Visible light-induced photocatalytic degradation of anticancer drugs via zeolitic imidazole framework (ZIF-8@ZIF-67): mechanistic insights

Abstract

An effective elimination of pharmaceutical pollutants offers a huge challenge for the conventional wastewater treatment system. In this study, the core–shell and reverse core–shell structures using zeolitic imidazole frameworks (ZIF-8 and ZIF-67) were prepared. Structural and morphological analyses were confirmed using XRD, RAMAN, XPS, and TEM techniques. The reverse core–shell structure (ZIF-8@ZIF-67) was explored as a photocatalyst for the efficient degradation of multiple classic anticancer drugs, including capecitabine (CAP) and 5-fluorouracil (5-FU), under visible light. This structure benefits from its unique design, offering a larger surface area and the intrinsic characteristics of each component. The synergistic interactions provide more accessible reactive sites, facilitate the diffusion of contaminants, enhance charge separation ability, and improve light utilization. Significantly, the optimized ZIF-8@ZIF-67 achieved a 98.4% removal rate of capecitabine (CAP) and a 97.4% removal rate of 5-fluorouracil (5-FU) under visible light in 120 min and 150 min, respectively, via the photo-reduction pathway, demonstrating superior photocatalytic performance. Various functional parameters, including catalyst dosage and pH effect, were thoroughly examined. Additionally, ZIF-8@ZIF-67 was recycled for five runs, with only a 10.8% of CAP decrease in degradation efficiency due to catalyst loss during washing. Therefore, ZIF-8@ZIF-67 not only exhibits superior photocatalytic performance but also maintains significant reusability. The findings of this study indicate that ZIF-8@ZIF-67 is a promising candidate for the effective removal of pharmaceutical pollutants from wastewater sources.

Graphical Abstract

Visible Light-Induced Photocatalytic Degradation of Anticancer Drugs via Zeolitic Imidazole Framework (ZIF-8@ZIF-67): Mechanistic Insights