Photocatalytic degradation of crystal violet dye under sunlight by chitosan-encapsulated ternary metal selenide microspheres.

Organic dyes that are extensively released in wastewater from various industries remain the priority concern in the modern world. Therefore, a novel catalyst, bismuth-iron selenide, was prepared through the solvothermal process for photocatalytic degradation of a carcinogenic crystal violet dye. The catalyst was supported with chitosan to form iron-bismuth selenide-chitosan microspheres (BISe-CM). The synthesized catalyst was composed of iron, bismuth, and selenium in a definite proportion based on EDX analysis. FTIR analysis confirmed the synthesis of BISe-CM from characteristic bands of metal selenium bond as well as the typical bands of chitosan. SEM analysis illustrated the average diameter of the barren catalyst to be 54.8 nm, while the average size of the microspheres was 982.5 um. The BISe-CM has the surface of a pore with an average size of 0.5 um. XRD analysis revealed that the synthesized catalyst was composed of Fe3Se4 and Bi2Se3. The prepared catalyst showed better degradation efficiency for crystal violet dye at optimized conditions under solar irradiation. Employing 0.2 g of BISe-CM resulted in complete degradation for 30 ppm of crystal violet dye in 150 min at pH 8.0. The reusability of the catalyst up to four consecutive times makes it a more attractive and practical candidate. Moreover, the catalyst followed pseudo-first-order kinetics in the decontamination of crystal violet. Conclusively, the novel photocatalyst showed the best decolorizing property of crystal violet under sunlight irradiation and could be a suitable alternative for dye decontamination from wastewater.