Enhanced photocatalytic degradation of polyethylene terephthalate microplastic via BiOCl0.5I0.5 solid solution-mediated activation of H2O2
Source abstract
Abstract
Polyethylene terephthalate (PET) microplastics (MPs) exhibit high chemical stability, limiting their degradation under mild environmental conditions. Herein, a visible-light-responsive BiOCl 0.5 I 0.5 solid solution was synthesized and evaluated for the oxidative degradation of PET MPs in an aqueous H 2 O 2 -assisted system. Structural analyses confirmed successful halide substitution and lattice distortion, while UV–Vis diffuse reflectance spectroscopy revealed bandgap narrowing (2.07 eV) relative to BiOCl, extending visible-light absorption. Photoluminescence and electrochemical impedance spectroscopy demonstrated improved charge separation in the mixed-halide system. Mott–Schottky analysis revealed a sufficiently positive valence band potential to drive the oxidation of H 2 O/OH⁻ to •OH radicals. Under visible-light irradiation (425 nm), the combined BiOCl 0.5 I 0.5 /H₂O₂ system achieved a maximum PET mass loss of 41.0% after 48 h at pH 10, outperforming photolysis and single-component controls. ATR-FTIR, TGA, and SEM analyses indicated ester bond cleavage, reduced thermal stability, and pronounced surface erosion consistent with oxidative chain scission. LC–MS detected soluble intermediates including mono(2-hydroxyethyl) terephthalate (MHET) and terephthalic acid derivatives, suggesting progressive depolymerization and oxidation. Taguchi experimental design and ANOVA identified pH as the dominant operational parameter, followed by light intensity, whereas H 2 O 2 concentration showed a comparatively minor effect within the investigated range. The enhanced performance is attributed to the synergistic generation of hydroxyl and superoxide radicals via photocatalytic activation and H 2 O 2 -reduction pathways. This study demonstrates the potential of bismuth oxyhalide solid solutions for photo-assisted PET microplastic degradation and highlights the importance of coupled chemical–photocatalytic conditions in accelerating polymer breakdown.
Source: openalex_inverted_index · Quality: baseline
Research context
OpenAlex topics: Advanced Photocatalysis Techniques · TiO2 Photocatalysis and Solar Cells · Nanomaterials for catalytic reactions
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
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