Functionalized nano-starch prepared by surface-initiated atom transfer radical polymerization and quaternization.

Functionalized nano-starch particles, designed for the adsorption of heavy metals in wastewater, were prepared by a nano-processing, a halogenated grafting modification, a grafting copolymerization of surface-initiated atom transfer radical polymerization (SI-ATRP) and a quaternized modification of native corn starch. The influence of the synthesis process variables, such as the hydrolysis time, the concentration of monomer, the molar ratio of copper bromide (CuBr) to 2, 2'-bipyridine (bpy) and the graft copolymerization temperature on the properties of the products were studied. The morphology, molecular structure, crystalline structure of the functionalized nano-starch and its derivatives were characterized by Fourier transform-infrared spectroscopy (FT-IR), H nuclear magnetic resonance (H-NMR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The functionalized nano-starch showed strong adsorption for chromate and could be used as an effective wastewater treatment agent. Its adsorption capability could be almost totally regenerated by an easy process.