Removal of copper ions from alembic using agro-industrial residues as biosorbents.

is a typical Brazilian distilled beverage made from fermented sugarcane juice. The copper levels in alembic are of great concern among producers, and the removal of this contaminant is important for the quality of the product. The present study aimed to remove copper ions from alembic by adsorption. Sugarcane bagasse, okara, Lam., three different types of zeolites, and two types of commercial charcoal were tested as biosorbents. The heat-treated sugarcane bagasse removed 100% of the copper present in a cachaça sample, while other low-cost natural adsorbents had close to 50% removal as was observed for seeds and okara. All adsorbents had porous and fibrous structures, favorable to adsorption. A kinetic study showed that a pseudo-second-order model was appropriate, with equilibrium times of 15 h for heat-treated sugarcane bagasse, okara, and seeds used as adsorbents. The Langmuir model better fitted the experimental data, indicating monolayer adsorption. The maximum adsorption capacity was 17.00, 0.77, and 5.33 mg of Cu g for the heat-treated sugarcane bagasse, seeds, and okara, respectively. The results presented here are promising indicating three agro-industrial residues were favorable to the adsorption of copper ions from alembic .