Polyacrylamide grafted attapulgite (PAM-ATP) via surface-initiated atom transfer radical polymerization (SI-ATRP) for removal of Hg(II) ion and dyes

Well-defined polyacrylamide was grafted successfully from the fibrillar clay, attapulgite, by a three-step process: (i) the γ-aminopropyltriethoxyl silane was chemical-bonded onto the surfaces of the attapulgite; (ii) the surface amino groups were amidated with bromoacetylbromide; and (iii) the bromo-acetamide modified attapulgite was used as macro-initiator for the surface-initiated atom transfer radical polymerization (SI-ATRP) of acrylamide with the catalyst of the complex of 1,10-phenanthroline and Cu(I)Br. The percentage of grafting (PG%) was found to increase linearly with the increasing of the polymerizing time and that of 21.4% was achieved after the SI-ATRP in aqueous solution at 90 °C for 6 h. The graft polymerizations exhibited the characteristics of a controlled/“living” polymerization. The product, polyacrylamide grafted attapulgite (PAM-ATP), had been characterized with elemental analysis (EA), Fourier transform infrared (FT-IR) spectroscopy analysis, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). It's adsorption properties towards the heavy metal ion (Hg(II)) and dyes (methylene blue (MB) and methyl orange (MO)) were also studied preliminarily.