Application of lechuguilla (Agave lechuguilla torr.) extracts for copper (II) removal from water models by spherical agglomeration

Copper in water is an essential micronutrient for human beings, it can produce damage effects for health due to excess. Toxicity of this element is attributed to its divalent Cu (II) species in natural aquatic environments. For copper removal in water, the spherical agglomeration technique can be applied by using industrial tensoactive agents with high Sodium (Na) contents. In this study, a Cu (II) removal method was developed using extracts of pulp of lechuguilla (Agave lechuguilla Torr.), which is a waste in many industries in Mexico, rich in saponines and free of Sodium. The technique of spherical agglomeration was carried out in synthetic water (2 to 15 ppm) using extracts of pulp of lechuguilla as biosurfactant. The experimental conditions were: 0.1-2.0 g-extract/g metal, T°=22°C, pH_Initial=8.0, and constant stirring at 600 rpm. Saponines were measured by HPLC-DAD in the extract, comparing the retention time of typical peaks with a standard. Residual Copper and Sodium were measured by atomic absorption spectroscopy. A mean 98.7% Copper removal efficiency was reached in all assays, which meets the requirements of the tap-and waste-water regulations. According to this study, we suggest to replace the industrial tensoactive agents bylechuguilla (A. lechuguilla) extracts in order to remove Cu (II) from water by spherical agglomeration technique.