Abstract
Mesoporous nanocomposite membranes with vanadium oxide-carbon nanotubes (VxOy-CNTs) embedded in gamma-Al2O3 were successfully synthesized using the dip coating method. The membranes were evaluated for styrene oxidation to determine the optimum styrene conversion and benzaldehyde selectivity. Several factors that influence the preparation of defect-free coatings, such as the type of binder, the binder addition time and surface support treatments, were investigated. The physico-chemical permeation properties of the membranes were characterized using scanning electron microscope, transmission electron microscope (TEM), X-ray Diffraction XRD, Nitrogen adsorption (BET) and Thermogravimetric TGA. Response surface methodology (RSM) was used to investigate the effects of oxidant (H2O2) concentration, temperature, contact time and catalyst loading on styrene conversion and the selectivity of benzaldehyde. Based on the RSM analysis, the optimal oxidation conditions included a reaction temperature of 45 A degrees C, a differential pressure of 1.5 bars, a molar ratio of H2O2: styrene of 1.5:1 and a catalyst loading of 30 %. These conditions resulted in the maximal styrene conversion of 25.6 and 84.9 % benzaldehyde selectivity.