Oxidation of Ceftazidime by Modified Rice Husk Biochar-Activated Persulfate

Rice husk biochar (RHB-2) was prepared from agricultural waste rice husk by high-temperature pyrolysis and modified with NaOH. The char structure before and after modification was characterized by FT-IR, XRD, SEM, and XPS techniques. The effects of different parameters (initial pH of the solution, biochar dosing, persulfate concentration, reaction temperature, and inorganic anions in the solution) on the degradation of ceftazidime were investigated. There is a preliminary examination of the kinetics and reaction mechanism of the alkali-modified rice husk biochar-activated persulfate (PS) for the degradation of ceftazidime. The results indicated that removing ceftazidime by RHB-2/PS is significantly higher than single RHB-2, PS, and RHB-1/PS systems. Under the conditions of biochar dosage of 3 g/L, persulfate concentration of 10 mmol/L, reaction temperature of 60 degrees C, and no adjustment of initial solution pH, the removal of ceftazidime by RHB-2/PS system reached 95.2% in 80 min. Additionally, the degradation rate could reach 46.67% after the rice husk biochar has been recycled four times, which indicated that rice husk biochar has good reusability and stability. Ceftazidime degradation in the RHB-2/PS system was according to the first-order reaction kinetic model and the identification of radical species demonstrated that the dominant radical for ceftazidime degradation is the sulfate radical.Graphical AbstractThis study focuses on the use of agricultural waste rice husk as a raw material, using alkali modification technology and the high activation catalytic material prepared by calcination at high temperature, in synergy with the efficient removal of the target pollutant ceftazidime by persulfate. Optimum conditions: 3 g/L catalyst, 10 mmol/L persulfate concentration, 60 degrees C reaction temperature, no change in pH of the initial solution, 95.2% degradation of ceftazidime in 80 min