Electric-field enhanced three-dimensional flexible carbon felt as a host for Pt4+ ions extraction

Abstract

The extraction of the precious metal Pt4+ ions from aqueous solution are of great importance for both economic development and environmental protection. In this study, an electric field assisted adsorption process with high efficiency and recyclability was explored in a self-made device using three-dimensional (3D) flexible carbon felt (FCF) as the adsorbent without using conductive adhesive. Under the aid of an electric field (0.4 V), 3D pristine FCF (p-FCF) showed a considerable adsorption capacity for Pt4+ (82 mg/g). As high as 203 mg/g was obtained when o-NFCF adsorbents modified with N doping and surface oxygen-containing groups was used. Kinetic and thermodynamic studies show that the electric field would enhance the interactions between the adsorbent and Pt4+ ions, and improve the intraparticle diffusions. Mechanism study showed that the synergistic effect between N doping and oxygen-containing groups might efficiently tune the electrochemical properties of 3D FCF materials, which significantly contributed to the enhanced adsorption of Pt4+. The electroadsorption technology developed in this study provides a simple and efficient method for industrial recovery of precious metal ions.