Aplicação de beads de líquido iônico na remoção de cobalto de efluentes industriais

Abstract

Heavy metal pollution of aquatic ecosystems by industrial effluents is a recurring problem. These residues affect water quality, and their toxic effects harm humans, even causing death in some cases. To avoid these effects on aquatic systems, it is crucial to treat or remove these substances before they reach the environment. Strict legislation and increasing concerns are driving the search for new sustainable technologies for treating effluents containing these contaminants. These residues can have varying characteristics depending on the industry type and can be corrosive or pathogenic. Therefore, each must receive specific treatment before returning to the environment. Ionic liquids, solvents classified as green, have high adsorbent properties and have been studied for this purpose because of their ability to dissolve polar and nonpolar substances. When applied in pre-treatment or alone with adsorption elements, they can remove heavy metals from effluents. Owing to their thermal and chemical stability, low volatility, and reduced toxicity, they are promising environmental solutions for these pollutants. The efficiency of alginate beads containing an ionic liquid derived from the imidazolium cation for removing cobalt ions from standard solutions was evaluated. The beads were produced by controlled dripping, resulting in uniform spheres with low residual moisture content after drying. To determine the residual concentrations, a calibration curve with a coefficient of determination of 0.9996 was developed, indicating high analytical reliability of the method. Adsorption tests were conducted and demonstrated a sharp decrease in concentration to 0.0576 g·L⁻¹ with 0.25 g of beads, while similar values were obtained for 0.50 and 1.00 g of beads. The results obtained reinforce the viability of materials containing ionic liquids as efficient alternatives for adsorption processes.