Effect of the Catalyst Support on Dye Degradation Using Advanced Oxidation Processes Treatment: Application of the Fractional Factorial Design

摘要

The present study aims to assess the capacity of natural acidified clay (Ht) and commercial clay (K10) to be used as catalyst supports for the degradation of an azo dye, i.e., Congo Red (CR), using three types of advanced oxidation processes (AOPs), namely the heterogeneous Fenton process, the photocatalysis process, and the photo-Fenton process. The two supports were intercalated with iron species using different loadings. The reaction efficiency for each step of the synthesis was confirmed using the nitrogen gas adsorption-desorption method for measuring the surface area and pore volume, as well as the X-ray powder diffraction (XRD) technique. In addition, the X-ray fluorescence (XRF) measurements were used to determine the chemical compositions of both clays (Ht and K10). The results obtained from the catalytic tests indicated that both catalysts, i.e., 5FePL-K10 and 10FePL-Ht, showed the highest decolorization efficiencies, 94% and 92% respectively, when using the heterogeneous photo-Fenton process. In order to find the optimal conditions for CR degradation, using the heterogeneous photo-Fenton process for the two catalysts 5FePL-K10 and lOFePL-Ht, a fractional factorial design was established. For this, six factors, namely pH (A), CR concentration (B), H_2O_2 volume (C), catalysts weight (D), time (E), and catalyst support (F), were chosen for the purpose of constructing a two-level fractional factorial design and noted 2~(6-1). The correlation factor between the experimental and predicted values by the polynomial expression for the CR degradation was greater than 93%.