Characterization Of Nanosized TiO₂ On Glass Substrates And Studies Of Photocatalytic Degradation Of Dyes

As well known, dye wastewater is a trouble industrial wastewater due to its deep color, huge amounts, high CODo and BODs, as well as its difficult degradation by classic biodegration, biochemical degradation, physico-chemical degradation . In order to address this problem, extensive research is underway to develop advanced biochemical, and physicochemical methods for elimination of hazardous chemical compounds in dye wastewater.Semiconductor photocatalysis is to be considered as a supplementary to some approaches to the destruction of dye wastewater such as hightemperature incineration, amended activated sludge digestion, anaerobic digestion, and other physicochemical treatment. Semiconductors (such as TiC>2 ) can act as sensitizers for light-reduced redox processes due to their electronic structure. TiO2 has been used as a photocatalyst to degrade dye wastewater by ultraviolet radiation. The contaminants can be mineralized to CO2, P^O and other small molecules. Using TiC^ catalyst to photocatalytically degrade contaminants has many advantages, such as no secondary pollution, low operating and catalyst costs, being innoxious , fast , etc. This materials will be widely used in the protection of the environment wastewater treatment and air purification.The paper deals with (1) the photocatalytic mechanism of nanosized TiO2,(2) the prepare methode of nanosized TiO2 coating on glass substrates bysol-gel processing,(3) the characterization of nanosized TiO2 on glass substrates, and (4) studies of photocatalytic degradation for the methylene blue (MB)solution.It is feasible to prepare uniform transparent TiOa films from Ti(OC4H9)4-(C2H5O)2NH-C2H5OH-H2O system by sol-gel processing.The surface morphology of TiC>2 precursor films on the glass substrates (PTG) and nanosized Ti02 films on the glass substrates (NTG) have been characterized by TG, IR, UV, SEM and XRD. The results show that PTG and NTG have different morphology and component. The supposing process can be expressed as follows:The SEM studies of the coated TiO2 show that the diameters of the Ti02 particles on the glass sustrates are in the range 30-50nm.The photocatalytic activity of the anatase TiC>2 prevails over the rutile TiC>2.Photocatalytic degradation experiments indicated that photodegradation efficiency was enhanced with the increasing of the amount per unit area of NTG. The mechanism of the photocatalytic degradation of the methylene blue solution fits a first-order kinetic relationship well, and its rate constant (k) is 3.8 X10V.