Adsorption of Cu2+ and Cd2+ from aqueous solution by novel electrospun poly(vinyl alcohol)/graphene oxide nanofibers

Abstract

Novel poly(vinyl alcohol)/graphene oxide (PVA/GO) nanofibers were fabricated by electrospinning and applied to remove Cu²⁺ and Cd²⁺ from aqueous solution. The adsorption performances of the PVA/GO nanofibers were investigated by removing Cu²⁺ and Cd²⁺. The results showed that the adsorption of Cu²⁺ and Cd²⁺ onto PVA/GO nanofibers increased as the pH was increasing, but only slightly reduced with the increasing of ionic strength. The adsorption could reach equilibrium within 25 min and the experimental kinetic data followed the pseudo-second-order kinetic model. The equilibrium adsorption data can be well fitted with the Langmuir model. The thermodynamic parameters calculated from adsorption isotherms at four different temperatures indicated that the adsorption processes were endothermic and spontaneous. The PVA/GO nanofibers have good regeneration ability and can be recycled 8 times with a small amount of loss in adsorption efficiency. FTIR and XPS results indicated that the carboxyl and the carbonyl groups of GO on the surface of the nanofibers mainly participated in the adsorption of Cu²⁺ and Cd²⁺.