Al,Fe,Ni-pillared bentonite in the catalytic wet peroxide oxidation of the textile dye Acid Yellow 99

Abstract

The main goal of this work was to prove that nickel containing Al,Fe pillared bentonites have enhanced catalytic properties. The chosen test system was the catalytic wet peroxide oxidation (CWPO) the Acid Yellow 99 dye (AY99) with the initial concentration of 50 mg dm−3, the amount of H2O2 that exceeded the stoichiometric one, 60 °C, magnetic stirrer, atmospheric pressure. Bentonite was successfully pillared with AlFe and AlFeNi polyoxo cations. The chemical composition of the synthesized samples was: SiO2 56.5, Al2O3 31.3, Fe2O3 9.2; SiO2 56.4, Al2O3 31.9, Fe2O3 8.9 and NiO 0.1; SiO2 61.1, Al2O3 31.3, Fe2O3 4.8 and NiO AlFe10Ni5-PILC > AlFe5Ni5-PILC. Almost complete decolorization was achieved using all synthesized catalysts and followed first order kinetics. AlFe10Ni5-PILC induced the highest decolorization rate. Somewhat higher decolorization rate in the presence of AlFe10Ni5-PILC in comparison with AlFe5Ni5-PILC can probably be ascribed to one of the following properties or their combined effect: higher Fe content and more developed porous structure. Adsorption of AY99 on AlFe5Ni5-PILC and its degradation by H2O2 (without catalyst) were investigated in order for their influence on the decolorization of AY99, in comparison with that of CWPO using AlFe10Ni5-PILC, to be estimated. The adsorption was the least efficient, followed by degradation using H2O2 (without catalyst). CWPO was more efficient when compared to adsorption and degradation by H2O2 together. CWPO using Al,Fe,Ni-PILC can be regarded as promising method for degradation of azo dyes.