985 hits

Green synthesis of gamma alumina (?-Al2O3) nanoparticles (NPs) with facetted and cubeoctahedral morphologies was undertaken from waste (beverage aluminium cans) via precipitation technique and calcination at the temperature of 1000oC. The structural properties of ?-Al2O3 were determined with a combination of techniques including BET surface area, field emission scanning electron microscopy (FESEM) with energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM) and x-ray powder diffraction (XRD). XRD analysis confirmed the formation of ?-Al2O3 NPs by comparing with the standard of ?-Al2O3 structure. The BET surface area measured was 129 m2/g. High-resolution transmission electron microscopy (HRTEM) analysis provided evidence of surface-enhanced contrast in facetted ?-Al2O3 NPs structures similar to the commercial ?-Al2O3 NPs. ? Malaysian Journal of Microscopy (2021). All rights reserved...

468 hits

The inferior activity of ?-Al2O3 (GAL1) from the waste aluminium for CO2 methanation was improved using Ba promoter. Ba promoted CO2 conversion to ?82% with 100% methane selectivity at 400 C (Ni-Ba/GAL1), compared to ?10% conversion without Ba (Ni/GAL1). Acid digestion of waste aluminium formed residual Al2(SO4)3 at ?0.5% atomic weight, forming the detrimental NiAl2O4 under reaction conditions. Ba inhibited NiAl2O4 formation by producing BaAl2O4, increasing Ni-Ba/?-Al2O3 stability for 50 h at 400 C. In-situ DRIFTS analysis revealed that NiAl2O4 caused CO2 methanation via CO2 dissociation into CO, followed by high temperature hydrogenation to CH4. Ba promotes catalytic activity and stability of alumina with sulfur impurities by maintaining Nio oxidation states to catalyze CO2 hydrogenation to formate at low temperatures, producing a high methane yield. In addition to transforming waste aluminium into a valuable material, investigation on ?-Al2O3 catalytic activity expands its potential .....

106 hits