Degradation of atenolol via heterogeneous activation of persulfate by using BiOCl@Fe 3 O 4 catalyst under simulated solar light irradiation

Abstract

Efficient oxidative degradation of pharmaceutical pollutants in aquatic environments is of great importance. This study used magnetic BiOCl@Fe₃O₄ catalyst to activate persulfate (PS) under simulated solar light irradiation. This degradation system was evaluated using atenolol (ATL) as target pollutant. Four reactive species were identified in the sunlight/BiOCl@Fe₃O₄/PS system. The decreasing order of the contribution of each reactive species on ATL degradation was as follows: h⁺ ≈ HO^· > O₂^·− > SO₄^·−. pH significantly influenced ATL degradation, and an acidic condition favored the reaction. High degradation efficiencies were obtained at pH 2.3–5.5. ATL degradation rate increased with increased catalyst and PS contents. Moreover, ATL mineralization was higher in the sunlight/BiOCl@Fe₃O₄/PS system than in the sunlight/BiOCl@Fe₃O₄ or sunlight/PS system. Nine possible intermediate products were identified through LC-MS analysis, and a degradation pathway for ATL was proposed. The BiOCl@Fe₃O₄ nanomagnetic composite catalyst was synthesized in this work. This catalyst was easily separated and recovered from a treated solution by using a magnet, and it demonstrated a high catalytic activity. Increased amount of the BiOCl@Fe₃O₄ catalyst obviously accelerated the efficiency of ATL degradation, and the reusability of the catalyst allowed the addition of a large dosage of BiOCl@Fe₃O₄ to improve the degradation efficiency.