Preparation of fructose‐mediated (polyethylene glycol/chitosan) membrane and adsorption of heavy metal ions

Chitosan is an efficient metal chelater, but its practical use is limited due to the stability in acid solutions, adsorption capacities. In this study, we attempt to find a new pH‐dependent adsorbent based on fructose‐mediated chitosan/PEG membrane and examines several experimental parameters relative to their formation and characteristics. The membrane was characterized in terms of their fourier transforms infrared spectroscopy‐attenuated total reflectance (FTIR‐ATR) spectra, X‐ray diffraction (XRD) analysis, surface morphologies, tensile strength, mediating degree analysis, and swelling behavior at pH 3 and 6 medium. To estimate the potential of these membranes as a biosorbent, the capability and behavior for the adsorption of heavy metal ions were investigated using Lead ions as a model compound. FTIR‐ATR result showed that the Schiff's base reaction was favor formed in high pH condition. Swelling study showed that the swelling degree of homogeneous mediated membrane decreases as the pH of the final fructose‐mediated chitosan/PEG gel increase, which was demonstrated by mediating degree analysis. Low crystallinity of fructose‐mediated membranes is responsible for its sorption efficiency. With increasing the amount of fructose in the chitosan/PEG there is a proportionality of the adsorption capacity except that the high fructose content (10 wt %). The pH 6 treated 5 wt % fructose‐mediated membrane has a maximum sorption capacity to about 185 mg/g. The adsorption isotherms could be well fitted by the Langmuir equation. The results showed the potential applicability of fructose‐mediated chitosan/PEG membrane as a biosorbent for metal recovery. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007