Kinetic study of adsorption Eriochrome black T on La0.9Ca0.1CrO3−δ nano-oxid fabricated by sol-gel method

The structure of the LaMO3 perovskite oxide consists of MO6 and LaO12. A1−xA´xBO3−δ belongs to the group of perovskite oxides of the ABO3 structure with a trivalent rare earth in the A position (La) and a trivalent metal ion in the B position [1]In the present study, nanoparticles of perovskite-type La0.9Ca0.1CrO3−δ (LCCO) were fabricated by sol–gel method citrate technique .A series of analytical techniques were used to characterize the crystallinity, morphology, specific surface area and grain size of La0.9Ca0.1CrO3 powders. Thermal decomposition process of the complex precursor was examined by means of differential thermal analysis–thermal gravimetric analysis (DTA/TGA). X-ray diffraction (XRD) results showed that single perovskite phase has been completely formed after calcination at 750 °C. The surface morphology and composition of these nanopowders were also in vestigated using scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX). The calculated particles size using the Scherrer's formula was about 22 nm. LCCO nanoparticles showed the excellent adsorption efficiency to wards Eriochrome black T(EBT) as a reactive dye in aqueous solution. Experimental results indicated that the adsorption kinetic data follow a pseudo-second-order rate for tested dye. The isotherm evaluations revealed that the Freundlich model attained better fits to the experimental equilibrium data than the Langmuir model . Finally, the photocatalytic degradation of EBT using LCCO under solar light and UV irradiation at pH 2 was also investigated. The results showed that the nanoparticles cannot act as pure photocatalyst and the degradation of EBT dye follows only an adsorption process.

کلیدواژه ها:

Perovskite-type oxide ، Nanopowder ، Azo-dye removal ، Eriochrome black T ، Microscopic analyses ، Kinetic studies