Removal of hexavalent chromium ions by Yarrowia lipolytica cells modified with phyto-inspired Fe~0/Fe_3O_4 nanoparticles

摘要

The removal of hexavalent chromium [Cr (Ⅵ)], an important ground water pollutant by phyto-inspired Fe~0/Fe_3O_4 nanocomposite-modified cells of Yarrowia lipolytica (NCIM 3589 and NCIM 3590), was investigated. Electron microscopy and magnetometer studies indicated an effective modification of yeast cell surfaces by the nanocomposites. The effect of pH, temperature, agitation speed, contact time and initial metal ion concentration on the removal of Cr (Ⅵ) was determined. The specific uptake values at pH 2.0 were 186.32 ±3.17 and 137.31 ±4.53 mg g~(-1) for NCIM 3589 and NCIM 3590, respectively, when 1000 mg L~(-1) of metal ion concentrations were used. The equilibrium data fitted to Scatchard, Langmuir and linearized Freundlich models suggesting that adsorption played a role in the removal of Cr (Ⅵ) ions. The surface modified yeast cells displayed higher values of Langmuir and Scatchard coefficients than the unmodified cells indicating that the former were more efficient in Cr (Ⅵ) removal. The enhanced detoxification of Cr (Ⅵ) ions by this composite material could be attributed to the reductive power of the Fe~0/Fe_3O_4 nanocomposites as well the yeast cell surface functional groups.