Removal of Cadmium from Aqueous Solutions by Saccharomyces cerevisiae–Alginate System

The aim of this study was to determine the Cd(2+) removal capacity of a biosorbent system formed by Saccharomyces cerevisiae in calcium alginate beads. The adsorption of Cd(2+) by a S. cerevisiae–alginate system was tested either by batch or fixed-bed column experiments. The S. cerevisiae–alginate system was characterized using dynamic light scattering (DLS, zeta potential), size, hardness, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy. Beads of the S. cerevisiae–alginate system showed a spherical–elliptical morphology, diameter of 1.62 ± 0.02 mm, 96% moisture, negative surface charge (−29.3 ± 2.57 mV), and texture stability during storage at 4 °C for 20 days. In batch conditions, the system adsorbed 4.3 µg of Cd(2+)/g of yeast–alginate beads, using a Cd(2+) initial concentration of 5 mg/L. Adsorption capacity increased to 15.4 µg/g in a fixed-bed column system, removing 83% of total Cd(2+). In conclusion, the yeast–alginate system is an efficient option for the removal of cadmium at low concentrations in drinking water.