Synthesis of a novel core-shell-structure activated carbon material and its application in sulfamethoxazole adsorption

The increasing release of pharmaceutical and personal care products (PPCPs) into water poses serious threats to human beings. In this study, a novel core-shell activated carbon (CSAC) material with a high-mechanical strength porous ceramic shell was synthesized and tested by adsorbing sulfamethoxazole (SMX) from aqueous solutions. An activated carbon core (AC core) was synthesized from a mixture of powder AC (92%) and cassava waste splinters binder (8%). Moreover, a shell with a high thickness of 0.13 cm and compressive strength (2.92 MPa) was generated from the mixture of coal fly ash and clay at ratio of 60:40. It demonstrated high protection of the AC core. The adsorption efficiency of SMX by CSAC attained 99.0% and 97.9% at initial concentrations of 5 and 10 mg L-1, respectively. Furthermore, 77.0, 68.6 and 60.4% of SMX were adsorbed at higher concentrations of 30, 50, and 100 mg L-1, respectively. The kinetics study demonstrated that the adsorption of SMX followed pseudo-second-order kinetics. Moreover, the sorption isotherm was better fitted to Freundlich isotherms. Finally, SMX adsorption on CSAC simultaneously depended on the pore texture of CSAC and the hydrophobic properties of SMX, as well as the pi-pi bonds and electrostatic interactions between them.