Competitive adsorption of Cu (II), Co (II) and Ni (II) from their binary and tertiary aqueous solutions using chitosan-coated perlite beads as biosorbent.

A new composite chitosan-coated biosorbent was prepared and was used for the removal and recovery of heavy metals from aqueous solution. In the present investigation, equilibrium adsorption characteristics of Cu (II), Ni (II), and Co (II) from their binary and tertiary solution on newly developed biosorbent chitosan-coated perlite beads were evaluated through batch and column studies. These beads were characterized by using FTIR, EDXRF and surface area analysis techniques. The effect of various biosorption parameters like effect of pH, agitation time, concentration of adsorbate and amount of adsorbent on extent of adsorption was investigated. The adsorption follows Lagergren first order kinetic model. The equilibrium adsorption data were fitted to Freundlich and Langmuir adsorption isotherm models and the model parameters were evaluated. Both the models represent the experimental data satisfactorily. The sorbent loaded with metal was regenerated with 0.1N NaOH solution. Furthermore the column dynamic studies indicate the re-usage of the biosorbent.

Biosorption of phenol and o-chlorophenol from aqueous solutions on to chitosan-calcium alginate blended beads.

Beads of chitosan-sodium alginate are prepared from naturally occurring biopolymers, chitosan (a cationic polysaccharide) and sodium alginate (an anionic polysaccharide). These beads are treated with CaCl(2) in order to improve the stability as well as the sorption capacity of the biosorbent. The resulting chitosan-alginate beads are characterized by BET surface area analysis, Fourier transformer infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (WXRD) techniques. The efficiency of the biosorbent is studied by measuring the uptake using the equilibrium batch technique and breakthrough curves obtained from column flow experiments. The effect of pH, contact time, initial concentration of adsorbate and amount of biosorbent on adsorption capacity of the biosorbent is investigated. The equilibrium adsorption data are fitted to first-order and second-order kinetic equations, and to Weber-Morris model. The Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherm models are used for the description of the biosorption process. Further, column break-through curves are obtained and the sorbent loaded with phenol and o-chlorophenol is regenerated using 0.1M NaOH solution. The experimental results suggest that the chitosan-calcium alginate blended biosorbent is effective for the removal of phenol and o-chlorophenol from an aqueous medium.