Preparation of mesoporous TiO2-SiO2 and photocatalytic degradation of black liquor

In this paper, mesoporous TiO2-SiO2 photocatalysts (with different ratio of Ti/Si) was successfully synthesized by using nonionic triblock copolymer (P123) as template agent via sol-gel reactions of tetrabutyl titanate (TBOT) and tetraetethyl orthosilicate (TEOS), followed by removing the template through ethanol extraction and calcinating at 400 center dot for 4 h. The photocatalytic degradation of black liquor under mesoporous TiO2-SiO2 was investigated in aqueous suspensions of the resultant products by monitoring the depletion of chemical oxygen demand (CODCr) content as a function of irradiation time under a variety of conditions. The influencing factors on the degradation of black liquor such as the catalyst, irradiation application time, catalyst dosage, initial pH value, aerating mode etc. in the photocatalysis system were investigated. The results showed that the presence of SiO2 (Ti/Si = 100:1) in mesoporous TiO2 crystal can improve the activity of TiO2 and the optimal degradation effect was achieved when the catalyst (Ti/Si=100:1) dosage was at 1.5g/L and the initial pH = 6 with continuous aerating, which the CODCr removal rate for the black liquor reached 94.9% after 12 h irradiation.