Multi-phase CdS loaded on biochar for photocatalytic activation of peroxymonosulfate for thiamethoxam degradation: p-conjugation improves PMS adsorption

Mounting evidence highlights the negative impacts of thiamethoxam (THM) on non-target organisms and ecosystem. Herein, multi-phase cadmium sulfide loaded on biochar (CdS@BC) was used to photocatalytic activate peroxymonosulfate (PMS) to remove THM. The obtained CdS@BC significantly improved the photocatalytic performance of PMS on THM degradation with a superior rate constant of 0.165 min-1, 60 times more than that of BC. In addition, the catalyst displayed excellent stability and reusability. The mechanism of free radical formation by adsorption activation of PMS adsorbed on CdS@BC was characterized using active species detection and Density functional theory (DFT) calculations. According to the DFT study, the phase junction and & pi;-conjugated structure contribute to the stable migration of & pi;-electrons, thus effectively activating the PMS to produce active substances for the degradation of THM. The findings provide a theoretical basis for the design and synthesis of effective catalysts for AOPs to remove emerging organic contaminants from wastewater.

Automated summary

This study investigated the use of multi-phase cadmium sulfide loaded on biochar as a catalyst to activate peroxymonosulfate for the removal of thiamethoxam. The results showed that the catalyst exhibited excellent photocatalytic performance and stability. The mechanism of free radical formation during the activation process was characterized using theoretical calculations and experimental characterization.