Preparation And Functionalization Of BiOCl Photocatalysts For Photocatalytic Degradation Of Organic Pollutants

With the fast industrialization and urbanization process,the production activities of human beings have produced a huge amount of polluted wastewater which have a great impact on the ecological environment and human beings.Typical polluted wastewater can be divided into organic and inorganic parts.Organic pollutants include dyes,drugs,and synthetic chemicals,while inorganic pollutants include heavy metal ions.Among different treatment techniques,photocatalytic advanced oxidation method shows the advantages of low energy consumption and mild reaction conditions.Considering the difficulty of recycle and strict light dependence,it is necessary to design specific functional materials to meet different needs.Meanwhile,solving the defects of photocatalysts has great scientific significance and is valuable in application for sewage treatment efficiency and photocatalysis technology.Based on the above topic background and research ideas,bismuth oxychloride?BiOCl?was selected as a representative photocatalyst to be functionalized and its photocatalytic performance and corresponding functionalization effects were studied in this dissertation.The main works and research results are as follows:?1?Low crystalline BiOCl was prepared by relatively convenient method assisted by mannitol complexation at room temperature and pressure.On this basis,thermally responsive BiOCl photocatalytic material loaded with poly?N-isopropylacrylamide??PNIPAM?was prepared using graphene oxide as a bridge.The as-prepared materials were characterized by XRD,XPS,DRS,UV-vis,PL and Raman.The adsorption rate constant of rhodamine B by low crystalline BiOCl was 0.2604 g·?mg·min?-1,which improved 5 times compared to high crystalline BiOCl nanoplates synthesized in hydrothermal method.Also,the photodegradation rate of composite functional materials was 7.26×10-2 min-1,7 times higher than high crystalline BiOCl nanoplates.The critical transition temperature of the functional material was tested through equilibrium swelling experiments.This functional material could settle down and separate quickly when aqueous temperature higher than critical transition temperature at 35? which is beneficial to convenient catalyst recycle use.The main photoactive species are superoxide radicals and hydroxyl radicals.Based on results of experiments,the possible reaction mechanism was discussed after detecting the hydroxyl radical and superoxide radical in photoreaction.?2?Functional catalytic oxidation BiOCl photocatalytic materials loaded with Co₃O₄ were prepared by hydrothermal and in-situ deposition.The materials were characterized by XRD,DRS,PL,photocurrent and electrochemical impedance spectroscopy.With the increase of the Co₃O₄ loading capacity,the photocatalytic performance of the functional material was improved first and then decreased.Among the as-prepared materials,the photodegradation rate of functional materials with the loading capacity of 1%wt was 0.58×10-1 min-1,owing the best photocatalytic performance.The catalytic oxidation performance of material was enhanced with the increasing of the Co₃O₄ loading capacity.The catalytic oxidation rates of potassium persulfate of 1.5%wt loading materials were 5.53×10-2 min-1.The results showed that the functional photocatalysts can degrade wastewater pollution under insufficient light conditions.Also,it maintained the excellent performance of photocatalysis which is helpful to improve the efficiency of the catalyst overall.