Removal of Heavy Metals from Aqueous Solution Using Starch Nanocrystals

In this paper, the starch nanocrystals (SNCs) were prepared by enzymatic pre-hydrolysis combined with sulfuric acid hydrolysis and used to remove the heavy metal ions by adsorption. The optimum preparation conditions were determined according to the enzymatic hydrolysis kinetics, XRD, and particle size analysis results. The adsorption capacity of SNCs for Zn(II), Cu(II), and Fe(II) in an aqueous solution was studied by changing the pH, contact time, and initial concentration of metal ions using the batch equilibrium technique. When the initial concentration of metal ions was 200 mg/L, the maximum adsorption capacity of SNCs for Zn(II), Cu(II), and Fe(II) was 46.13 mg/g, 35.83 mg/g and 17.49 mg/g, respectively. The results also showed that the adsorption of Zn(II), Cu(II), and Fe(II) by SNCs conformed to the second-order kinetics and the Freundlich adsorption isotherm.