Preparation of sludge-based activated carbon for adsorption of dimethyl sulfide and dimethyl disulfide during sludge aerobic composting

Abstract

Emission of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) during sludge aerobic composting has limited the use and development of this economical sludge treatment process. In this study, cheap and easily available sludge was used as raw material for the preparation of adsorbents to eliminate DMS and DMDS. A series of sludge-based activated carbons (SACs) were prepared by acid or base activation, and coconut shell mix was also assessed. The results revealed that SAC preparation by KOH activation without coconut shell mix could significantly enhance the surface area and pore volume of SAC, and showed the maximum adsorption capacity for DMS (53.45 mg g^-1) and DMDS (151.28 mg g^-1). In addition, SAC had a good adsorption effect on a mixture of DMS and DMDS. The SAC adsorbents could efficiently adsorb DMS and DMDS after four cycles of regeneration. Thermodynamic and kinetic analyses demonstrated that adsorption between the SAC and DMS/DMDS was via physical adsorption. The SAC developed in this study utilized waste in a useful way that could significantly reduce the cost of adsorbents and use them for odor elimination during sludge aerobic composting.

Keywords: Adsorption; Aerobic composting; Dimethyl disulfide; Dimethyl sulfide; Sludge-based activated carbon.