Adsorption of carbamazepine on self-endowed magnetic biochar produced from iron-rich sludge

Abstract

The preparation of magnetic biochar usually requires additives and additional synthesis steps, which leads to a significant increase in preparation costs. In this study, self-endowed magnetic biochar derived from iron-rich sludge was prepared via one-step pyrolysis to adsorb carbamazepine in water. The results show that when the initial concentration of carbamazepine is 5 mg L⁻¹ and the dosage of self-endowed magnetic biochar is 0.9 g L⁻¹, the removal efficiency of carbamazepine by self-endowed magnetic biochar can reach 90.1%, and the adsorption performance is excellent in a wide pH range. The adsorption of carbamazepine by self-endowed magnetic biochar can be well fitted by Langmuir an adsorption isotherm and pseudo-second-order adsorption kinetic model, which indicates that the adsorption process is single molecular layer chemisorption. In addition, self-endowed magnetic biochar has good magnetic properties, and can be effectively separated and recovered by an external magnetic field after use, and the adsorption rate of carbamazepine can still reach 81.4% after repeated use for 5 times. The adsorption mechanism of carbamazepine by self-endowed magnetic biochar includes pore filling, complexation, π–π interaction and hydrogen bonding.