Preparation of mCuxO@AC through impregnation microwave method for the removal of sulfamethazine from water

In this study, a low-cost microwave-assisted impregnation method is employed to simultaneously load cupric oxide (CuO) and cuprous oxide (Cu2O) onto the surface of pretreated coal-based activated carbon (PAC), resulting in the preparation of mCuxO@AC composite material. The successful loading of the bimetallic oxides with a copper mass fraction of 0.7 % is confirmed through various characterization techniques, including SEM, EDS, XRD, XPS, and BET. Compared to hydrochloric acid-pretreated activated carbon (HAC), the mCuxO@AC exhibits a reduction in its surface basic functional groups while an enhancement in the acidic functional groups, along with a 39.2 % and 76.8 % increase in specific surface and total pore volume, respectively. Using Sulfamethazine (SMZ) as the target pollutant, the mCuxO@AC's adsorption thermodynamics, kinetics, and mechanisms are systematically investigated. The results reveal that under optimal conditions (pH = 6, C0 = 20 mg/L, T = 30 degrees C), the maximum adsorption capacity of mCuxO@AC for SMZ reaches 17.6 mg/g, representing a 21.2 % improvement over PAC. Moreover, the adsorption process follows the Langmuir isotherm and pseudo-secondorder kinetics, primarily governed by pore adsorption, electrostatic interactions, and metal coordination. In addition, compared to the traditional calcination method, this study significantly reduces the equipment cost (by 90 %) and modification time (by nearly 4 h) for activated carbon modification. By optimizing the Cu2+ impregnation concentration, the leaching concentration of Cu2+ is reduced by 58.65 %. This technology is characterized by low cost, high efficiency, and environmental friendliness, demonstrating broad application prospects in water treatment, soil remediation, medicine, and food industries.