Ni2+adsorption performance of immobilized Saccharomyces cerevisiae in fractionated clay from Southeast Sulawesi

Abstract

This research shows the optimum adsorption conditions of three adsorbents, i.e clay, S. cerevisiae biomass, and S. cerevisiae biomass immobilized on clay. Fractionated clay were obtained by reacting clay with KMnO₄, H₂SO₄, and HCl. S. cerevisiae biomass was obtained by heating S. cerevisiae biomass from pure isolates. Immobilization of S. cerevisiae biomass in clay was carried out by mixing both in a ratio of 25:5 and 50:5 (mL biomass: g clay). The results of adsorbent characterization by FTIR showed that the functional groups in immobilized S. cerevisiae biomass with a ratio of 50:5 (mL biomass: g clay) were Si-OH, Si-O-Si, N-H, O-H, and C-H. Adsorption of Ni²⁺ ions in each adsorbent was carried out by the batch method using the parameters of concentration and contact time. The concentration of the remaining Ni²⁺ ions was analyzed using AAS. The capability of adsorption of Ni²⁺ ions in each adsorbent, optimum at a concentration of 50 mg/L with a contact time of 120 minutes. Whereas the optimum adsorption capacity of Ni²⁺ ions by clay, S. cerevisiae biomass, and immobilized S. cerevisiae biomass, were respectively 0.0013 mg/g, 0.0139 mg/mL and 0.0005 mg/g, while the adsorption energies were 16.684, 10.735 and 19.084 kJ/mol, respectively.