Metal-Free and Degradable Photocatalyst for Water Decontamination: An Innovative Application for High-Sulfur Content Polymers

This study explores high-sulfur content polymers as metal-free photocatalysts for water purification. Photocatalytic activity was strongly influenced by the chemical structure of the cross-linker; polymers with fewer unsaturations showed higher performance, while siloxane groups reduced activity by 81.3% by hindering hydroxyl radical generation. Increased sulfur content further improves photocatalytic activity, underscoring sulfur's role in contaminant degradation. The polymers achieved >80% removal of dyes and emerging contaminants, maintaining effectiveness in tap water, which demonstrates practical applicability. Reusability varied with cross-linker type, with 1,3-diisopropenylbenene (DIB)-based polymers showing lower durability than the 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane-based polymers. Importantly, DIB polymers underwent UV-induced oxidation and mineralization, reducing environmental persistence and minimizing secondary pollution risks. Overall, these high-sulfur polymers represent a promising, environmentally friendly alternative to conventional metal-based photocatalysts for sustainable water purification and treatment.