Chitosan and Chitosan Derivatives as Chelating Agents - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 9

methylpiperazin-1-yl) methyl] benzaldehyde, (L) (Figure 5) by means of condensa-
tion. The new polymer was characterized by various techniques such as elemental,
spectral, and structural analysis. Its kinetics of adsorption was evaluated utilizing
the pseudo first order and pseudo second order equation models and the equilibrium
data were analyzed by Langmuir isotherm model. The CTSL showed good adsorp-
tion capacity for the metal ions investigated in the order Cu(II) > Ni(II) > Cd( II)
≥Co ≥Mn(II) > Fe(II) > Pb(II) in all studied pH ranges due to the presence of many
coordinating moieties present in it. The binding capacities of the polymer for Mn, Fe,
Co, Cu, Ni, Cd, and Pb were found to be 19.8, 18.4, 22.4, 56.5, 34.63, 46.1, and 51.8
mg/g, respectively, and were higher than the values obtained for unmodified chitosan.
The higher adsorption capacity toward Cu(II) ions than other metal ions studied, in-
dicates that it shows selectivity toward Cu(II) ions in aqueous solution and hence it
can be used to extract Cu(II) ions from the industrial waste water (Krishnapriya and
Kandaswamy, 2010).
Figure 5. New Vanilin-based Ligand (L) (Krishnapriya and Kandaswamy, 2010).
Recently (Zalloum et al., 2009), the adsorption of Cu(II) ions onto chitosan de-
rived Schiff bases obtained from the condensation of chitosan with salicyaldehyde,
2,4-dihydroxybenzaldehyde and with 4-(diethylamino) salicyaldehyde was investi-
gated. The isothermal behavior and the kinetics of adsorption of Cu(II) ions on these
polymers were investigated. Various factors that affect the adsorption process were
also explored. The highest Cu(II) ions uptake was achieved at pH 7.0 and by using so-
dium perchlorate as an ionic strength adjuster. Adsorption isothermal equilibrium data
could be clearly explained by the Langmuir monolayer model. The experimental data
of the adsorption equilibrium from Cu(II) solution correlates well with the Langmuir
isotherm equation. Moreover, the adsorption kinetics of Cu(II) ions on these chitosan
derived Schiff bases indicated that the kinetic data correlated well with the pseudo-
second order model.