No abstract

Many countries around the world are facing issues in managing solid waste materials; most of these wastes such as aluminium can are deposited to the landfills, leading to environmental pollution. Recycling is considered as an effective technique to manage the aluminium can waste since it can provide benefits in terms of energy savings, reduce volumes of waste and cost-effectiveness. In this article, it was desired to turn the aluminium can waste into α-Alumina using sol-gel method. Alumina exists in many crystalline structures which degenerate to the most stable hexagonal α-phase at high temperatures. α-Alumina (a-Al2O3) is the most stable crystalline structure widely used and studied as electronic packaging, corrosion resistance ceramics, high-temperature structural material, and translucent ceramics. FTIR, XRD, SEM-EDX, TGA, and BET were employed to investigate the properties of a-alumina. The experimental results obtained from this study demonstrates the possibility of producing alumina from an aluminium can waste with the exact surface area of 5.2105 m2/g, crystallite size at 132.50 nm and total weight loss of 2.71% at 900 °C calcination temperature.

Aluminum waste-can management in Malaysia has recently become a serious environmental and public health issue, particularly in metropolitan areas. This has prompted the need to valorize these waste-cans into value-added products using the most economical and environmentally friendly techniques. In this study, the sol–gel technique was used to synthesize high-quality alumina from the aluminum waste-cans collected. From this method, the observed peaks of the synthesized alumina were identified as diaspore (α-AlO(OH)), boehmite (γ-AlO(OH)), aluminum oxide, or gamma-alumina (γ-Al2O3) crystalline structure and corundum. The morphological configuration, microstructure, and functional group properties of the synthesized alumina were evaluated. All the synthesized alumina exhibited a non-spherical shape and appeared to have hexagonal-like shape particles. Moreover, the XRD patterns of the synthesized alumina AL-6-30 and AL-12-30 exhibited a small angle (1–10°) with no XRD peak, which indicated a mesoporous pore structure with no long-range order. The overall results of γ-alumina synthesized from the aluminum waste-cans showed an optimal condition in producing a highly structured γ-alumina with excellent surface-area characteristics. The synthesized alumina exhibited stronger and highly crystalline functional characteristics almost comparable with the commercially available brands on the market.

The heated aluminium containers were added to a solution of 8.0 M H2SO4 solution, which eventually yielded a solution of Al2(SO4)3 after a series of stepwise precipitation reactions. Al2(SO4)3 was presented in large quantities of H2SO4 in the white semi-fluid solution; there were some unreacted aluminium parts. The solution was subjected to filtration and then mixed with anion in a ratio of 2:3, this resulted in the formation of a white layer Al2(SO4)3•18H2O. Thereafter, Al2(SO4)3•18H2O was calcined in an electric oven for 2 h at various calcination temperatures (500, 700, 900, 1100, and 1300°C). The mixtures were heated and cooled at a rate of 10°C/min. XRD was employed to investigate variations in temperature and determination of elemental accumulation of alumina produced. Ah(SO4)3•18H2O was due to a series of aluminium compositions produced from dehydration. All transitions from low temperatures to aluminium phases were converted to high-temperature α-Al2O3. The results obtained from X-ray disintegration showed that the α-Al2O3 phase was obtained at a reaction temperature of about 1150°C and above.