Experimental design for optimization of the photocatalytic degradation process of the remazol red dye by the TiO2/expanded perlite composite

In this study, the photocatalytic decolorization of remazol red dye (RR) was evaluated using TiO2 based composites supported on the expanded perlite (T-EP-10% and T-EP-30%). The characterization techniques used in this work were IR, XRD, XRF and particle size analysis. In order to optimize the RR discolouration process, a factorial planning was applied. The best experimental conditions are the RR initial concentration of 10?mg L-?1, composite T-EP-30% and both PHs showed positive results in the decolorization. The tests performed at pH 2.0 showed 100% removal of RR colour in 180?min and at pH 5.0 100% colour removal was obtained in 120?min. The decolorization process follows a pseudo first-order-kinetics, the k(app) of 0.01191?min(?1) for the tests at pH 5.0 and 0.00812?min(?1) for the tests at pH 2.0. The results of energy cost shown that in both pH 2.0 and 5.0 tests were feasible in efficiency and economically. The energy consumption for the test at pH 2.0 was 0.297?kWhdm(3) and final cost of R$ 0.163, while the energy consumption for the test at pH 5.0 was 0.198?kWhdm(3) and a final cost of R$ 0.111.