Carbonized bacterial cellulose/FeMn composite as efficient catalyst toward contaminant degradation: The crucial role of hydrogen reduction

The structure especially the active site manipulation of Fenton-like catalysts was essential for the efficient removal of organic contaminants in the aquatic environment. In this study, the carbonized bacterial cellulose/FeMn oxide composite (CBC@FeMnOx) were synthetized and modified by hydrogen (H2) reduction to obtain the carbonized bacterial cellulose/FeMn composite (CBC@FeMn), with emphasis on the processes and mechanisms for atrazine (ATZ) attenuation. The results showed that H2 reduction did not change the microscopic morphology of the composites but destroy the Fe–O and Mn–O structures. Compared with the CBC@FeMnOx composite, the H2 reduction could promote the removal efficiency from 62% to 100% for CBC@FeMn, as well as the enhancement of degradation rate from 0.021 min−1 to 0.085 min−1. The quenching experiments and electron paramagnetic resonance (EPR) displayed that the hydroxyl radicals (•OH) was the major contributor for ATZ degradation. The investigation for Fe and Mn species indicated that H2 reduction could increase the content of Fe(II) and Mn(III) in the catalyst, thus improving the generation of •OH and accelerating the cycle process between Fe(III)/Fe(II). Owing to the excellent reusability and stability, it was indicated that the H2 reduction can be considered as an efficient way to regulate the chemical valence of the catalyst, thus enhancing the removal efficiency of aquatic contaminants. [Display omitted] •Influence of H2 reduction on ATZ degradation by CBC@FeMnOx composite was studied.•The degradation rate of ATZ by CBC@FeMn was 4 times higher than those by CBC@FeMnOx.••OH was main reactive oxygen species responsible for ATZ degradation.•Enhanced Fe(II) contents and Mn(III)-induced Fe(III)/Fe(II) cycling contributed to enhanced degradation.•CBC@FeMnOx combined with H2 reduction can be used for enhanced contaminant removal from natural waters.