Graphene oxide-supported graphitic carbon nitride microflowers decorated by sliver nanoparticles for enhanced photocatalytic degradation of dimethoate via addition of sulfite: Mechanism and toxicity evolution

As pesticides are widely found in water, it is still a challenge to find an economical and effective technology to remove organophosphorus pesticides. Therefore, A composite with silver nanoparticles modified graphene oxide-supported graphitic carbon nitride microflowers ternary heterojunction (Ag@CNG) was synthesized by facile hydrothermal process. A novel composite system composed of photocatalysis and sulfite activation under visible light (Vis/Ag@CNG/sulfite) was constructed to realize the efficient removal of pesticides dimethoate (DT). Characterization results showed that the surface plasmon resonance (SPR) effect and ternary heterojunction could promote the photo-electrons transfer, and enhance the absorption of visible light. Moreover, the by-product sulfite added could be activated by holes to introduce novel SO4-, and obviously improve the decomposition of DT. Additionally, effects of operating parameters and supporting electrolyte on the degradation of DT were also detailed. Especially, the degradation pathways and mechanism of DT were revealed in depth through trapping experiments and GC-MS analysis combined with theoretical calculation. The toxicity evolution of products was also comprehensively evaluated. It was proved by degradation of different pollutants that the new composite system presented a great application potential for refractory and deleterious pollutants removal in water.