As(III) oxidation and kinetic analysis by Herminiimonas arsenicoxydans-loaded electrospinning activated carbon fiber biofilms

In this study, an integrated and assembled recyclable biofilm material was prepared by loading Herminiimonas arsenicoxydans (H. arsenicoxydans) onto electrospun biomass-activated carbon nanofibers (denoted as H. arsenicoxydans-BACFs films). The H. arsenicoxydans-BACFs biofilms showed an approximately 50% increase in As(III) removal rate for 50 mg/L during a 48-h incubation. Furthermore, the biofilms demonstrated satisfactory biocompatibility, ideal catalytic As(III) oxidation and excellent recyclability in cyclic reactions (at least 5 runs). The improved catalytic efficiency is mainly due to a large amount of biomass accumulation and biofilms formation on the surface of the BACF films. More important, the BACF films as an electron transport medium from an oxidized state to a reduced state promote the electron transfer of As(III) oxidation of H. arsenicoxydans. The dual factors can synergistically promote As(III) oxidation efficiency. The oxidation process of As(III) in the H. arsenicoxydans-BACFs composite biofilm reactor was more in line with the first-order kinetic equation, and the oxidation rate of As(III) by H. arsenicoxydans-BACF0.4 was the fastest. The H. arsenicoxydans-BACF films outperformed conventional catalytic materials and could represent biomaterials for the remediation of As(III)-contaminated wastewater.