Preparation And Adsorption Properties Of A Novel Chelating Resin From Chitosan Derivative

The chelate resin has been developed in many fields, which is based on the ion exchangeresin. The chelate resin can form a stable coordination bond with heavy metal ions. Due to thehigher ion selectivity, good capacity of adhesion, excellent viability, stability, and low cost,etc., it was widely employed to absorbe the heavy metal ions from waste water. Among,natural resin-chitosan can be considered as a good candidate in the appliction of absorptionheavy metal ions from waste water.In this article, a novel biodegradable polymer crosslinked chitosan-polyaspartyl resinwas synthesized by combinating polyaspartate polymer and chitosan with crosslinkerglutaraldehyde. Every synthetic technology was optimized, and optimal technologicalparameters were determined. The disulfide group (-S-S-) was introduced into the polymer,which could increase the identification of ion-selectivity. The structures of all syntheticpolymers were characterized by NMR, FTIR and Raman spectroscopy, SEM etc. Variousfactors affecting the uptake behavior such as contact time, adsorbent dosage, pH and initialconcentration of the metal ions were investigated to evaluate the adsorption properties of theresin toward Co(II), Ni(II), Pb(II) and Hg(II) ions. The result shown that the reasonablecontact time was about8h, the initial concentration of heavy metal ions was adaptive at lessthan150mg/L, the values of optimal pH were6.0,6.0,5.0,4.0, the suitable doses were2g/L,2g/L,1g/L,1g/L, respectively.The kinetic parameters were evaluated utilizing the pseudo-first-order model, pseudo-second-order model and intraparticle diffusion model. The adsorption kinetics followed thepseudo-second-order model for all systems studied, evidencing chemical sorption as therate-limiting step of adsorption mechanism. The equilibrium data were analyzed using theLangmuir, Freundlich, and Dubinnin-Radushkevich isotherm models. The result shown thatLangmuir isotherm could well fit the equilibrium data of adsorption, which indicated thatadsorption process was monolayer favorable adsorption. The adsorption process for Co(II),Ni(II), Pb(II) and Hg(II) ions belonged to chemical adsorption, which was estimated byDubinnin-Radushkevich isotherm equation.and the maximum adsorption capacities were48.7,57.0,152.2and170.6mg/g, respectively. And In addition, the thermodynamic studiestestified that the adsorption processes of heavy metals on the resin were endothermic and spontaneous in nature. The results of regeneration test showed that the resin still maintained athigh adsorption level after repeatedly used and come to be a good potential reusableadsorbent.