Biosorption of Copper by Immobilized Biomass of Pseudomonas stutzeri

The kinetics of copper ion biosorption by Pseudomonas stutzeri cells immobilized in alginate was investigated. During the first few minutes of the metal uptake, the copper biosorption was rapid and then became progressively slower until an equilibium was rapid, and then became progressively slower until an equilibrium was reached. At a biomass concentration of 100g/l, the copper biosorption reaction reached approximately 90% of the equilibrium position within 30 min. A Freundich-type adsorption isotherm model was constructed based on kinetics with different amounts of biomass. When using this model, the experimental values only agreed well with the predicted values in a solution containing less than 200 mg/l Cu(II). Desorption of the bound copper ions was achieved using electrolytic solutions of HCl, $H_2SO_4$, EDTA, and NTA (0.1 or 0.5 M). Metal desorption with 0.1 M NTA allowed the reuse of the biosorbent for at least ten consecutive biosorption/desorption cycles, without an apparent decrease in its metal biosorption capability. A packed-bed column reactor of the immobilized biomass removed approximately 95% of the metal in the first 30 liter of wastewater [containing 100 mg/l Cu(II)] delivered at a rate of 20 L/day, and, thereafter, the rate gradually decreased.