Spiropyran-decorated advanced photoswitchable materials for Bisphenol A removal

In this study, a novel dual-molecule system made of spiropyran-loaded magnetite is designed and synthesized in the laboratory for the degradation of Bisphenol A. Comprehensive chemical, morphological, structural, photo-responsive, and cytotoxic examinations show that the smart material has been successfully functionalized and acts as a highly active catalyst. Spiropyran-loaded magnetite nanoparticles demonstrate efficient singlet oxygen generation (approx. 59 µM of ¹O₂ in only 60 min) while maintaining sustainable operational parameters, offering a promising alternative to conventional advanced oxidation process-based systems. At a catalyst loading of 1 g/L, all photodegradation reactions followed pseudo-first-order kinetics, with apparent rate constants (k) in the range of 0.0078–0.1549 ± 0.0007 min⁻¹ (R 2 > 0.989). Moreover, the photocatalyst was successfully used in four consecutive runs, without significant loss of catalytic activity. In agreement with photocatalytic oxidation data, the cytotoxicity results showed that during the photocatalytic reaction, the samples were less cytotoxic. Based on the obtained results, among the organic molecules used as photosensitizers, spiropyrans hold great promise for the development of smart photocatalysts.