Effect of calcination temperature on the characteristics of TiO₂ synthesized from ilmenite and its applications for photocatalysis

Titanium dioxide (TiO₂) contained in the Ilmenite Bangka mineral was synthesized by varying the calcination temperature to obtain characteristics that can improve the photocatalic ability. It can be a solution to handling of waste in the textile industry. Synthesis starts from a caustic fusion process using NaOH to decompose of ilmenite into the titanate compound were more soluble in acid, so that can reduce acid consumption in the leaching process. The leaching process uses 8 M H₂SO₄ in 5% solid to produce TiOSO₄ as a filtrate. Then the filtrate was hydrolyzed to obtain the precipitate TiO₂-Fe₂O₃. Calcination with variation of temperature was came after leached the precipitate with the water until neutral pH is obtained. The temperature used is: 350 °C (TiO₂ T₁), 450 °C (TiO₂ T₂), 550 °C (TiO₂ T₃), 650 °C (TiO₂ T₄), and 750 °C (TiO₂ T₅). The results of photocatalytic activity test using a solution of Rhodamin B (RhB) and Methylene Blue (MB) revealing that the highest photocatalyst efficiency was achieved by TiO₂ which calcined at a temperature of 650 °C, with 69.33% (RhB) and 83.41% (MB).Where in this temperature, rutile phase began to form about 15.38%, the band gap energy on 2.4 eV, and the growth of crystalite size become 53.41 nm which affected the increase in photocatalytic activity.