One-step construction of hierarchical porous channels on electrospun MOF/polymer/graphene oxide composite nanofibers for effective arsenate removal from water

Excessive toxic arsenic in surface water and groundwater is a prevalent worldwide problem. A novel hierarchical porous fibrous membrane (PG/MOF), incorporating Zr-based metal organic framework (MOF-808) and graphene oxide (GO), was fabricated for arsenate removal. The well-developed nanoporous fibrous skeleton allows the exposure of adsorption sites of MOF-808 for effective arsenate removal and avoids leakage. Systematic studies on adsorption isotherms, kinetics, and filtration processes determined the practical applicability of the PG/MOF. The maximum adsorption capacity obtained from the Langmuir model was over 180 mg/g. Mechanistic analysis via SEM, FTIR, and XPS revealed that coordination and n -n interaction is responsible for the superior adsorption performance. Adsorption energy and Bader charge analysis based on DFT calculations indicated that arsenate anions are spontaneously adsorbed near the benzene ring of MOF-808 on PG/MOF. This study identified a promising method for fabricating hierarchical porous MOF-based nanofibers and provides insight into the mechanisms of arsenate adsorption.