Persulfate-enhanced degradation of propranolol over BiOCl0.5I0.5 under visible light irradiation

Abstract

The photodegradation of propranolol (PRO) by BiOCl_0.5I_0.5/persulfate under visible light was comprehensively investigated. The results demonstrated a significant increase in the removal efficiency of PRO under visible light irradiation, achieved by the combination of BiOCl_0.5I_0.5 solid solution and persulfate (PS). The photocatalytic activity of the system was found to be enhanced with an increase in the pH value. Additionally, the addition of a certain amount of PS improved the degradation of PRO. The presence of typical water constituents, Cl⁻ and NO₃⁻, had a negligible impact on PRO removal. In contrast, the increasing concentration of humic acid (HA) exhibited apparent inhibition of PRO degradation. Furthermore, radical scavenging experiments revealed that the removal of PRO was primarily facilitated by active free species, including h⁺ and ˙O₂⁻. The presence of characteristic peaks of ˙OH (peak ratio 1 : 2 : 2 : 1), ¹O₂ and ˙SO₄⁻ in the EPR spectrum indicates that these three radicals are also involved in the degradation process. Moreover, the BiOCl_0.5I_0.5/PS system demonstrated excellent photocatalytic activity, as well as favorable reusability and stability. This study offers new insights into the photocatalytic degradation of PRO, presenting a promising approach in this field.