Adsorption of Hg(II) from Aqueous Solutions by Two Aniline Copolymers

Abstract

Two derivative copolymers of polyaniline, poly(aniline-co-2,4-diaminophenol) (PANDAP) and poly(aniline-co-o-aminophenol) (PANOA) were synthesized and used for adsorption of Hg(II) from aqueous solutions. The results show that both PANDAP and PANOA have excellent adsorption ability for Hg(II) and the sorption process follows the Langmuir model and the pseudo-second-order kinetic model well. It was found that the solution pH values had a major impact on Hg(II) adsorption by PANDAP with optimal removal observed at pH 5-7 and the maximal adsorption capacity was more than 800 mg g^-1 at pH 5.5. Although PANOA has a smaller maximal adsorption capacity (about 200 mg g^-1), its adsorption process was independent of pH and the Hg(II) removal efficiencies by PANOA were all over 90 % in a wide pH range of 3-9. The results also proved that these two adsorbents could be effectively desorbed in HCl solution (0.1 mol L^-1) with 0.5 % sulfocarbonide for reuse.