Schwertmannite modified with ethanol: A simple and feasible method for improving As(III) adsorption capacity

As a poorly crystalline Fe(III)–oxyhydroxy sulfate mineral, schwertmannite (Sch) was effectively utilized for the arsenic contamination purification. In this study, in order to improve the adsorption capacity and realize batch production, ethanol modified Sch (EtOH–Sch) has been successfully chemo–synthesized through H2O2 rapid oxidation. As the volume ratio of EtOH to water was 20%, the As(III) removal efficiency by EtOH–Sch was the highest. Through the characterization, EtOH-Sch showed the clear and discrete sea urchin-like spheres with larger specific surface area and optimized structure. EtOH–Sch exhibited excellent adsorption capacity for As(III) in a wide pH range of 6–12. As(III) removal by EtOH–Sch followed the Langmuir model and pseudo-second-order kinetics, with the maximum As(III) adsorption capacity of as high as 194.93 mg/g. In addition, the enhanced mechanism for As(III) adsorption by EtOH–Sch was proposed, including increased active sites and optimized specific structure. The excellent adsorption capacity as well as relatively good reusability of EtOH-Sch indicated its promising prospects in the application of arsenic remediation.