A series of bismuth oxybromo-iodide (BiOBr_xI_1-x; 0 ≤ x ≤ 1) solid solutions were synthesized and screened to identify the best composition for the photocatalytic degradation of representative pharmaceutical and personal care products (PPCPs), which was found to be BiOBr_0.9I_0.1. Subsequently, its magnetic version (BiOBr_0.9I_0.1/Fe₃O₄@SiO₂) was solvothermally developed to achieve magnetic recoverability from secondary treated sewage. The visible-light-driven superparamagnetic BiOBr_0.9I_0.1/Fe₃O₄@SiO₂ photocatalyst had a 3D micro-spherical form with a mesoporous hierarchical morphology. Almost complete photocatalytic degradation of two model PPCPs, ibuprofen and benzophenone-3, was achieved in 1 and 2 h, respectively. Reactive species’ scavenger-based mechanistic analysis revealed that ibup...[ Read more ]

A series of bismuth oxybromo-iodide (BiOBr_xI_1-x; 0 ≤ x ≤ 1) solid solutions were synthesized and screened to identify the best composition for the photocatalytic degradation of representative pharmaceutical and personal care products (PPCPs), which was found to be BiOBr_0.9I_0.1. Subsequently, its magnetic version (BiOBr_0.9I_0.1/Fe₃O₄@SiO₂) was solvothermally developed to achieve magnetic recoverability from secondary treated sewage. The visible-light-driven superparamagnetic BiOBr_0.9I_0.1/Fe₃O₄@SiO₂ photocatalyst had a 3D micro-spherical form with a mesoporous hierarchical morphology. Almost complete photocatalytic degradation of two model PPCPs, ibuprofen and benzophenone-3, was achieved in 1 and 2 h, respectively. Reactive species’ scavenger-based mechanistic analysis revealed that ibuprofen’s degradation was dominated by e^-, •O₂^-, and h⁺, while the degradation of benzophenone-3 was dominated by e^- and •O₂^-. PPCPs’ degradation pathways were proposed based on mineralization and intermediates analyses, while the aquatic toxicity of the detected intermediates―estimated using the ECOSAR software of USEPA―was lower than that of the parent PPCP molecules, indicating a reduced environmental risk after the photocatalytic degradation. The effects of solution matrix (pH, anions, cations, and natural organic matter) were examined, while the practicality was evaluated by studying the reusability and stability of BiOBr_0.9I_0.1/Fe₃O₄@SiO₂ in secondary treated sewage, over multiple cycles, in a specifically designed prototype photocatalytic reactor integrated with a magnetic separator. The degradation performance gradually decreases, which is attributed to the interference effects of different constituents present in sewage with the photocatalyst.