Application of chemometric methods to resolve intermediates formed during photo- catalytic degradation of methyl orange and textile wastewater from Ethiopia

Abstract

The efficiency of two catalysts (TiO₂ and TiO₂ supported on zeolite) for the photocatalytic degradation of methyl orange dye and wastewaters from Ethiopian textile industry was evaluated by chemometric methods from UV/Vis data of the reaction mixtures at different times. Multivariate curve resolution statistical analysis combined with an alternating least squares algorithm (MCR-ALS) proved to be an efficient method to resolve the different intermediates present during the photocatalytic degradation of the pollutants and to provide information about their evolution with time. Methyl orange photodegradation at pH = 3 showed different intermediate and concentration profiles than at pH = 6. The evolution of intermediates from textile wastewater photodegradation could also be resolved by this method. From the concentration profile or the reactants, a kinetic study was done. Results revealed that all the photodegradation reactions followed a first order kinetics. When TiO₂ supported in Zeolite is used, reactions are in general slower, probably due to a mechanism of adsorption/desorption.

KEY WORDS: Chemometrics, Dye photodegradation, Wastewater, MCR-ALS, Methyl Orange

Bull. Chem. Soc. Ethiop. 2017, 31(2), 223-232.

DOI: http://dx.doi.org/10.4314/bcse.v31i2.4