Preparation and characterization of mesoporous γ-Al2O3 recovered from aluminum cans waste and its use in the dehydration of methanol to dimethyl ether

The present study includes synthesis of two γ-Al2O3 samples from waste aluminum cans using a simple precipitation method. Precipitation was carried out using two different precipitating agents (i.e. NaOH and NH4OH). The two prepared alumina samples were characterized by means of X-ray diffraction (XRD) and N2 adsorption–desorption techniques. Surface acidity of γ-Al2O3 samples was measured by adsorption of two different probe molecules (i.e. pyridine and dimethyl pyridine) followed by desorption measurements using thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Catalytic activity of the two prepared alumina samples towards the dehydration of methanol (to dimethyl ether) was studied in a fixed bed reactor at 300 °C. For comparison reasons, commercial γ-Al2O3 sample was, also, tested for the same catalytic reaction under the same conditions. Results showed that the alumina sample prepared using NaOH as a precipitating agent exhibited a better catalytic activity and stability compared with that prepared using NH4OH and showed a similar activity as the commercial γ-Al2O3 sample.