Removal of metal ions using an industrial biomass with reference to environmental control

The utility of a waste, dead fungal biomass in the removal of various metal ions such as calcium, iron, nickel and chromium when present individually and in possible combinations has been demonstrated. Although the tests were carried out using synthetic solutions of varying pH and metal ion concentrations, the results are representative of typical waste effluents emanating from leather, paper, paint and mineral processing industries as well as electroplating circuits. The maximum metal uptake was found to be dependent on solution pH (4-5 for Fe, 4-7 for Ca, 6-7 for Ni and 6 for Cr) and increased with biomass loading up to 10 g/l. The adsorption densities for various metal ions could be arranged as Ca > Cr(III) > Ni > Fe > Cr(VI). The presence of co-ions in binary, ternary and quarternary combinations decreased the metal uptake; the Ni uptake being most significantly affected while that of Cr(VI) the least. Possible mechanisms of metal ions removal are outlined along with a flow sheet for potential industrial application. (C) 1998 Elsevier Science B.V.