Preparation Of TiO₂-acetylene-black Composite Photocatalyst And Photocatalytic Degradation Of Dye Waste Water

The organic pollutants existent in waste water can be degradated by the means of photocatalysis. As one of the most widely fascinating catalyst materials, titanium dioxide possesses many kinds of advantages, such as lower cost, non-toxicity, no photocorrosion, good stability and strong oxidative capacity; but some disadvantages, i.e., the low quantum transfer efficiency and the insufficient use of visible light have limited its application. In order to explore the photocatalysts with higher activity, the modification of titanium dioxide is studied. In recent years, carbon materials were impregnated into titanium dioxide photocatalysts and become a research focus since the pure titanium dioxide has limited adsorption and photocatalytic ability.Acetylene-black, a carbon material, has unique electrical properties and high specific surface area. In this study, titanium dioxide–acetylene-black nanocomposite photocatalyst was in-situ synthesized by sol-gel methods. By controlling the amount of titanium dioxide and the concentration of acetylene-black dispersions, titanium dioxide–Acetylene-Black composite with different acetylene-black content was prepared. The nanocomposites were characterized using TEM, XRD, UV–vis DRS and PL. As acetylene-black content increasing, the absorption intensity of visible light was increased. The results of XRD indicate that there only is titanium dioxide(anatase) particals in the composite. The absence of other diffraction peaks indicates that there was no new phase formation at the interface between acetylene-black and titanium dioxide. The average sizes of samples were estimated from the main peaks by scherrer’s equation, which were about 13.62 nm for titanium dioxide, and 11.98 nm for titanium dioxide–acetylene-black nanocomposite. Considering the result of fluorescence spectra, it was suggested that the acetylene–black can serve as electron traps and promote the electro-hole separation of titanium dioxide.The results showed that titanium dioxide–acetylene-black composite has better adsorption capacity and photocatalytic degradation efficiency for RHB(Rhodamine B), but for ARS(Alizarin red S) dyes only it photocatalytic degradation efficiency was improved. For 10 mg/L RHB, the adsorption capacity and photocatalytic degradation removal efficiency can reach above 98.5% with 5% titanium dioxide–acetylene-black dosage of 0.5 g/L under solar radiation. For 100 mg/L ARS, the degradation removal efficiency can reach more than 96% with 0.75% titanium dioxide–acetylene-black dosage of 0.5 g/L under solar radiation. The results showed that the loading of a certain amounts of acetylene-black had great influence on the photocatalytic activity of titanium dioxide. It is profitable for improving the photocatalytic activity of titanium dioxide by loading proper amounts acetylene-black in titanium dioxide.