Carbon nanotubes functionalized with titanium complexes for hexavalent chromium adsorption: An ab initio approach

Abstract

This work presents an original study of the structural and electronic properties of doped single-walled carbon nanotubes (SWCNT) through titanium complexes and the possibility of adsorption and reduction of hexavalent chromium Cr(VI) using density functional theory. Cr(VI) is one of the major environment pollutants, its removal presents several difficulties, and it results in industrial pollution, causing health problems. The adsorption of Cr(VI) was investigated from the chromate and dichromate molecules in semiconductor SWCNT functionalized with TiO2, TiO4H4 and Ti2O6H4 complexes. The results suggest that the functionalized SWCNT are great candidates to adsorb Cr(VI) from the environment, because of their structural diversity, large specific surface area, small size, good chemical stability, low density, possible regeneration and reusability. In addition, the electronic band structures changed in the region near the Fermi energy of the valence and conduction bands for the pristine and functionalized SWCNT with chromium systems. After adsorption of Cr(VI) in the systems, the formation of molecules with less toxicity and carcinogenic activity is observed.