• MATERIALS

    FORMATION OF NEAR-NANO SIZE TiB2-TiN-Al2O3 POWDER BY SHS

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 11, pg(s) 49-51

    Formation of TiB2 , TiN and Al2O3 powder mixtures were obtained through self-propagating high-temperature synthesis (SHS), starting from TiO2 + BN + Al mixtures. As a diluent, NaCl was added in 0-40 wt% range to the starting mixture in order to refine the size of the formed particles. Thermochemical calculations were performed by Factsage software. The products were subjected to XRD, SEM and particle size analyses. Intended reaction products were obtained in the TiB2, TiN and Al2O3 system according to XRD analyses, with no cross reaction products. The crystallite size of the products decreased with the increasing amount of NaCl according to the broadening of the peaks on the XRD patterns of the products. Particle size measurements revealed that near-nano size particles were formed. A decrease in the adiabatic temperature was calculated, a decrease in the velocity of the SHS wave front was observed and a decrease in the particle size of the obtained products was measured as a result of the increase in the diluent amount.

  • MATERIALS

    CoO/Al2O3, CuO/Al2O3 AND NiO/Al2O3 CATALYSTS FOR PHOTODEGRADATION OF MALACHITE GREEN DYE UNDER UV-IRRADIATION

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 8, pg(s) 30-33

    CoO, CuO or NiO supported on Al2O3 photocatalysts were prepared by impregnation and then calcination at 400oC for 3 hours. The obtained samples were physico-chemically studied by Powder X-ray diffraction analysis, X-ray photoelectron spectroscopy and Scanning electron microscopy. The photocatalytic oxidative degradation of aqueous solution of Malachite Green (MG) dye as pollutant using CoO, CuO or NiO supported on Al2O3 under UV irradiation was tested. The results determined that the highest degree of degradation of MG dye after 120 minutes was achieved using NiO/ Al2O3 photocatalyst (82%) than that the other materials CuO/Al2O3 (64%), CoO/Al2O3 (59%) and Al2O3 (50%). The calculated apparent rate constants increasing in the order: Al2O3 (2.7×10-3 min-1)<CoO/Al2O3 (3.9×10-3 min-1)<CuO/Al2O3 (4.1×10-3 min-1)<NiO/Al2O3 (8.4×10-3 min-1).