Oxalic acid modification enables high efficiency and proton conductive of Fe-base amorphous toward acid orange II in wastewater removal

Abstract

A method involving the application of an elevated proton conductive shell onto Fe-base amorphous alloys (Feam) through the mechanical ball-milling process with oxalic acid dihydrate (OA-BFeam) is presented. The investigation highlights that the resulting Fe2C2O4·shell remarkably enhances the removal rate of acid orange II (AO II) by Feam, exhibiting an approximately 2.17-fold increase. This enhancement is attributed to the superior proton conductivity of the Fe2C2O4 shell in comparison to the iron oxide shell. Consequently, protons can effectively traverse the Fe2C2O4 shell and permeate into the iron core, where they serve as reducing agents to generate H. Simultaneously, the formation of surface-adsorbed Fe2+ occurs rapidly, contributing to a highly efficient AO II removal process across a broad pH range. Additionally, it is noteworthy that OA-BFeam exhibits equivalent efficacy in the removal of both direct and reactive dyes. Overall, this work introduces an environmentally benign surface modification technique for Feam and underscores the influence of proton conductivity on the dye wastewater removal capability of Feam.