Influence of composition and size distribution of Al₂O₃/Fe₂O₃ microspheres, produced by internal gelation, on the adsorption of heavy metals

ABSTRACT

Heavy metals are widely used in several industrial sectors, such as metallurgy, mining, electroplating, textiles, fertilizers, batteries, pesticides, printed circuit boards, among others, and are commonly found in the effluent generated by these industries. As they are extremely toxic and may contaminate both the ecosystem and the surrounding community, an efficient effluent treatment is necessary in order to reduce the concentration of these elements to acceptable levels before disposal. Among the various possible effluent treatments, adsorption is widely used for its simplicity, efficiency, and low cost. In this work, were produced, by internal gelation method, porous microspheres containing alumina and hematite in different concentrations, which were used as adsorbents in adsorption assays, in batch and fixed bed column, of aqueous solutions containing Zn²⁺, Ni²⁺ e Mn²⁺. The microspheres were characterized regarding morphology and particle size distribution, specific surface area, gas adsorption and crystalline phases. It was possible to evaluate the effect of the composition and size distribution of the microspheres on the adsorption of heavy metals. It was obtained more than 90% of adsorption of heavy metals, in the fixed bed column regime, indicating high efficiency of these microspheres as adsorbents of these ions.

Keywords
Adsorption; Heavy metals; Alumina/hematite microspheres; Internal gelation; Materials technology