Comparative study of atrazine degradation by magnetic clay activated persulfate and H(2)O(2)

To effectively remove the endocrine disrupting chemicals (EDCs) in water, Fe(3)O(4) was loaded on the surface of modified sepiolite clay by the method of co-precipitation to catalyze potassium persulfate (K(2)S(2)O(8)) and hydrogen peroxide (H(2)O(2)) respectively to generate SO(4)˙(−) and ·OH for atrazine (ATZ) removal. The magnetic clay catalyst was characterized by XRD, SEM, N(2) adsorption–desorption and isoelectric point. The degradation efficiency of ATZ in the two systems was systematically compared in terms of initial pH, oxidant dosage and oxidant utilization rate. The results revealed that, after 90 minutes, systems with K(2)S(2)O(8) and H(2)O(2) can remove 65.7% and 57.8% of the ATZ under the given conditions (30 °C, catalyst load: 1 g L(−1), initial pH: 5, [ATZ](0): 10 mg L(−1), [H(2)O(2)](0): 46 mmol L(−1), [PDS](0): 46 mmol L(−1)). The magnetic clay catalyst still maintained good catalytic activity and stability during the four consecutive runs. Based on the quenching experiments, it was demonstrated that the dominant radical species in the two systems were SO(4)˙(−)/·OH and ·OH, respectively. However, the degradation efficiency of the two systems presented different responses toward the condition variations; the system with K(2)S(2)O(8) was relatively more sensitive to solution pH, the oxidant efficiency was generally higher than that of the H(2)O(2) system (except 184 mmol L(−1)).