Biosorption from aqueous solutions by eggshell membranes and Rhizopus oryzae:: equilibrium and kinetic studies

This study assesses the use of eggshell membranes and Rhizopus oryzae as media for the biosorption of p-chlorophenol (p-CP), 2,4-dichlorophenol (2,4-DCP), 3,5-dichlorophenol (3,5-DCP), reactive dye and cadmium from aqueous solutions. The performance of the adsorbents was quantified by measuring the equilibrium uptake and the batch rate kinetics from solutions. The constants in the Freundlich, Langmuir and Redlich-Peterson isotherm models were calculated through the linearization of the equations and linear regression. The kinetics of the adsorption systems for cadmium and a reactive dye have been assessed in a batch stirred adsorber. The effect of the process parameters such as pH, adsorbate concentration, adsorbent dosage, adsorbent particle size, temperature and agitation speed are reported. The external mass transfer coefficients are reported for some different system conditions. Both materials are determined to be effective adsorbents and could find application in the treatment of contaminated wastestrearns. (C) 2002 Society of Chemical Industry.