Preparation and characterisation of titanium dioxide produced from Ti-salt flocculated sludge in water treatment
- Publication Type:
- Journal Article
- Journal of the Korean Industrial and Engineering Chemistry, 2009, 20 (3), pp. 241 - 250
- Issue Date:
During the past few years, titanium salts were investigated as alternative coagulants for the removal of organic matter of different molecular sizes in contaminated water. The flocculation efficiency of Ti-salt was comparable to those of FeCl3and Al2(SO4)3salts, commonly used coagulants. Incinerated sludge-TiO2showed higher surface area and photocatalytic activity than commercially available TiO2. Metal-doped forms were produced by adding coagulant aids such as iron (Fe-), aluminium (Al-) and (Ca-) calcium salts during Ti-salt flocculation to increase pH. Ca- and Al- doped TiO2showed very high photocatalytic activity compared to Fe-doped TiO2. When tested in a pilot scale plant for treatment of dye wastewater to check practical feasibility of the novel process, the removal ratio of the chemical oxygen demand was comparable to those of commonly used coagulants but the settling of sludge was faster. The TiO2generated after sludge incineration showed a high photocatalytic activity for degradation of volatile organic compounds and increased the rate of hydrogen production by water photosplitting. TiCl4coagulant and TiO2produced from different water sources with different concentrations had low acute toxicity compared to heavy metals and commercial TiO2when examined based on D. Magna mortality. This paper presents the production, characterisation and the photoactivity of TiO2produced from Ti-salt flocculated sludge. Different case studies are discussed to highlighted recent advances in this field.
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