Synthesis, characterization, and application of Saccharomyces cerevisiae/alginate composites beads for adsorption of heavy metals

Abstract

• Beads of residual biomass of S. cerevisiae /alginate composite was developed and applied to adsorption of toxic metals. • Biosorbent was characterized by pHpzc, DRX, FTIR, SEM and TGA. • Biosorption isotherms is of high affinity, with adsorption capacity of 179.1, 72.1 and 30.7 mg g −1 for the Pb (II), Cr (VI) and Cd (II). • More than 95 % removal of the Cr (VI) present in the real wastewater was raised with adsorbent dosages higher than 3.0 g L −1 . • Biosorbent composite produced proved to be promising for the removal of the studied heavy metals. The biomass of Saccharomyces cerevisiae is a by-product widely generated by the beer producing industries and promising for use as a biosorbent; however, its use in natura becomes impracticable due to the fragmentation in aqueous solutions. In this way, the encapsulation process can overcome these barriers, improving its mechanical properties. This study aimed to develop beads from the biomass of residual Saccharomyces cerevisiae from brewing using alginate base and to evaluate the adsorbent potential of toxic metals Pb (II), Cr (VI) and Cd (II) in water. The adsorbent material was prepared and characterized. The adsorption pH was determined, and the adsorption equilibrium were analyzed using isothermal models. Adsorption tests involving real wastewater were also conducted. The removal affinity occurred in the following order Pb (II) > Cr (VI) > Cd (II), with maximum monolayer removal capabilities estimated by the Langmuir model of 179.1, 72.1 and 30.7 mg g −1 , respectively. The application in real wastewater provided removal superior to 95 % of Cr (VI) using doses of biosorbent from 3.0 g L −1 . In general, the biosorbent composite produced proved to be promising for the removal of the studied heavy metals.