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 quanti®ed 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 coef®cients are reported for some different system conditions. Both materials are determined to be effective adsorbents and could ®nd application in the treatment of contaminated wastestreams.

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This is an author's version published in: http://oatao.univ-toulouse.fr/20826

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The potential of technical hydrolysis lignin (THL), a low-cost and abundantly available material, to act as an adsorbent of 2-nitrophenol (2-NP) has been investigated. The extent of mononitrophenol uptake was determined conducting parallel single-component kinetic experiments in standardized batch adsorbers. The effect of the operating parameters, initial sorbate concentration, and mass of adsorbent was tested. The applicability of three kinetic/mass transfer models was estimated on the basis of comparative analysis of the corresponding rate parameters (k 1, k 2, k i), equilibrium capacity ( , ), and correlation coefficients ( , , ). Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. The Langmuir and Freundlich isotherm models were applied to describe the experimental results. The Langmuir model was found to best represent the equilibrium data for 2-NP uptake on THL. The sorption characteristics and the calculated sorption capacity of the lignin proved the feasibility of its use as a potential and alternative sorbent for 2-NP removal.

The adsorption of para-chlorophenol onto an active carbon made from waste apricot stones has been studied. The batch kinetic adsorption processes have been measured for a range of system variables including agitation rate, initial concentration of para-chlorophenol, mass of carbon and particle size of carbon. The extent of adsorption is reported as plots of solid phase concentration against the square root of time. An intraparticle diffusion parameter is used to describe the mass transfer within the adsorbent. This parameter varies with the square root of time and can be related to the type of structure which occurs within an activated carbon. A correlation is proposed relating the process variable with the intraparticle diffusion parameter in each of the three mass transfer regions.

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