engleski

Statistical evaluation of UV/TiO2/H2O2 and Fe2+/H2O2 process for the treatment of coloured wastewater : a comparative study

In this work two types of advanced oxidation processes ; photocatalytic oxidation, UV/TiO2/H2O2 and classic Fenton oxidation, Fe2+/H2O2, have been applied for the treatment of a model wastewater containing reactive azo dyes, C.I. Reactive Violet 2 (RV2) and C.I. Reactive Yellow 3 (RY3). In order to evaluate the effect of the initial concentration of catalysts, mass.conc.(TiO2) or [Fe2+], initial concentration of oxidant, [H2O2] or the initial oxidant/catalyst molar ratio [H2O2]/[Fe2+] and pH on apparent mineralization and decolourization rates, a response surface method (RSM) D-optimal design was used. Mineralization was described by pseudo-first-order kinetics with the highest observed rate constants ; km, UV = 0.0065 min-1 in the case of UV/TiO2/H2O2 process and km, F = 0.0213 min-1 in the case of Fenton process. A kinetic model describing decolourization on wavelengths of maximum absorbance for studied dyes, lambdamaxRV2 550 nm, and lambdamaxRY3 385 nm, was composed of two first-order in-series reactions with corresponding decolourization rates. The effects of each factor on the efficiency of the applied processes were found to be significant.

wastewater treatment; reactive azo dyes; photocatalytic oxidation; Fenton oxidation; pesponse surface method (RSM); D-optimal design

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