Regeneration of Caramel Saturated Activated Carbon jointly by Microwave and Extractive Method

Abstract

Abstract In this study, the spent activated carbon (AC) saturated with caramel was regenerated using solvent assisted with microwave radiation. The efficiency of regeneration was evaluated under parameters such as power and time of microwave radiation, and concentrations and pH of an activator. The quality of regenerated AC (RAC) was assessed by methylene blue (MB) and iodine adsorption. The optimum condition for AC regeneration was under a microwave power of 680 W and 10 min radiation, with 20% ethyl alcohol in the activator and pH of 9–10. Under this condition, the adsorption of iodine and MB on RAC was 878 and 218 mg/g, respectively. The micro structure of RAC was characterized by SEM observation. The surface area of RAC was determined under N2 sorption. The pore size distributions of virgin and RAC determined by Horvath–Kawazoe (HK) and DFT methods resulted in a mean pore diameter of 1.2 nm and a pore volume of 1 cm3/g. A regeneration efficiency of more than 85% could be achieved by microwave assisted solvent regeneration.