walnut shell-assisted synthesis of mesoporous alumina

in the present study high surface area amorphous boehmite and γ-alumina were synthesized using walnut shell as template. this green, simple and useful synthetic protocol was based on the precipitation of aluminum hydroxide as the source of aluminum on biomass in an aqueous phase followed by calcination. the influence of walnut shell was evaluated by varying the calcination atmosphere. materials were characterized using x-ray diffraction, fourier transform infrared spectroscopy, energy-dispersive x-ray spectroscopy, scanning electron microscopy and n₂ adsorption/desorption porosimetry and the results exhibited high surface area for boehmite and γ-alumina. furthermore, the pore size and surface area of these mesoporous materials can be adjusted by varying the experimental conditions. additionally, boehmite was studied as the support of vanadium catalyst for the oxidation of alcohols by hydrogen peroxide. we have found that resulting v-loaded material act as an effective catalytic system for the oxidation of a wide range of alcohols in 1,4-dioxane. the catalyst can be recovered and reused four times without loss of activity.