Preparation And Properties Of Epoxy Activated Chitosan

With the rapid development of industrialization, more attention must be paid on environmental protection. The industrial wastewater contains many pollutants including protein, heavy metal ion and organic dye. Chitosan has obtained wide interest due to its adsorption capabilities on those pollutants.The epoxy activated chitosan (EACT) with high stability and insolubility was prepared by crosslinking chitosan and epoxy chloropropane, because the degradation of native chitosan occurs in acid environment. The structure and morphological feature of EACT were analyzed using SEM, TGA, XRD and FTIR. The results show that the modified chitosan is more stable and has internal porous structure, enhancing the adsorption performance. Then, the adsorption properties of protein, heavy metal ion and organic dye on the resulting EACT were investigated together with the adsorption mechanism. For the adsorption of protein, the adsorption conditions were optimized using bovine serum albumin (BSA) as simulation system. The maximum adsorption rate for BSA is88.7%under the optimum conditions (pH5.0, EACT dosage1.3g, initial BSA concentration0.2mg·mL-1). The adsorption process appears to follow the pseudo-second order kinetics equation and Freundlich adsorption equation. For the adsorption of Pb (Ⅱ), the adsorption process follows the pseudo-second order kinetics equation and obeys the Langmuir monolayer adsorption. The enthalpy change (ΔH0), entropy change (ΔS0) and apparent activation energy of the adsorption of pb(II) are negative, and the negative ΔG0values indicate the adsorption process was exothermic and spontaneous. For the adsorption of organic dye, the adsorption processes of toluidine blue and methyl orange were studied comparatively. The decoloration rate for toluidine blue and methyl orange are83.7%and88.6%, respectively, and the adsorptive processes conform to the pseudo-second order kinetics equation.These results suggest that EACT has good physical and chemical stability, high adsorption removal capability of pollutants from wastewater and reusability,which indicates that the EACT may be a candidate of novel biosorbents used in wastewater treatment.