Adsorption of heavy metal ions by poly[n-isopropylacrylamide] crosslinked with triethy-lenetetramine

Abstract

A new copolymer poly[N-isopropylacrylamide-co-maleic acid] crosslinked with triethylenetetramine was prepared by free radical polymerization. The percent mole ratio of N-isopropylacrylamide to maleic acid was fixed at 65:35 and using ammonium persulphate as an initiator. The copolymer was synthesized at the temperature ranging of 60-80 °C followed by a heat-induced amidation crosslinking reaction at 145 °C. The copolymer was characterized by Fourier transforms infrared spectroscopy. Adsorption behavior of lead(II), copper(II) and chromium(III) ions was examined by bath method. The result showed that the copolymer crosslinked with triethylenetetramine had more adsorption capacity than copolymer without triethylenetetramine. The optimum pH value for the adsorption of lead(II) Cu(II) was 5 and 4-5 for Cr(III) when using a rod shape copolymer (0.7 cm diameter and 1 cm length). The adsorption equilibrium reached within 2, 5 and 7 hours for Pb(II), Cu(II) and Cr(III), respectively at 28-30 °C. The desorption of Pb(II), Cu(II) and Cr(III) ions equilibria reached within 0.5-1 hour at temperature lower 25 °C by 15% (v/v) HCl.