In this chapter the adsorption fundamentals using biomass as adsorbents in the removal of metallic ions are presented. The research as shows the importance of many factors that affects the adsorption, such as the biomass superficial area, system temperature, pH, initial concentration of the metal, biomass amount and status (living or dead). The study was directed at the approach of two applications using Saccharomyces cerevisiae yeast in the adsorption of Cd2+ metal ions. In the first application it is discussed the influence of the pH of the medium and the biomass status (living or dead) in the adsorption of Cd2+, in batch. In the second application, it was studied the adsorption of Cd2+metallic ions through the Saccharomyces cerevisiae yeast immobilized in chitosan, in fixed bed, where the influence inlet mass flow rate and the initial effluent concentration on the adsorption capacity and percentage of Cd2+ ions removal are evaluated.The studies realized are supported by statistical analysis with 95% confidence intervals.