Fe-MKSF catalyst for oxidative degradation of methyl orange: influence of iron/clay ratio

Abstract

Heterogeneous Fenton-like reaction has received considerable research attention as one of promising treatment methods in degrading recalcitrant organic pollutant. In recent years, iron immobilized-montmorillonite KSF (Fe-MKSF) catalyst displayed decent catalytic activity in degrading organic contaminants. Inspired by such performances, further understanding on the detailed structural properties as well as its’ catalytic activity were performed to gain further insights towards the influence of iron to clay ratio during the catalyst synthesis. Fe-MKSF catalysts were synthesized by impregnation-hydrothermal method at varies iron molarity to the clay ratio. A series of Fe-MKSF catalyst ranging between 10 until 50 molarity of iron/clay ratio as well as pristine MKSF and iron oxide were characterized using nitrogen sorption and XRD analysis. The catalytic performance of resultantFe-MKSF catalysts were tested for the oxidative degradation of methyl orange (MO) in heterogeneous Fenton-like reaction. At pH 3, 0.2 g/L Fe-MKSF, 12 mM of hydrogen peroxide and 25 mg/L MO’s initial concentration; Fe-MKSF-20 exhibited with exceptional performance of 85% removal. Such behavior was attributed to the high surface area (SBET=105.76 m2/g) and pore volume (0.39 cm3/g) of Fe-MKSF-20 compared with others iron/clay ratio. Moreover, form the XRD analysis, it was found that the immobilized iron on the MKSF was in hematite phase for all Fe-MKSF catalysts. In conclusion, the iron/clay ratio plays vital role in modulating the structural properties, which directly corresponded to the resultant catalytic activity of Fe-MKSF