Effect Of Adsorption On The Performance Of Supported ZnO Catalysts For Photocatalytic Degradation Of Organic Pollutants

In this paper,the adsorption of organic pollutants and oxygen-containing substances on the surface of supported photocatalysts and their effects on the photocatalytic degradation of organic pollutants were studied,and the efficient and economical catalyst regeneration methods and photocatalytic operation methods were explored to further improve the efficiency of photocatalytic degradation of organic pollutants.ZnO/AC and ZnO/SBA-16 supported photocatalysts were prepared by sol-gel method and impregnation-calcination method,respectively.The effects of catalyst preparation conditions such as mass ratio of semiconductor to carrier,calcination temperature,photocatalytic reaction conditions such as initial pH of solution and dark adsorption time on the adsorption of MO by ZnO/AC and ZnO/SBA-16 and the relationship between different adsorption effects and photocatalytic degradation performance were investigated.The results showed that only when the adsorption process of the catalyst to the organic matter is the rate-controlling step of the photocatalytic process,strengthening the adsorption performance of the catalyst to the organic matter can improve the efficiency of photocatalytic degradation of the organic matter.By changing the pH and dissolved oxygen content of the solution,the adsorption performance of the supported photocatalyst on oxygen-containing substances and its effect on the photocatalytic degradation of organic matter were explored.The results showed that the adsorption of OH^-and O₂on the surface of the catalyst can promote the formation of active substances such as·OH and·O₂^-,and improve the photocatalytic activity.The photocatalytic degradation rate of MO by ZnO/AC and ZnO/SBA-16 can reach 100%,and the TOC removal rate can reach more than 90%in a certain time,which is nearly 20%higher than the reported photocatalytic degradation rate of MO.Based on the strong adsorption performance of the supported photocatalyst,a new photocatalyst regeneration method and a new photocatalytic operation method were explored.The results showed that the degradation rate of MO and the removal rate of TOC by ZnO/AC were 96%and 80%,respectively,after five cycles of the catalyst regenerated by light method for five times.The photocatalytic operation method using adsorption+light catalyst can reach 100%photocatalytic degradation rate of MO,the removal rate of TOC can reach 96%,and the photocatalytic reaction time is shortened by nearly 20 min.