Adsorption and desorption of zinc(II) on water‐insoluble starch phosphates

Abstract Water‐insoluble starch phosphates (SPs) with different contents of phosphate groups were used as adsorbents of Zn(II). The effects of the adsorption time, dosage of adsorbents, and pH on the removal of Zn(II) by SPs were thoroughly studied. The results showed that the water‐insoluble SPs were effective adsorbents for Zn(II) removal. The optimal adsorption effect was achieved at pH = 4.0, and the adsorption equilibrium data agreed well with the Langmuir isotherm model with a maximum adsorption capacity of 2.14 mmol/g. Furthermore, the desorption process and reusability of the adsorbents were studied. HCl (0.5 N ) was found to be an appropriate desorption solution to desorb Zn(II) ions from the adsorbents. After three adsorption/desorption cycles, the Zn(II) adsorption capacities of three SP samples decreased from 0.92, 1.23, and 1.44 to approximately 0.72, 1.02, and 1.29 mmol/g, respectively, and all the desorption percentages were greater than 93%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009