Influence of Saccharomyces cerevisiae yeast cells immobilized on Cocos nucifera fibers for the adsorption of Pb(II) ions
Jarosław Chwastowski, Paweł Staroń
Abstract
The paper presents the ability of coconut fibers and its modification made with Saccharomyces cerevisiae yeast cells to remove Pb(II) ions by adsorption process. Sorbents have been characterized by the SEM-EDS, FTIR, CHN, BET analysis. Maximum Pb(II) adsorption was equal to 99.32% for Pb(II) concentration of 1000 mg/dm3 for unmodified adsorbent and 99.87% for coconut fiber containing yeast cells. The sorption capacity of unmodified material was equal to 73.627 mg/g and 63.935 mg/g for the modified one with the highest metal ion concentration (3000 mg/dm3). The lead sorption on both materials has been best described by the Langmuir isotherm what suggests that monolayer adsorption has been a type of adsorption occurring in the experiment. Additionally, pseudo-first-order, pseudo-second-order, and Weber-Morris kinetic models have been used to acquire results providing information about the nature of the adsorption process. Due to the highest fit of the R2 of the pseudo-second-order model, it can be supposed that adsorption has been a chemical reaction. Desorption studies showed that the best eluents are organic acids such as citric and acetic acids. Additionally, 5 cycles of sorption/desorption were carried out showing almost no reduction in the material removal efficiency.