Arthrobacter sp. as a toxic metal biosorbing material: Ionic characterisation of the biomass and its use entrapped in a poly-HEMA matrix

摘要

A study of metal (copper, nickel and lead) sorption abilities of the Arthrobacter sp. bacterium has been reported in this work. Arthrobacter sp. was firstly potentiometrically titrated in order to have a rough characterisation of functional groups on the cell wall. Carboxylic and aminic groups were evidenced by the titration curve. Active groups for biosorption were observed on the cell wall by performing sorption experiments, using lisozime treated biomass. Arthrobacter sp. was tested in a free condition (i.e. suspended in solution) and in an immobilised condition, trapped in a polymeric martix of poly-hydroxoethylmethacrylate. The equilibrium of the process was in all cases well described by the Langmuir isotherm. The highest values experimentally observed for the metal specific uptake were 46 mg Cu/g, 13 mg Ni/g and 130 mg Pb/g. The Shrinking Core Model was used for the fitting of experimental data obtained with immobilised biomass. The effective diffusivity of copper inside the polymeric matrix was estimated at about 3 10~(-6) cm~2 s~(-1).