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Pyrogenic biomass carbon has been deemed a promising alternative to Pt/C for the oxygen reduction reaction (ORR) owing to its low cost, excellent activity, and eco-friendly properties. Herein, a porous carbon tube material derived from kapok fibres was prepared by combining activation with pyrolysis. Electrochemical measurements demonstrated that the kapok fibre-derived material prepared at 900°C had excellent ORR performance with a half-wave potential −0.14 V (vs. Ag/AgCl) close to that of commercial Pt/C (−0.13 V vs. Ag/AgCl) in 0.1 mol L−1 KOH. The prepared material also displayed remarkable methanol tolerance and durability. Furthermore, the maximum power density output of the microbial fuel cell using the prepared material was (801±40) mW m−2, comparable to that of the Pt/C cathode ((778±31) mW m−2). The present work provides a facile way of using economical and renewable biomass to develop a porous structure and high-activity cathode ORR catalyst for fuel cell applications. [ABSTRACT FROM AUTHOR]

BACKGROUD Organic contaminants in secondary reverse osmosis (SRO) concentrate pose a severe threat to the ecosystem, due to their potential toxicity. In this study, potential of coagulation/granular activated carbon (GAC) adsorption combined with UV/H2O2 and ozonation for removing organic matter from industrial secondary RO concentrate was systematically investigated. RESULTS: Coagulation with 2.0 mmol L−1 FeCl3 yielded 40% removal of dissolved organic carbon (DOC), while adsorption with 5 g L−1 GAC could boost the removal efficiency up to 78.2%. Fractionation results showed that both coagulation and GAC adsorption favored hydrophobic organics. UV/H2O2 oxidation was capable of removing 87.4% of DOC, which outperformed ozonation (58.2%). UV/H2O2 and ozonation showed similar behavior in dissolved organic matter (DOM) degradation: a portion of hydrophobic organics were first transformed into hydrophilic fractions prior to final mineralization. Conclusion: Coupling of GAC as post‐treatment with a UV/H2O2 process yielded 97.9% removal of DOC and the corresponding electrical energy per order (EE/O) was decreased from 66.7 to 35.8 kWh m−3. Consequently, a simple UV/H2O2 and GAC hybrid process was proposed to be a suitable method for removing DOM from SRO concentrate. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]