Study On The Preparation Of Modified TiO₂and Its Photocatalytic Degradation Of Organic Wastewater

In recent years, there is increasing number of researchers pay attention to the modification of TiO2by codoping. Although TiO2has a lot of merits on photo-catalytic degradation, it exist some drawbacks on practical use such as inefficient recovery and low quantum efficiency limited available sun energy spectrum range. The paper aimed to enhance the photoactivity TiO2by codope.This paper researched the degradation methyl orange dye by composite catalysts of TiO2in order to discuss the effect of CdS/ZnS/TiO2、AC/SiO2/TiO2in photocatalytic degradation.The study used CdS/ZnS/TiO2to degrade the methyl orange dye and investigated the impact factors of photochemical reaction such as the number of the composite proportion, temperature and time of the heat treated, initial pH and catalyst dosage. The structure and the morphology, the properties and absorbency were researched by XRD, TEM and UV-Vis absorption.By the research, the optional preparing condition of CdS/ZnS/TiO2was obtained: XS (CdS, ZnS):TiO2=1:100; CdS:ZnS=1:1; calcined temperature:500℃; calcined time:1h. During the photochemical reaction, it was achieved the best result when the concentration of solution was20mg/L, pH=5-7and the catalyst dosage was2g/L. The best rate of decoloration and TOC removal was84.3%and54.2%by using CdS/ZnS/TiO2under the Vis irradiation, which is also higher then the result by using TiO2、CdS/TiO2and ZnS/TiO2.Then, AC/SiO2/TiO2can acquired the best result for using the following preparing condition:SiO2:TiO2=l:3; doping amounts of AC=20%; calcined temperature:500℃; calcined time:2h. During the photochemical reaction, it was achieved the by result when the concentration of solution was20mg/L, pH=3-5and the catalyst dosage was2.7g/L during100min. The best result of decoloration rate was93.3%by using AC/SiO2/TiO2under the ultraviolet irradiation.