Multifunctional Sponge Enables the High-Efficient Photocatalytic Degradation of Dyes and Tetracycline through ZnS@Bi2S3@HNTs.

Photocatalytic technology has garnered considerable attention in wastewater treatment, but its application to complex wastewater remains challenged by particle aggregation and the difficulty of separating the catalyst from water. In this study, the heterojunction composite catalyst ZnS@Bi₂S₃ and halloysite nanotubes (HNTs) are immobilized onto a sponge substrate to enhance photocatalytic performance. SEM, XRD, XPS, FTIR, and UV-Vis analyses are conducted to characterize the morphology and evaluate the organic degradation performance of PPG/HNTs/ZnS@Bi₂S₃. The results show that the photocatalytic properties of ZnS@Bi₂S₃ are enhanced compared with ZnS. Incorporation of HNTs into PPG/HNTs/ZnS@Bi²S₃ further accelerates the adsorption of organic pollutants. PPG/HNTs/ZnS@Bi₂S₃ demonstrates outstanding photocatalytic degradation performance against various dyes (RHB, MO, MB), achieving efficiencies exceeding 98% and retaining over 73% efficiency after five consecutive catalytic cycles. The photocatalytic degradation efficiency of tetracycline (TC) reaches 97.3%. The photodegradation mainly originated from hydroxyl radicals. This method has potential for an efficient photocatalytic system in environmental remediation.