Research On The Application Of G-C₃N₄ Modified Catalyst In The Treatment Of Organic Pollutants

With the rapid development of industrialization,organic pollutants in industrial wastewater pose a huge threat to human health.Substandard wastewater contains endocrine disruptors,sulfur and nitrogen compounds,organic dyes,agrochemicals,pharmaceuticals and personal care products,causing widespread pollution of water bodies.Moreover,water shortages and increased water pollution have forced us to begin to develop efficient,practical and cost-effective water purification technologies.Traditional wastewater treatment includes biodegradation methods and physical and chemical processes(ozone,chlorination and flocculation,filtration and adsorption separation).These methods can treat most man-made wastewater.However,the above methods are less effective in degrading toxic chemicals(such as phenols,pesticides,dyes,and organic solvents).In recent years,the use of semiconductor materials and solar energy to degrade pollutants has received widespread attention.This paper mainly uses a combination of metal-free conjugated polymer semiconductor material g-C3N4 and advanced oxidation technology to degrade pollutants.The specific research content and results of the paper are as follows:1.The visible light/chlorine system can degrade organic pollutants,but due to the lack of light absorption and conversion matrix,the absorption efficiency of visible light is still very low.Based on this,we introduced g-C3N4,a non-metal semiconductor material with simple synthesis,low cost and low toxicity,into the solar/chlorine system.The addition of catalyst g-C3N4 into solar/chlorine system can significantly enhance the absorption and conversion of visible light and improve the degradation efficiency of CBZ.In this study,we first synthesized g-C3N4 in one step,and then combined g-C3N4 with the visible light/chlorine system(solar/chlorine/g-C3N4)to degrade the contaminant carbamazepine.The effect of sodium hypochlorite dosage,catalyst dosage,pH value of initial solution,anions in water and humic acid on the degradation performance was systematically studied.The production,effect and contribution of different active species in the visible light/chlorine/g-C3N4 system to the degradation of CBZ are clarified,and the pathway for O(3P)active species to degrade CBZ is proposed.2.In the traditional Fenton reaction,the homogeneous reaction solution formed by the added iron salt makes the catalyst difficult to separate from the reaction system,resulting in the ineffective recovery of Fe2+ and a large amount of iron slag.In order to recover Fe2+and improve the degradation efficiency,we synthesized FeCu-LDH/g-C3N4 as a solid catalyst for the Fenton reaction and used it to degrade rhodamine B.The effects of the molar ratio of iron and copper,the dosage of hydrogen peroxide,the dosage of g-C3N4 and the initial pH of the rhodamine B solution on the experimental results were systematically studied.TThe catalyst cycle experiment verified the high stability of the catalyst.This study provides a method to prepare an efficient and stable catalyst FeCu-LDH/g-C3N4,which can be used in Fenton reaction to degrade dyes.