Preparation and Characterization of Titanium Dioxide (TiO2) from Sludge produced by TiCl4 Flocculation with FeCl3, Al2(SO4)3 and Ca(OH)2 Coagulant Aids in Wastewater

Abstract

In this study, TiCl4 coagulant together with coagulant aids such as FeCl3, Al2(SO4)3, and Ca(OH)2 were investigated to improve the photoactivity of titanium dioxide (TiO2) produced from sludge and to increase the resulting low pH value. After TiCl4 flocculation with three coagulant aids, the settled floc (sludge) was incinerated at 600°C to produce TiO2 doped with Fe, Al, and Ca elements. Fe-, Al-, and Ca-doped TiO2 was characterized in terms of structural, chemical, and photo-electronic properties. All the coagulant aids used together with Ti-salt flocculation effectively increased the pH values. The surface area of TiO2-WO (without any coagulant aids), Fe/TiO2, Al/TiO2, and Ca/TiO2 was 122 m2/g, 77 m2/g, 136 m2/g and 116 m2/g, respectively. The TiO2-WO, Fe/TiO2, Al/TiO2, and Ca/TiO2 was found to be of anatase phase. The XRD pattern on the Fe/TiO2 included an additional peak of hematite (α-Fe2O3). The majority of gaseous acetaldehyde with TiO2-WO and Ca/TiO2 for photocatalytic activity was completely removed within 40 minutes under UV irradiation.