Photocatalytic Degradation Of Tetracycline Hydrochloride In Water By TiO₂/Zeolite

Tetracycline hydrochloride is an antibiotic with a stable naphthol ring structure,potentially toxic to humans,and some of its degradation byproducts are more toxic than the parent and are difficult to remove by conventional treatments.TiO2 advanced oxidation technology has been becoming a latest field of waste water treatment technology.However,nano-TiO2 is difficult to recover,and the cost is high.Therefore,The degradation of tetracycline hydrochloride in water by high efficiency and easy recovery of photocatalyst has become one of the new research hotspot.In this study,zeolite-supported TiO2 photocatalyst was prepared by sol-gel method.The composition,morphology and structure of the composite photocatalyst were characterized by XRD,SEM,FTIR and Raman Spectrum.The effects of TiO2/zeolite composite photocatalyst on the degradation of tetracycline hydrochloride in water were discussed in detail.The removal efficiency of tetracycline hydrochloride by pure TiO2 Which was prepared by the same method was compared.Get the following conclusions:(1)To zeolite as carrier,TiO2/zeolite composite photocatalyst was successfully prepared by sol-gel method and butyl titanate as raw material at high temperature calcination at 450 ?.(2)The results show that TiO2 has been successfully supported on the surface of zeolite and exists in anatase form.Making the composite catalyst easy to separate recycling.The surface of the composite catalyst is closely covered with a layer of TiO2 film,and its surface is scattered with a large amount of TiO2 particles,which increases the roughness and specific surface area of the zeolite.(3)When the dosage of TiO2/zeolite composite photocatalyst was 4 g/L,the concentration of tetracycline hydrochloride was 20 mg/L,pH = 4.47,reaction was adsorbed for 30 min in the dark,UV irradiation was 120 min,the removal rate can reach 91.7%,H2O2 and complex photocatalyst synergies is conducive to the removal of tetracycline.(4)Under the same conditions,40W UV(light intensity of 4.9 × 104 W/m3)irradiation,pure TiO2 on the removal of tetracycline hydrochloride is better than TiO2/zeolite composite photocatalyst.However,the effect of TiO2/zeolite composite photocatalyst on the removal of tetracycline hydrochloride was almost the same as that of pure TiO2 under the irradiation of sunlight in early August.(5)In the study of the stability of TiO2/zeolite composite photocatalyst,it was found that the removal rate of TiO2/zeolite composite photocatalyst was about 80%when it was repeated four times,and it had good stability.After five times,the removal rate dropped to 65.37%,it can not be used indefinitely,the stability still needs to be improved.(6)TiO2/zeolite composite photocatalyst has similar kinetic curve with pure TiO2,and it has a good linear correlation with the degradation trend of tetracycline hydrochloride,which is in accordance with the first order reaction kinetics model.