SYNTHESIS AND CHARACTERIZATION OF TiO2-ZnO BIMETALLIC OXIDE NANOCOMPOSITES FOR REMOVAL OF CHROMIUM FROM INDUSTRIAL WASTEWATER BY AAS.

<strong>Abstract</strong>: In the meantime, water contamination, especially heavy metals pollution inside water, has become a global environmental issue. Heavy metals could be released into water mainly through the mining, electroplating, metallurgy, chemical plants, agriculture and household wastewater etc. Various technologies that are currently used for the removal of heavy metals are evaporation, Ion exchange, precipitation, membrane filtration, and adsorption. Among all these technology adsorption process appears to be more favorable technology as it is low cost, require low maintenance, economical and is energy efficient. In all, the treatment of heavy metal in industrial wastewater is a great significance from the perspective of both the ecological environment and human health. Adsorbents which used to absorb the heavy metal ions on the surface of it can be prepared from different material’s. In this thesis TiO2:ZnO bimetallic oxides nanocomposite were used as the adsorbents. TiO2 were prepared from Titanium trichloride (TiCl3 15%, Merck) and NH4OH by co-precipitation methods. The precipitates were subjected to heat treatment with calcinations for 4 hours at the 900°C were obtained the yellowish colored TiO2 Nanoparticles. Also ZnO nanoparticles were prepared from the solution of Zinc sulfate heptahydrate (ZnSO4.7H2O) and ammonium hydroxide solution by direct precipitation methods. From these metal oxides, TiO2:ZnO bimetallic oxides nanocomposite were prepared. The removal efficiency of the adsorbent were tested at different ratios. The ZnO nanoparticles were used as the modifier of TiO2 nanoparticles. These prepared adsorbents were characterized by SEM-EDX and FT-IR. The morphology of the prepared adsorbent were determined by SEM and the elementary composition of prepared adsorbent were determined by EDX. The prepared TiO2 were contains 84.91% and 94.40% of Ti by wt.% and At.% respectively and 15.09 % and 5.60% 0f Oxygen bywt.% and At.% respectively. Prepared TiO2 were 100% of Ti and Oxygen with wt.% and At.% . The prepared ZnO were contains 43.00% and 75.5% of Zn by wt.% and At.% respectively and 57.00 % and 24.5% 0f Oxygen bywt.% and At.% respectively. Prepared ZnO were contains100% of Zn and Oxygen with wt.% and At.% . FTIR used to confirm functional groups present in the TiO2:ZnO(1:1)nanocomposites. The new peaks appeared in treated TiO2:ZnOnanocomposites spectra at 568cm-1 attributed to Ti-O-Zn bonds. The FTIR pattern of nanocomposites before and after adsorption should have a little difference b/n them. This shows the nanocomposites were reusable. The the initial concentration of cr in the waste water was 0.0565 mg/L and equilibrium concentration(concentration after adsorption) were 0.000539mg/L. This nanocomposites were99.046% efficient for the removal of chromium ions(specially cr(vi) from the industrial wastewater.