BIOSORPTION OF TERNARY CADMIUM, NICKEL AND COBALT IONS FROM AQUEOUS SOLUTION ONTO <i>SACCHAROMYCES CEREVISIAE</i> CELLS: BATCH AND COLUMN STUDIES

Abstract

The aim of this study was to remove cadmium, nickel and cobalt ions from aqueous solutions using yeast, Saccharomyces cerevisiae, pre-treated with ethanol. The cells are immobilized using polysulfone in both batch and continuous systems. To optimize the adsorption capacity of the yeast biomass, a batch system was used to investigate the effects of initial pH, initial biomass dose and initial metal ion concentration. Optimum conditions were obtained at pH 8 with a biomass of and ion concentrations of 8 and 100 mg L −1 , respectively. Under these conditions, the maximum uptake capacity was 3.1 mg g −1 for cadmium, 1.2 mg g −1 for nickel and 0.68 mg g −1 for cobalt. To estimate the biomass uptake capacity of the ethanol pretreated S. cerevisiae, the isothermal Langmuir model was found to be a better fit with a correlation coefficient of R 2 <0.964. Factors observed affecting biomass ion adsorption in the continuous system are initial concentration of single or multi-metallic ions, the column height of bead system and the input flow rate. The optimum conditions for the continuous system were determined at pH 8, initial metal ion concentration of 100 mg L . The calculated uptake capacity of the metal ions was 3.74 mg g −1 for cadmium, 1.57 mg g −1 for nickel and 1.56 mg g −1 for cobalt. The Thomas model (0.9524<R 2 <0.9957) was shown to be more consistent compared with the test results. Polysulfone immobilization of yeast was found to increase removal by 48% compared to non-immobilized ethanol pr-treated yeast.

EFFECTS ON THE MINERAL COMPOSITION OF FLEISCHMANN’S YEAST (Saccharomyces cerevisiae) FERMENTING SUGAR-CANE JUICE CONTAMINATED WITH COBALT

“…The intracellular content of K tended to decrease with the increase of Co contents in the growth medium in all tested pH levels ( Table 2). It is also likely that pH influences this tendency, considering that the decrease in pH levels goes along with the decrease in the intracellular content of K. These results are in accordance with those reported by several authors (BRADY; DUNCAN, 1994;ASSMANN et al, 1996;GALEDAR;YOUNESI, 2013). Heavy metals may cause the fluidization of the yeast-cell membrane, inducing K channels to open and intracellular K levels to decrease (ASSMANN et al, 1996;MARIANO-DA-SILVA et al, 2007).…”

“…In higher levels of pH, Co oxides and hydroxides are formed with decreasing quantities of free and available ions for the interaction with the yeast decreasing then the absorption and toxic signs (GALEDAR;YOUNESI, 2013). Roughly speaking, the intracellular rates of Co increased with metal increment in the growth medium.…”

“…The absorption of cobalt (Co) by yeast cells depends on 1) the amount of glucose, 2) the initial pH level 3) the concentration of Co in the juice and 4) the metabolism of the yeast cells, considering that, dead cells are not capable of accumulating Co, releasing it to the media when killed (HELDWEIN et al, 1977;GALEDAR;YOUNESI, 2013;SAAD, 2015). After the absorption, the Co +2 ions are transported through the membrane cell, probably by membrane transport proteins, until the cytosol, where they are bonded to metalloproteins in the vacuole (HELDWEIN et al, 1977).…”

Cadmium removal from aqueous solutions via biosorption onto acclimatized activated sludge

“…Living and non-living biological biomasses such as bacteria, algae, yeast, or seaweed, have been efficiently employed in many studies (Pandiyan and Mahendra 2012;Singh and Singh 2012;Paraszkiewicz et al 2009;Galedar and Younesi 2013;Solisio et al 2008;Rangsayatorn et al 2004;Cruz et al 2004;Lodeiro et al 2005;Wang et al 2006;Hawari and Mulligan 2006;Khosravan and Lashkari 2011). Effect of different strains as well as other adsorption parameters has also been tested and a good potential in uptake of cadmium ions from aqueous solutions has been verified.…”

Adsorption of Nickel and Zinc by Residual Soils

“…Where: Co and Cf = Initial concentration and equilibrium concentration of metal solution respectively (mg/L) V = Volume of solution added (mL) W = Mass of air-dried soil (g) Langmuir isotherm model is valid for mono-layer adsorption onto a surface with a finite number of identical sites and also considered several assumptions like the localized adsorption, similar energies on the surface of active sites where there is no interaction between adsorbed molecules and the surface of heterogeneous catalytic reactions (Parida et al, 2012;Tang et al, 2012). Langmuir models represented in following equations (Galedar and Younesi, 2013) Equation 2:…”