Preparation and application of nano-TiO2 catalyst in dye electrochemical treatment

This paper reports results of an investigation into the removal of ARB (Acid Red B) dye in an electrochemical oxidation reactor with semi-conductor suspended in the electrolyte. TiO2 nano-powders spiked with various elements, including Si, Co, Zn, La, Ag, Ce, W and Bi, were prepared by sol-gel method to improve colour removal efficiency. Through the L16(4 4) orthogonal experiment, the optimised preparation conditions of nano-TiO2 catalyst were obtained, namely prepared at 400oC and spiked with 10% Co(in molar ratio). The XRD (X-ray diffraction) analysis indicated that TiO2 prepared at 400oC occurred predominantly in the anatase crystalline form and the particle size was below 20 nm. The BET (Brunauer, Emmet and Teller) surface area was 69.2m2/g. The decolourisation efficiency using Co (10%)/TiO2 as catalyst was 33.1% and increased by 5.7% (about 1.21 times) compared with the colour removal without catalyst. The DRS (diffuse reflectance spectroscopy) demonstrated that the improvement of colour removal of Co(10%)/TiO2 compared with pure TiO2 was probably due to its better light absorption and photocatalytic activity in the visible region.