Regeneration of saturated activated carbon with thermally activated persulfate by static and dynamic methods

Abstract

Currently, the traditional post-regeneration methods for activated carbon include thermal regeneration, biological regeneration, electrochemical regeneration, and so on. In this study, the regeneration of ofloxacin-saturated activated carbon using thermally activated persulfate oxidation by both static (i.e., water bath) and dynamic (i.e., flow) methods were investigated. For static regeneration, the experimental variables were potassium persulfate (KPS) concentration, H₂O₂ concentration, the pH of the regeneration solution, regeneration temperature, and regeneration time. Our results showed the optimal conditions to be 10 mmol/L, 25 %, 7, 60 °C, and 2 h, respectively, providing a regeneration rate of 56.19 %. For dynamic regeneration, which was performed by pumping a KPS solution through a fixed bed of ofloxacin-saturated activated carbon, the experimental variables were KPS concentration, regeneration temperature, carbon-layer height, flowrate, and regeneration time, and the optimal values were found to be 100 mM, 85 °C, 5 cm, 10 mL/min, and 1.5 h, respectively, providing a regeneration rate of 52.5 %. Thus, our study presents low-cost, environmentally benign methods for the regeneration of spent activated carbon used in water-treatment facilities.