The ability of glutaraldehyde cross-linked chitosan beads (GCC beads) as synthetic adsorbent for adsorptive removal of Pb(II) ions from aqueous solutions is investigated in the present study. The biosorbent has been characterised by Brunner, Emmett, and Teller (BET) analysis, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. Equilibrium and column flow adsorption characteristics of Pb(II) ions on the biosorbent were studied. The effects of experimental variable parameters such as pH, concentration of metal ion, amount of adsorbent, contact time, temperature and interfering ions on adsorption have been investigated. The equilibrium data are fitted to pseudo-first order, pseudosecond order, fractionary order, chemisorption, Weber-Morris and Boyd models. Based on R 2 and error function values, it is observed that the kinetic data are better fitted to pseudo-second-order kinetic model and chemisorption model. The experimental data are analysed using Langmuir, Freundlich, and Sips adsorption isotherm models. The monolayer adsorption capacity of GCC beads as obtained from Langmuir isotherm at 35 • C is found to be 204.0 mg/g. The thermodynamic constants of the adsorption process: H 0 , S 0 and G 0 are evaluated. The results show that biosorption of Pb(II) ions on GCC beads are endothermic and spontaneous.Cetteétude examine la capacité de perles chitosanes réticulées de glutaraldéhyde (perles GCC) comme adsorbant synthétique pour l'élimination adsorptive des ions As (

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Chitosan-coated perlite (CCP) beads were prepared by dropwise addition of a liquid slurry containing chitosan and perlite to an alkaline bath. The resulting beads were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and surface area analysis. The chitosan content of the beads is 23% as determined by a pyrolysis method. Adsorption of phenolic compounds (phenol, 2-chlorophenol, and 4-chlorophenol) from aqueous solutions on chitosan-coated perlite beads was studied under batch equilibrium and column flow conditions. The binding capacity of the biosorbent was investigated as a function of initial pH, contact time, initial concentration of adsorbate, and dosage of adsorbent. Adsorption kinetic and isotherm studies, respectively, showed that the adsorption process followed a pseudo-first-order kinetic model and the Langmuir isotherm. The maximum monolayer adsorption capacity of phenol, 2-CP, and 4-CP on to the chitosan-coated perlite beads was found to be 192, 263, and 322 mg g -1 , respectively.

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A novel biosorbent was developed by the crosslinking of an anionic biopolymer, calcium alginate, with glutaraldehyde. The glutaraldehyde-crosslinked calcium alginate (GCA) was characterized by Fourier transform infrared spectroscopy and porosity and surface area analysis. The batch equilibrium and column flow adsorption characteristics of fluoride onto the biosorbent were studied. The effects of the pH, agitation time, concentration of adsorbate, and amount of adsorbent on the extent of adsorption were investigated. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherms. The data were analyzed on the basis of the Lagergren pseudo-first-order, pseudo-second-order, and Weber-Morris intraparticle diffusion models. The maximum monolayer adsorption capacity of the GCA sorbent as obtained from the Langmuir adsorption isotherm was found to be 73.5 mg/g for fluoride. The v 2 and sum of squares of the error analysis were used to correlate the equilibrium isotherm models and kinetics. In addition, breakthrough curves were obtained from column flow experiments. The experimental results demonstrate that the GCA beads could be used for the defluoridation of drinking water through adsorption.

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