The purification performance of S doped g-C3N4 photocatalyst with outstanding reduction efficiency over Cr(VI) under the actual underwater transmission light

Abstract

Cr(VI) existed in the industrial wastewater which has high biological toxicity has become one of the main pollution sources at present, and it is also difficult to remove from the wastewater because of its chemical stability. In this work, a raspberry-like sulfur doped carbon nitride photocatalyst (SCNx) with significant high reduction performance over Cr(VI) was prepared by solvothermal process. The BET data showed that the specific surface area of SCN4 was 3.75 times that of g-C3N4. Meanwhile, sulfur doping successfully reduce the band gap, which significantly improve the effective photoelectron density on the surface of the material, thus enhance its reduction ability. On this basis, the reduction activity of the SCNx to Cr(VI) in actual underwater environment was further investigated. Results show that SCNx still has good removal performance under weak light intensity and weak UV conditions. At 20 cm depth where ultraviolet spectral is attenuated 86.2%, the removal rate of SCN4 over Cr(VI) can still reach 58.1%. This research demonstrated that through S-doping and morphology control modification, carbon nitride can remain high photoreaction activity in the underwater weak light and weak UV environment, thus realize the efficient reduction treatment of Cr(VI). The research demonstrated the feasibility of heavy metal water treatment, and indicate a possible direction for the future practical application of heavy metal water purification.