As(III) removal by hydrous titanium dioxide prepared from one-step hydrolysis of aqueous TiCl4 solution

摘要

Hydrous titanium dioxide (TiO_2·xH_2O) nanoparticles were synthesized by a low-cost one-step hydrolysis process with aqueous TiCl_4 solution. These TiO_2·xH_2O nanoparticles ranged from 3 to 8 nm and formed aggregates with a highly porous structure, resulting in a large surface area and easy removal capability from aqueous environment after the treatment. Their effectiveness on the removal of As(III) (arsenite) from water was investigated in both laboratory and natural water samples. The adsorption capacity on As(III) of these TiO_2·xH_2O nanoparticles reached over 83 mg/g at near neutral pH environment, and over 96 mg/g at pH 9.0. Testing with a As(III) contaminated natural lake water sample confirmed the effectiveness of these TiO_2·xH_2O nanoparticles in removing As(III) from natural water. The high adsorption capacity of the TiO_2·xH_2O nanoparticles is related to the high surface area, large pore volume, and the presence of high affinity surface hydroxyl groups.