One-pot synthesis of sulfur doped activated carbon as a superior metal-free catalyst for the adsorption and catalytic oxidation of aqueous organics

Abstract

Synthesis of S-doped activated carbon with a well-developed porous structure and enhanced catalytic activity has been extensively investigated because of its great potential applications in various fields. Here, we report a facile one-pot thermal process for the preparation of in situ S-doped activated carbon by using a potential waste material (poly(phenylene sulphide) (PPS)) as the precursor, and KOH as the activator for the adsorptive and oxidative removal of aqueous organics. Experimental results demonstrated that the as-prepared sample treated at 800 °C (S-AC-800) exhibited both strong adsorption ability and enhanced persulfate (PS) activity for the removal of phenols. The effect of adsorption on oxidation was illustrated by investigating the removal of different phenol organics in their individual solutions and mixture solution. It was suggested that a higher adsorption capacity led to a more rapid degradation process. In the process, the adsorbed organics were preferentially in situ degraded, which in turn accelerated the adsorption, and then the adsorption and oxidation synergistically promoted the efficient removal of organics. Quenching experiments demonstrated that the activation of PS mainly proceeded through both surface-bound radical and non-radical pathways. The effects of several operating parameters as well as the influences of various inorganic anions, and background organic matter in water on organic removal were investigated in detail. In addition, the stability of S-AC-800 and its deactivation reason were also studied. It is expected that this work could not only provide a promising way to utilize PPS waste, but also provide a facile, economical and effective method for the future development of more efficient sulfur-doped activated carbons for wastewater treatment.