Aquatic Ecotoxicity Effects of TiO2 Nanocrystals

Aquatic Ecotoxicity Effects of TiO2 Nanocrystals

A new and facile synthesis method of titanium dioxide (TiO2) nanoparticles (NPs) is presented in this work. This novel approach allows one to produce titanium dioxide nanoparticles owing to a modified solvothermal process that makes use of Titanium (IV) butoxide as the titanium precursor and Dimethyl Sulfoxide (DMSO) as a solvent. The structure and morphology of the TiO2 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX) and high-resolution transmission electron microscopy (HRTEM). Optical absorption measurement showed that the TiO2 nanoparticles exhibit a UV significant absorption peak clearly blue-shifted with respect to that of bulk TiO2. The results showed that monodisperse quasi-spherical TiO2 nanoparticles (with an average size of 11 nm) consisting of pure anatase phase were formed. To investigate the environmental impacts of the new synthesized TiO2 NPs, the oxidative stress in marine bivalves (Mytilus galloprovincialis) was assessed. No considerable effect was found in digestive gland in any of the treatment groups with TiO2 concentration gradients ranging from 0.1 to 100 mg/L. Thus, the level of the superoxide anion, the activity of an antioxidant enzyme superoxide dismutase (SOD) and the GSH/GSSG ratio showed no significantly differences in digestive gland of all treated groups compared to control. Whoever, slight modifications were observed in gill at high concentration (100 mg/L). These results demonstrated that the considered TiO2 appears to exert little toxicity on marine mussels after a short-term exposure at high concentration. The high crystalline quality, together with the easy synthesis process and limited environmental risk, makes the new TiO2 nanoparticles a promising candidate for many applications such as optoelectronics and water photolysis for hydrogen production.