Three-dimensional hierarchical porous sludge-derived carbon supported on silicon carbide foams as effective and stable Fenton-like catalyst for odorous methyl mercaptan elimination

Abstract

The poor reusability of catalysts and secondary pollution are critical issues for sulfur-containing volatile organic compounds (S-VOCs) removal. In this paper, a three-dimensional (3D) hierarchical porous sludge-derived carbon supported on silicon carbide foams (SiC) has been fabricated for deep decomposition of S-VOCs under ambient conditions. The sludge-derived Fenton-like catalyst has been confirmed to be hierarchical 3D porous structure based on detailed characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), Nitrogen adsorption-desorption measurements and Raman spectroscopy. Significantly, the catalyst after KOH activation (SCFeK-SiC) shows excellent catalytic decomposition of methyl mercaptan (CH3SH) with almost complete CH3SH oxidation into sulfate using hydrogen peroxide as an oxidant under ambient conditions. This catalyst also possesses relative low iron dissolution and excellent cycling performance. The efficient catalytic ability of SCFeK-SiC can be attributed to SiC foam functioned as a stable 3D macroporous skeleton, in which the porous sludge-derived carbon immobilizes the active iron species and promotes the efficient capture of gaseous CH3SH, thus facilitating the decomposition of CH3SH by generating reactive species, specifically ·OH. The reaction mechanism was systematically investigated. Herein, the design of the porous sludge-derived carbonaceous Fenton-like catalyst paves an avenue for efficient VOCs treatment and rational sludge disposal.