Sulfamethoxazole removal of adsorption by carbon – Doped boron nitride in water

Carbon doped boron nitride (BCN) was synthesized by one-step oxygen limiting method. The BCN was characterized by XRD, SEM, FTIR, XPS and Zeta. The effects of initial concentration, time, pH and temperature of BCN on the removal of Sulfamethoxazole (SMX) were also studied. The experiments showed that the removal efficiency of SMX by BCN was better at low temperature. In the first ten minutes, the adsorption effect is very fast, and the adsorption capacity can basically reach half of the total adsorption capacity. According to the adsorption kinetic model of SMX adsorbed by BCN in solution, it was found that the adsorption conforms to pseudo second-order kinetic model and belongs to chemical adsorption. By fitting the adsorption isotherm, it was found that the fitting was more consistent with Langmuir adsorption isotherm model, and the maximum adsorption capacity was 28.75 mg·g-1 at 10 °C. In addition, the thermodynamics of adsorption was also studied, which proved that the reaction could be spontaneous. Moreover, the adsorption mechanism of BCN on SMX includes hydrogen bonding, π-π interactions and electrostatic interaction. And, after six adsorption/desorption cycles, the adsorption capacity can still reach 82%.