Electron-enriched supramolecular PDI-SiO2 promoting PDS activation for enhanced photocatalytic advanced oxidation

The efficient activation of peroxydisulfate (PDS) for wastewater treatment remains a great challenge. Photocatalysis, which generates highly-reactive electrons and holes, shows great potential in activating PDS for effective degradation and deep mineralization. Herein, an electron-enriched PDI-SiO2 photocatalyst was synthesized by covalently linking 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) onto silicon dioxide (SiO2) to form π-π stacked supramolecular PDI layers for efficient PDS activation. The highly dispersed PDI generates electron-enriched PDI·- under visible light, promoting the rapid activation of PDS for bisphenol A (BPA) degradation. The PDI-SiO2 activated PDS system realized a high BPA degradation rate of 0.100 min−1 and a remarkable mineralization rate of 81%. Moreover, the charge separation efficiency is significantly improved since the electrons of PDI·- are captured by PDS, boosting oxidative degradation and improving the mineralization efficiency. This work developed a novel PDS activation strategy by constructing electron-enriched photocatalyst, and revealed the mechanism of photocatalytic activation and deep mineralization.