Magnesium Cobaltite Embedded in Corncob-Derived Nitrogen-Doped Carbon as a Cathode Catalyst for Power Generation in Microbial Fuel Cells

Microbial fuel cells (MFCs) have drawn attention among renewable energy devices. High capital cost, poor durability, and slow oxygen reduction reaction (ORR) kinetics are the major hindrances in the commercialization of the technology. In this work, an environmentally benign approach is followed to synthesize a composite of magnesium cobaltite (MgCo₂O₄) embedded in nitrogen-doped carbon to optimize the performance of MFCs. Detailed characterization confirms the formation of MgCo₂O₄ nanostructures in the catalyst treated at 700 °C. Electrochemical studies suggest the superior performance of the MgCo₂O₄/NC-700 catalyst with a peak reduction current of -0.068 mA and a charge transfer resistance (R_ct) of 40.5 Ω. The performance of the air cathodes is evaluated using activated sludge as inoculum in the anode chamber in single-chamber MFCs. The power output of MFC with MgCo₂O₄/NC-700 as an air cathode reaching 873.81 mW m^-2 is 59.56 and 216.05% higher than those of MFCs with Pt/C (547.65 mW m^-2) and Co/NC-700 (276.48 mW m^-2) cathodes, respectively. These findings suggest that substituting magnesium in transition metal-nitrogen-carbon composites could help realize long-term application as air cathodes for power generation and wastewater treatment in MFCs.

Treatment of dye wastewater nanofiltration concentrates containing high anion levels by a pH-sensitive nano-sized Fe(iii)@silica microgel

The pH-sensitive dual effects of Fe(iii) in heterogeneous Fenton-like degradation and enhanced coagulation with silica microgel for the treatment of refractory nanofiltration concentrates.

Synthesis of Mesoporous α-Fe2O3 Nanoparticles by Non-ionic Soft Template and Their Applications to Heavy Oil Upgrading

This paper reports the synthetic route of 3-D network shape α-Fe2O3 from aqueous solutions of iron precursor using a non-ionic polymeric soft-template, Pluronic P123. During the synthesis of α-Fe2O3, particle sizes, crystal phases and morphologies were significantly influenced by pH, concentrations of precursor and template. The unique shape of worm-like hematite was obtained only when a starting solution was prepared by a weakly basic pH condition and a very specific composition of constituents. The synthesized nanocrystal at this condition had a narrow pore size distribution and high surface area compared to the bulk α-Fe2O3 or the one synthesized from lower pH conditions. The hydrocracking performance was tested over the synthesized iron oxide catalysts with different morphologies. The worm-like shape of iron oxide showed a superior performance, including overall yield of liquid fuel product and coke formation, over the hydrocracking of heavy petroleum oil.

A Fe3O4/FeAl2O4 composite coating via plasma electrolytic oxidation on Q235 carbon steel for Fenton-like degradation of phenol

The Fe3O4/FeAl2O4 composite coatings were successfully fabricated on Q235 carbon steel by plasma electrolytic oxidation technique and used to degrade phenol by Fenton-like system. XRD, SEM, and XPS indicated that Fe3O4 and FeAl2O4 composite coating had a hierarchical porous structure. The effects of various parameters such as pH, phenol concentration, and H2O2 dosage on catalytic activity were investigated. The results indicated that with increasing of pH and phenol content, the phenol degradation efficiency was reduced significantly. However, the degradation rate was improved with the addition of H2O2, but dropped with further increasing of H2O2. Moreover, 100 % removal efficiency with 35 mg/L phenol was obtained within 60 min at 303 K and pH 4.0 with 6.0 mmol/L H2O2 on 6-cm(2) iron oxide coating. The degradation process consisted of induction period and rapid degradation period; both of them followed pseudo-first-order reaction. Hydroxyl radicals were the mainly oxidizing species during phenol degradation by using n-butanol as hydroxyl radical scavenger. Based on Fe leaching and the reaction kinetics, a possible phenol degradation mechanism was proposed. The catalyst exhibited excellent stability.

Continuous degradation of BTEX in landfill gas by the UV-Fenton reaction

Application of the UV-Fenton reaction in waste gas treatment with enhanced gas–liquid mass transfer efficiency using a bubble column reactor.

Mesoporous silica coating on hierarchical flowerlike Fe2O3 with enhanced catalytic activity for Fenton-like reaction

The catalytic activity of hierarchical flowerlike Fe₂O₃ in the Fenton-like reaction was dramatically enhanced by the mesoporous silica coating.

Recycling rice straw derived, activated carbon supported, nanoscaled Fe3O4 as a highly efficient catalyst for Fenton oxidation of real coal gasification wastewater

Recycled rice straw was converted into an activated carbon support for nanoscaled Fe₃O₄.

Production of martite nanoparticles with high energy planetary ball milling for heterogeneous Fenton-like process

Natural martite microparticles (NMMs) were prepared with a high energy planetary ball mill to form a nanocatalyst for a Fenton-like process.

Heterogeneous Fenton-like oxidation of petrochemical wastewater using a magnetically separable catalyst (MNPs@C): process optimization, reaction kinetics and degradation mechanisms

MNPs@C magnetic composite was synthesized and applied as a heterogeneous catalyst in the Fenton oxidation for PCW treatment. The organic compounds were degraded by the ˙OH radicals released from decomposition of H₂O₂ in the presence of MNPs@C.

Hydrophilic modification of ordered mesoporous carbon supported Fe nanoparticles with enhanced adsorption and heterogeneous Fenton-like oxidation performance

Ordered mesoporous carbon with Fe nanoparticles (Fe/meso-C) underwent hydrophilic surface modification with hydrogen peroxide, which shows enhanced adsorption and heterogeneous Fenton oxidation performance for methylene blue.

Evaluation of cobalt oxide, copper oxide and their solid solutions as heterogeneous catalysts for Fenton-degradation of dye pollutants

Co_0.5Cu_0.5O nanoparticles were synthesized via the calcination of corresponding oxalates and showed outstanding catalytic performance for the Fenton-degradation of Congo red.