Elaboration of the new heterostructure of NiAl2O4/kaolin and its photocatalytic activity towards methyl green under solar light irradiation

Abstract

Nanosized spinel NiAl2O4 was successfully supported on kaolin, natural support, by impregnation method; then tested as photocatalyst towards organic pollutant. The catalyst was characterized by IR spectroscopy, XR diffraction, BET, reflectance and XPS techniques. The photocatalytic tests were followed by UV-Vis spectroscopy for degradation of Methyl Green (MG) solution (C0=50 mg/L) under sunlight irradiation. The maximum adsorption (91.56 mg/g) of MG dye solution was observed for NiAl2O4 at an equilibrium time of 240 min; nevertheless, for NiAl2O4/kaolin, the equilibrium time was only 150 min for an adsorbed quantity equal to 45.78 mg/g. Some parameters influencing the dye adsorption were optimized. The fitting of the adsorption data for the Methyl green follows the Langmuir isotherm model. This new nanocomposite of NiAl2O4/kaolin exhibited excellent photocatalytic activity, which can degrade MG dye; mainly after adding the hole sensors (H2O2), within 90 min under sunlight irradiation.