Enrichment and catalysis effect of 2D/2D g-C3N4/Ti3C2 for promoting organic matter degradation and heavy metal reduction in plasma systems: Unveiling the promotion and redox mechanism.

This work proposes a novel plasma-assisted 2D/2D g-C₃N₄/Ti₃C₂ system for treatment of organics-heavy metals composite wastewater. Unlike traditional materials in plasma system, 2D/2D g-C₃N₄/Ti₃C₂ not only improved the mass transfer efficiency of plasma by gathering both reactive species and pollutants onto the surface, but also induced photocatalytic reactions. Besides, the higher specific surface area and faster carrier separation rate can enhance the oxidation and reduction activity, and then promoted organic matter degradation and heavy metal reduction. Remarkably, the removal efficiency of sulfamethoxazole (SMX) and Cr(VI) increased by 16.5 % and 73.1 % respectively when introducing 2D/2D g-C₃N₄/Ti₃C₂. Roles of·OH,·H,·O₂^-, ¹O₂, e^-, and h⁺ in SMX oxidation and Cr(VI) reduction are clarified. The primary aggregated·OH and ¹O₂ dominate the degradation of SMX. The influencing factors, synergistic mechanism between plasma and catalyst, and redox mechanism were clarified. This work provides a breakthrough idea for treatment of organics-heavy metals composite wastewater.