Preparation Of GC₃N₄ Composite Material And Its Photocatalytic Degradation Of Organic Pollutants

Our country is an area where industrial,agricultural and medical supplies are frequently produced and used.The serious harm pollution of the water environment has been caused by chlorophenol and antibiotics.These pollutants have long half-life and highly persistent nature.It can cause a serious impact on the human body through the accumulation in the ecological environment.Therefore,the simple and effective pollutant degradation methods must be found.As a green methods using renewable energy,photocatalytic degradation has received widespread attention.As an environmental friendly non-metallic semiconductor photocatalyst,graphite nitride carbon?g-C₃N₄?can efficiently remove contaminants from the water,but the high recombination rate of photogenerated carriers limits its photocatalytic activity.In this paper,hydrothermal,co-precipitation and reduction methods were used to synthesize the composites with g-C₃N₄ as the main materials,respectively,and the structure of the prepared materials were characterized.Selecting 2,4-DCP and SMT as target analytes to test the photocatalysis performance of the synthesized composites,and the effect of external experimental conditions on photocatalytic degradation efficiency were investigated.In addition,the mechanisms of photocatalytic oxidation were also discussed.The results are as follows:1.ZnNb₂O₆/g-C₃N₄ photocatalysts were synthesized by hydrothermal method for 2,4-DCP photodegradation.ZnNb₂O₆ was uniformly deposited on the surface of g-C₃N₄.After 180 min il umination,when the mole rate of ZnNb₂O₆ and g-C₃N₄ was 1:7,solution pH was 7,the concentration was 10 mg·L^-1 with 0.4 g·L^-1 dosage of composites,the removal rate could reach 95.7%.The study of mechanism shows that ZC-7 is Z-scheme heterojunction nanomaterial.2.Bi₄MoO₉/g-C₃N₄ composites were synthesized by hydrothermal method and then applied to photocatalytic degradation of SMT.Under 180 min irradiation,with the condition of Bi₄MoO₉ and g-C₃N₄ mass ratio was 1:1?BMC-50?,the catalyst dosage was 0.5 g·L^-1 and the SMT initial concentration was 10 mg·L^-1,more than 90.0%SMT can be photodegraded.After multicycles of BMC-50 composite,its catalytic performance is not significantly decreased,indicating that the material has good structural stability.The photodegradation performance was improved by the formation of heterostructure.3.Bi-BiVO₄/g-C₃N₄ composites were synthesized by a three-step method and applied to the photodegradation of SMT.The SMT removal rate reached 93.6%with system pH of 7.04,the catalyst dosage of 0.5 g·L^-1 and the concentration of 10 mg·L^-1.This is due to the surface plasmon resonance?SPR?effect after NaBH₄ reduction,which improves the interface electron migration efficiency and the catalytic activity of Bi-BiVO₄/g-C₃N₄ composites.