OICC Press Journal of Nanostructure in Chemistry 2193-8865 5 1 (March 2015) 2014 12 10 Synthesis of TiO2 nanopowders from red gypsum using EDTA as complexing agent 10.1007/s40097-014-0137-7 EN M. Z. Borhan Environmental Research Technology Centre (ERTC), Shah Alam, Selangor Darul Ehsan, 40700, MY T. Y. Nee Environmental Research Technology Centre (ERTC), Shah Alam, Selangor Darul Ehsan, 40700, MY Journal Article 2014 12 10 Abstract TiO 2 white pigments were used in various applications due to their magnificent optical and electronic properties. In this paper TiO 2 was recovered from red gypsum which is a waste generated at TiO 2 production industry. The effect of time and temperature in sulphuric acid leaching processes was optimized. TiO 2 powders were synthesized through thermal precipitation process with the presence of ethylenediaminetetraacetic acid as a complexing and purification agent. The obtained powders were characterized by X-ray diffraction, transmission electron microscope, UV–Vis spectroscopy and inductively coupled plasma optical emission spectroscopy. Experimental results show that powders in anatase form have a 3.2 eV band gap with a crystallite size 30–50 nm.