Study On The Degradation Of Bisphenols In Water By Carbon-Nitrogen Nanomaterials Activated Peroxymonosulfate

The advanced oxidation technology based on persulfate has great potential in the degradation of typical refractory organic pollutants in water.Persulfate is divided into peroxymonosulfate(PMS)and peroxodisulfate(PS).Among them,PMS is easier to be activated due to the asymmetric structure.At present,commonly used PMS activation catalysts are metal-containing materials,which may cause secondary pollution due to metal leakage.Thus,the development of environmental friendly and efficient non-metallic materials is expected to promote the application of PMS catalytic oxidation technology in water treatment.In this paper,based on Schiff base chemical reaction,carbon nitrogen nanomaterials are prepared by improving the polymerization process of graphite carbon nitride(g-C₃N₄),and are used to activate PMS and degrade typical organic pollutants in water.The preparation process of the carbon nitrogen nanomaterials is simple.What's more,the carbon nitrogen nanomaterials have good performance on activating PMS to treat bisphenol A and bisphenol F in water,which has application potential.The research contents and conclusions are as follows:(1)The nitrogen-containing carbon nanomaterials are obtained by one-step thermal polymerization based on the interaction between urea and terephthalaldehyde.This method was based on the polymerization method of g-C₃N₄ and Schiff base chemistry.Compared with the process of urea polymerization to obtain g-C₃N₄,the addition of terephthalaldehyde inhibits the formation of melamine ring and promotes the production of cyano on the surface of nitrogen-containing carbon nanomaterials.The obtained nitrogen-containing carbon nanomaterials have high specific surface area,more active sites of graphite nitrogen.Moreover,the graphitization degree of the carbon nitrogen nanomaterials is significantly higher than g-C₃N₄.These properties enable the materials to exhibit good catalytic activity when used to activate PMS for treatment bisphenol A in water.According to the free radical capture experiment of the reaction process,singlet oxygen(¹O₂)is the main active species of this reaction system.(2)Based on the results of the previous part,the types of organic aldehydes are further expanded,and the effects of different types of aromatic aldehydes on carbon nitrogen nanomaterial produced by thermal polymerization of urea are discussed.The experimental results show that different kinds of aromatic aldehydes affect the polymerization process of urea.Compared with g-C₃N_4,the specific surface area of the obtained material is larger,the lamellar thickness is thinner,and the degree of graphitization is higher.Compared with the materials prepared by the precursor added 4-diethylaminobenzaldehyde and terephthalaldehyde,the carbon nitrogen nanomaterial prepared by the precursor added 2-naphthaldehyde has the best performance when used to activate PMS oxidation treatment of bisphenol F in water.And20 mg L^-1 bisphenol F was almost completely degraded within 30 minutes by 2NCN2 activating PMS.Singlet oxygen(¹O₂)was determined to be the main active species of the reaction system by free radical quenching experiment.