLLME/GC/MS and the results of previous studies, the possible degradation pathway was proposed. The aforementioned results highlighted 3D EF as a promising alternative method for the remediation of aqueous solutions contaminated with NSAIDs.

Microbial fuel cells coupling with the three-dimensional electro-Fenton technique enhances the degradation of methyl orange in the wastewater.

The emission of the source effluent of azo dyes has resulted in a serial of environmental problems including of the direct damage of the natural esthetics, the inhibition of the oxygen exchange, the shortage of the photosynthesis, and the reduction of the aquatic flora and fauna. A bioelectrochemical platform (3D-EF-MFCs) combining two-chamber microbial fuel cells and three dimensional electro-Fenton technique were delicately designed and assembled to explore the decolorization, bio-genericity performance of the methyl orange, and the possible biotic-abiotic degradation mechanisms. The 3D-EF-MFCs processes showed higher decolorization efficiencies, COD removals, and better bioelectricity performance than the pure electro-Fenton-microbial fuel cell (EF-MFC) systems. The two-chamber experiments filling with the granular activated carbons were better than the single-chamber packing system on the whole. The moderate increase of Fe2+ ions dosing in the cathode chamber accelerated the formation of •OH, which further enhanced the degradation of the methyl orange (MO). The cathode-decolorization and COD removals were decreased with the increase of MO concentration. However, the degradation performance of MO was indirectly improved in the anode compartment at the same conditions. The bed electrodes played a mediator role in the anode and cathode chambers, certainly elevated the voltage output and the power density, and lowered the internal impedance of EF-MFC process.

Degradation of folic acid wastewater by electro-Fenton with three-dimensional electrode and its kinetic study.

The three-dimensional electro-Fenton method was used in the folic acid wastewater pretreatment process. In this study, we researched the degradation of folic acid and the effects of different parameters such as the air sparging rate, current density, pH and reaction time on chemical oxygen demand (COD) removal in folic acid wastewater. A four-level and four-factor orthogonal test was designed and optimal reaction conditions to pretreat folic acid wastewater by three-dimensional electrode were determined: air sparge rate 0.75 l min−1, current density 10.26 mA cm−2, pH 5 and reaction time 90 min. Under these conditions, the removal of COD reached 94.87%. LC-MS results showed that the electro-Fenton method led to an initial folic acid decomposition into p-aminobenzoyl-glutamic acid (PGA) and xanthopterin (XA); then part of the XA was oxidized to pterine-6-carboxylic acid (PCA) and the remaining part of XA was converted to pterin and carbon dioxide. The kinetics analysis of the folic acid degradation process during pretreatment was carried out by using simulated folic acid wastewater, and it could be proved that the degradation of folic acid by using the three-dimensional electro-Fenton method was a second-order reaction process. This study provided a reference for industrial folic acid treatment.

Three-dimensional heterogeneous electro-Fenton oxidation of biologically pretreated coal gasification wastewater using sludge derived carbon as catalytic particle electrodes and catalyst

A novel catalytic particle electrode (CPE) was prepared and applied in three-dimensional electro-Fenton (3D EF) for the treatment of biologically pretreated coal gasification wastewater and the performance was compared to that of pure Fe3O4 magnetic nanoparticles (MNPs). The sewage sludge derived activated carbon-supported iron oxide (SAC-Fe) was synthesized from sewage sludge and iron sludge via a facile method and served as both CPEs and catalyst in 3D EF. The results revealed that SAC-Fe had higher adsorption capacity and degradation efficiency than Fe3O4 MNPs. 3D EF with the addition of this novel CPE exhibited excellent treatment performance in pollutants and toxicity removal and biodegradability of the treated wastewater was improved remarkably. Based on the measurements of H2O2 and HO*, it was deduced that the enhancement of catalytic activity was responsible for generating more H2O2 and HO*. Meanwhile, the stability and reusability of the CPEs were also evaluated. SAC-Fe was promising to be potentially used as CPEs in 3D EF to remove organic pollutants in wastewater.

Novel bentonite particle electrodes based on Fenton catalyst and its application in Orange II removal

AbstractNovel particle electrodes, Fe species-modified bentonite (Fe-Bent) were synthesized using a rapid and completely green method employing aqueous green tea extracts as both the reducing and capping agents. The prepared Fe-Bent was characterized using UV–vis spectra, X-ray diffraction, Brunauer–Emmett–Teller, and Fourier transform infrared spectra techniques, and then utilized as heterogeneous Fenton catalyst to constitute a three-dimensional electro-Fenton (3D/E-Fenton) system for decolorization of orange II in aqueous solution. Batch experiment results show that 98.89 and 71.57% of decolorization and chemical oxygen demand (COD) removal were obtained at 0.5 g of Fe-Bent dosage, 0.05 mol L−1 Na2SO4, and initial solution pH of 6.4, respectively. The evolution of instantaneous current efficiency shows that the 3D/E-Fenton system exhibited higher efficiency for orange II degradation than that of 2D system. In addition, the possible mechanism of the 3D/E-Fenton system in the degradation of orange II was...

A novel integration of three-dimensional electro-Fenton and biological activated carbon and its application in the advanced treatment of biologically pretreated Lurgi coal gasification wastewater

A novel integrated process with three-dimensional electro-Fenton (3D EF) and biological activated carbon (BAC) was employed in advanced treatment of biologically pretreated Lurgi coal gasification wastewater. SAC-Fe (sludge deserved activated carbon from sewage and iron sludge) and SAC (sludge deserved activated carbon) were used in 3D EF as catalytic particle electrodes (CPEs) and in BAC as carriers respectively. Results indicated that 3D EF with SAC-Fe as CPEs represented excellent pollutants and COLOR removals as well as biodegradability improvement. The efficiency enhancement attributed to generating more H2O2 and OH. The integrated process exhibited efficient performance of COD, BOD5, total phenols, TOC, TN and COLOR removals at a much shorter retention time, with the corresponding concentrations in effluent of 31.18, 6.69, 4.29, 17.82, 13.88mg/L and <20 times, allowing discharge criteria to be met. The integrated system was efficient, cost-effective and ecological sustainable and could be a promising technology for engineering applications.

Design of a neutral three-dimensional electro-Fenton system with various bentonite-based Fe particle electrodes: A comparative study

Three-dimensional electrochemical reactor coupling electro-Fenton degradation of phenol with three kinds of bentonite-based various iron species (Fe-Bent): Fe3O4-Bent, Fe2O3-Bent and Fe0-Bent, as particle electrodes at original pH (6·24) was investigated. At the optimal reaction conditions, a maximum of 92·48% phenol removal and 67·48% chemical oxygen demand removal were achieved in the presence of Fe0-Bent. By evaluating Fe leaching behaviours from the particle electrodes during the degradation of phenol, it was found that both homogeneous and heterogeneous electro-Fenton reactions were all involved in the phenol degradation. Moreover, the evolution of ·OH was evaluated and its relationship with Fe leaching and phenol removal was also discussed. The results show that Fe0-Bent can act as the most efficient catalyst in this system at natural conditions, and the feasibility of the proposed combined system of electro-Fenton and three-dimensional electrochemical reactor in the removal of pollutant from wastewater.