Thiol Deodorization Using Cu(II)/Ag(I)-Metal–Organic Gel-Based Photocatalyst in a Coiled Flow Inverter: Experimental and CFD Insights

Abstract

Abstract The combination of photochemistry and flow chemistry enables substantial improvement in reaction efficiency. By adopting this approach, the study focuses on the treatment of malodorous volatile thiols that pose serious environmental and health concerns due to their low odor thresholds and persistence in industrial and municipal waste streams. Photocatalytic oxidation offers a green and efficient route to transform thiols into benign disulfides (R–S–S–R), yet developing responsive, structurally adaptable photocatalysts, suitable for flow reactor systems remains a critical challenge. Herein, to address this issue, copper/silver-based metal–organic gels (MOGs) were designed for the sustainable catalytic conversion of thiols using a coiled flow inverter (CFI) photoreactor. Metallogels are composed of versatile organic scaffolds (KSM-1) and adenine (AD), which are complexed with intrinsic catalytic metallic ions, such as Cu2+ and Ag+. It is designed for the sustainable catalytic conversion of thiols using a CFI photoreactor. CFI offers superior process intensification compared to a straight, standard helical tubular reactor. By integrating equidistant 90° bends between helical modules, CFIs periodically invert the direction of fluid rotation and the direction of centrifugal force. These MOGs self-organize into a nanoporous catalytic interface within the CFI photoreactor, enabling light-driven (>400 nm) oxidative detoxification of thiol (R–SH) compounds into disulfides (R–S–S–R), as evidenced by UV–visible spectroscopy.