PREPARATION, CHARACTERIZATION AND PHYTOTOXICITY OF TIO2 NANOPARTICLES

TiO(2) is being used in photocatalysis for its higher photocatalytic efficiency and chemical stability. TiO(2) in anatase form has band gap Eg=3.2 eV. Wavelenghts shorter than 390 nm (UV light) excite valence electrons to conductive band. One way for maximizing photocatalytic efficiency is modification of TiO(2) nanoparticles using noble metals. Using sol-gel method we prepared undopped and Ag dopped TiO(2) nanoparticles. Titanium tetraisopropoxide was used as TiO(2) precursor and silver nitrate as source of Ag, sodium citrate tribasic dihydrate was used as reduction agent. Precursors reacted in acidic solution under vigorous stirring at elevated temperature. Obtained white gel was dried and homogenized to powder. Samples were characterized using XRD, SEM. Photocatalytic activity was studied under UV and visible light irradiation by the means of acid orange7 discoloration. Acute toxicity test of prepared nanoparticles according to the OECD 201 algal growth toxicity test with organism Desmodesmus subspicatus. EC50 and NOEC values were determined. The EC50 value was higher for undoped TiO(2) than for Ag doped TiO(2) nanoparticles, which means higher toxic effect for Ag doped nanoparticles.