Optimal Decolorization Efficiency of Reactive Red 3 by Fe-RH-MCM-41 Catalytic Wet Oxidation Coupled with Box-Behnken Design

Abstract

The reactive red 3 was degraded by catalytic wet oxidation process over Fe-RH-MCM-41 prepared by Direct Hydrothermal Technique (DHT) at Si/Fe molar ratio of 10 using silica from rice husk. The extended reaction conditions were studied as a function of reaction temperatures, initial H2O2 concentrations and initial pH of solutions designed by Box-Behnken design (BBD) based on Response Surface Methodology (RSM) to achieve the optimal condition and interaction of independent variables. The characterizations of catalyst were studied by XRD, BET surface area and TEM to explain the morphology of surface and to confirm the hexagonal structure. The results showed the 2theta peak can be indexed to hexagonal lattice that also confirmed by TEM result and surface area about 650 m2/g. All of independent variables showed significant on the degradation of reactive red 3 except for initial H2O2 concentration.

Degradation of Reactive Red 3 by heterogeneous Fenton-like process over iron-containing RH-MCM-41 assisted by UV irradiation

“…However, it was observed that high concentration of Fe leached in the solution. To solve Fe leaching, substitution in the lattice of mesoporous materials was studied in this research similar to our previous work [16]. Yaman and co-worker [11] studied Fenton-like process by using iron-containing ZSM-5 zeolites to degrade CI Reactive Red 141 dye and also reported that the leached Fe was low (lower than 2 mg/l).…”

“…The independent variables and levels of variables are shown in Table 1. The main differences of independent variables in this research as compared to our previous work [16] were ranges of pH of solutions and initial H 2 O 2 concentrations. The solution pH were changed from 3, 6, and 9 to 3, 4, and 5 and the initial H 2 O 2 concentrations were changed from 24.475, 48.950, and 73.425 mM to 48.375, 64.500, and 80.625 mM.…”

“…The structure of the RR3 is shown in Fig. 1 [16]. RR3 solution was prepared by dissolving it with distilled water.…”

“…The Fe-RH-MCM-41 was prepared according to our previous work [16,17] (i) Hexadecyltrimethyl ammonium bromide (CTAB) of 4.50 g and Fe precursor were mixed with 90 ml of deionized water in a Teflon beaker, (ii) sodium silicate was prepared in another Teflon container by dissolving 5.00 g of NaOH in 30 ml of deionized water, then, 3.00 g of rice husk silica was added as obtained from Si/Fe mole ratio of 10. Next, the solution was stirred vigorously until it was clear and viscous.…”

“…The independent variables such as initial H 2 O 2 concentration, pH of solution and reaction temperature were studied in terms of main, square, and interaction effects using Box-Behnken design (BBD) based on Response Surface Methodology (RSM). Compared to our previous work, different range of values was given to the said variables [16] to find the optimum condition.…”