Investigation of zinc(II) adsorption on Cladophora crispata in a two-staged reactor

In this study, the adsorption of zinc(II) ions on Cladophora crispata, a gr een alga, was studied with respect to initial pH, temperature, initial meta l ion and biomass concentration in order to determine the optimum adsorptio n conditions. Optimum initial pH values for zinc(II) ions were found to be 5.0 at optimum temperature, 25 degrees C. The initial adsorption rates incr eased with increasing initial zinc(II) ion concentration up to 100 mgdm(-3) . The Freundlich and Langmuir adsorption isotherms were developed at variou s initial pH and temperature values. Then, the adsorption of zinc (II) ions to C crispata was investigated in a two-staged mixed batch reactor. The re sidual metal ion concentrations (C-eq) at equilibrium at each stage for a g iven quantity of dried algae (X-o)/volume of solution containing heavy meta l ion (V-o) ratio were calculated by using Freundlich and Langmuir isotherm constants, it was observed that the experimental biosorption equilibrium d ata for zinc(II) ions are in good agreement with those calculated using bot h Freundlich and Langmuir models. The adsorbed zinc(II) ion concentration i ncreased with increasing X-o/V-o ratios while the adsorbed metal quantities per unit mass of dried algae decreased. (C) 2000 Society of Chemical Indus try.