Preparation Of Carbon Nitride By Supramolecular Self-assembly And Photocatalytic Activity For Organic Pollutant

Treatment of organic wastewater has always been a difficult problem in the field of water purification due to its high cost,low efficiency,long processing cycle and possible second pollution.Nowadays,photocatalysis technology has been recognized as a promising and eco-friendly technology to decompose various organic pollutants for water environment purification,as it has giant potential for utilizing solar energy.The graphitic carbon nitride(g-C3N4)has been widely studied as a novel metal free semiconductor photocatalyst with a suitable band gap energy level.Meanwhile,it is hard,lightweight,non-toxic and easy to prepare.However,it also presents several negative features,including high recombination rates of charge carriers and low levels of electrical conductivity Therefore,the modification of g-C3N4 to improve its photocatalytic activity is of far-reaching significance.In this paper the metal-free modified carbon nitride MCU-CN(3:3:1)with a honeycomb-like morphology was prepared via firstly introducing cyanuric acid and urea into melamine in dimethyl sulfoxide as the precursor for the MCU-CN(3:3:1).A variety of characterization methods,including XRD,XPS,FT-IR,SEM,TEM,UV-vis,PL,and photocurrent generation,were applied to investigate the structure,morphology,optical,and photo electro chemical properties of the g-C3N4 and MCU-CN(3:3:1).Rhodamine B(RhB),methylene blue(MB),and bisphenol A(BPA)were selected as target pollutants to evaluate photocatalytic activity of the MCU-CN(3:3:1)under visible light irradiation.MCU-CN(3:3:1)exhibits significantly enhanced photocatalytic activity compared with g-C3N4,where 99.49%RhB is removed within 40min,97.7%MB is removed within 80 min,and 84.37%BPA is removed within 90 min.The improved photodegradation efficiency was mainly due to the larger surface area,the stronger REDOX ability,and the increased separation efficiency of photogenerated electron-hole pairs.The active radical trapping experiments and electron spin resonance tests indicated that h+and·O-2radicals were the dominant active species whereas·OH radicals could be a minor factor.A possible photocatalytic mechanism is proposed.This strategy here provides an ideal platform for the design of photocatalysts with large surface area and high porosity for various pollutant controlling applications.