Preparation of Ce-Ag bimetallic modified biochar composite for the efficient removal of sulfathiazole and its mechanism

Modified biochar (Ce-Ag-BC) was successfully prepared by using Camellia oleifera shell and doping with cerium (Ce) and silver (Ag). Through the results of BET, SEM, XRD, FTIR, and XPS, Ce and Ag were successfully embedded on biochar and participated in the sulfathiazole (STZ) adsorption. After being modified, high adsorption capacity of STZ on Ce-Ag-BC was observed. The maximum adsorption amount of STZ on Ce-Ag-BC was 261.84 mg/g, which was increased by more than six times compared to raw biochar (BC, 42.41 mg/g). The adsorption kinetics and isotherm on Ce-Ag-BC could be better fitted to pseudo-second-order kinetic and Langmuir isotherm model, respectively, indicating that the adsorption is mainly controlled by chemisorption and can be described as a monolayer process. The STZ adsorption process on Ce-Ag-BC is a spontaneously endothermic reaction. Besides, the adsorption mechanism on Ce-Ag-BC mainly involves pore filling, π-π interaction, hydrogen bonding, and electrostatic attraction. • Modified biochar was prepared from Camellia oleifera shell for STZ adsorption. • CeO 2 and Ag were the main form that were successfully embedded on biochar. • Six-time improvement of STZ adsorption was observed after the modification. • PSO kinetic and Langmuir isotherm can fit well to STZ adsorption on Ce-Ag-BC.