This book is about extracting titanium dioxide from ilmenite by acid leaching process and the application of it on degradation and solar cell. Nano composite of TiO2 synthesized from electrochemical method that is non expensive and very simple method to use in industrial work. TiO2 has a high risk material in many field to apply. It can be made from ilmenite by to acid leaching, first HCl then H2SO4. Both of them is suitable.