SYNTHESIS, CHARACTERIZATION AND EVALUATION OF THE CATALYTIC ACTIVITY OF NIOBIUM COMPOSITE/CLAY ON OXIDATION REACTIONS
composite; vermiculite; bentonite; photocatalytic oxidation; niobium oxyhydroxide; AOP
The textile industry generates a large volume of waste which is often discarded into environment without being properly treatment. These effluents are formed by organic molecules and are characterized by been colored that alter the properties of water turning it improper for consumption. To treat these effluents, it can be advantageous to use heterogeneous catalytic processes of low cost. Clays have been widely studied as catalyst supports because of their abundance in the Earth's crust and its low cost. In this work vermiculite and bentonite clays have been used as a support for the catalyst of niobium oxyhydroxide and by the deposition-precipitation method it was obtained composites formed from these materials. The composites were characterized and the main techniques showed a change in both clays. The results X-ray diffractometry (XRD) showed that there was a decrease in reflection intensity and a shift of the main peak of both clays when oxyhydroxide niobium is added to the structure. The infrared spectroscopic analysis shows adsorption bands in both composites materials which indicate that the composite was actually formed and scanning electron microscopy images also confirmed this change. It was done oxidation and photocatalytic oxidation tests with the composites and photocatalytic oxidation test showed the best results. In this test vermiculite composite (Nb/V0) showed a higher photocatalytic activity by removing 98% of the color of the orange methyl dye in 90 minutes of reaction while the composite material of bentonite (Nb/B0) removed only 63% during the same time reaction. This activity is due to the composite Nb/V0 have presented a lower value band gap (3,08eV) that the composite Nb/B0 (3,33eV).