Study On Application Of New Photocatalyst Based On Biological Template To Degradation Of Organic Wastewater

With the rapid development of industry,manufacturing and production industry in modern society,various environmental problems have become increasingly prominent,among which water environment is closely related to the survival and development of human beings.Water pollution is one of the main problems facing human beings at present.The water pollutants discharged by industry,manufacturing industry and other industries are more and more diversified.It is difficult to be degraded by traditional water treatment technology in the natural environment,which is undoubtedly a great challenge.In the past few decades,semiconductor photocatalytic technology has attracted extensive attention and research because of its advantages of green,economic and sustainable development.Therefore,how to obtain high efficiency,reliable and stable performance of photocatalytic technology has become the focus of research.Based on the above content,we mainly carry out the following three aspects of research in this paper:1.Using bismuth nitrate pentahydrate（Bi（NO₃）₃·5H₂O）as bismuth source and cetyl trimethyl ammonium bromide（CTAB）as bromine source,a series of C-doped Bi OBr photocatalysts with different morphs and structures were prepared by hydrothermal method by changing the ratio of anhydrous ethanol and water dissolved Bi（NO₃）₃·5H₂O.Combined with the test results of various structural characterization,the differences of Bi OBr under different preparation conditions were analyzed.The optimal sample（CB-2）screened by degradation of simulated pollutant ciprofloxacin（CIP）can achieve 90%CIP degradation efficiency of30mg/L,and its repeated degradation performance is excellent.After 5cycles of degradation,the overall removal rate of pollutants can still reach 80%.2.The mixture solution of anhydrous ethanol and tetrabutyl titanate（TBT）was used as the precursor solution in a ratio of 3∶2,and corn straw was used as the biological template.Soaking,ultrasonic oscillation and microwave assisted methods were used to make Ti O₂ grow on corn straw,and the corn straw template was removed by conventional calcination.The effect of different template removal temperatures on the formed Ti O₂ was studied,and the morphology characterization of the samples generated at different temperatures was analyzed.Among them,the sample（BT-2）that removed the template at 450℃for 15h had the best photocatalytic performance,and its overall removal rate of CIP reached70%,which was about 50%higher than that of the commercial Ti O₂.However,its repeated degradation performance is poor,and the overall removal rate of pollutants is only about 40%after three cycles of degradation.3.Using the stable and reliable solvothermal method,combined with the above C-Bi OBr preparation method,BT-2 sample was added into the precursor solution,and the amount of BT-2 sample was changed to prepare Bi OBr/Ti O₂composite photocatalyst with different content ratios.When the amount of BT-2was 0.1g,the photocatalytic activity of the sample prepared（TB-2 sample）was the strongest,and the overall removal rate of pollutants was the highest,up to 92%,which was 2%and 22%higher than that of CB-2 and TB-2 samples,respectively.Cyclic degradation experiments showed that the photocatalytic activity of TB-2 sample decreased significantly after three rounds of degradation,and was close to that of BT-2 sample,which did not show good recycling performance.According to the experimental results of thermal catalysis,the photocatalytic degradation caused by the irradiation of light source is the main reason for the reduction of pollutant concentration,and thermal catalysis does not promote the photocatalytic degradation.Free radical quenching experiments showed that superoxide radical（-O₂）and photogenic hole（h⁺）were the main active species in the photocatalytic degradation of CIP using CB-2,BT-2 and TB-2 samples.