Preparation of sulfur self-doped coal-based adsorbent and its adsorption performance for Cu2+

Abstract

Abstract The limited application of high sulfur coal (HSC) and the increasing severity of copper pollution in solution are two pressing issues. To alleviate such issues, a sulfur self-doped coal-based adsorbent (HSC@ZnCl2) was obtained by pyrolysis-activation (850 ℃, 60 min holding time) of HSC and ZnCl2 with a mass ratio of 1:0.5. Characterizations including scanning electron microscope (SEM) and X-ray diffraction (XRD) confirmed that HSC@ZnCl2 exhibited part rough and part smooth surface, and sulfur in HSC could combine with Zn2+ to form the adsorption site ZnS. Cu2+ adsorption experiments indicated that the adsorption process followed the Sips isothermal adsorption model and the pseudo-second-order kinetic model with an adsorption capacity of 12 mg/g. Zeta potential and X-ray photoelectron spectroscopy were performed to elucidate the adsorption mechanism of Cu2+ onto HSC@ZnCl2, which primarily involved complexation, electrostatic attraction and surface precipitation. Funding from this work indicate that preparation of sulfur self-doped coal-based adsorbent prepared from high sulfur coal are a promising method for its large-scale utilization.