Preparation and characterization of thiol- and amino-functionalized polysilsesquioxane coated poly(p-phenylenetherephthal amide) fibers and their adsorption properties towards Hg(II)

Two types of fibrous adsorbents, thiol- and amino- functionalized polysilsesquioxane coated poly(p-phenylenetherephthal amide) (PPTA) fibers (PPTA-PAPSQ and PPTA-PMPSQ), were prepared via the in situ condensations with aminopropyltriethoxysilane (APTES) and mercaptopropyltriethoxysilane (MPTES) on the surface of PPTA fibers, respectively. Their structures were characterized by FTIR, FE-SEM, XPS, XRD, TG, Elemental analysis, and pore structure analysis. The effect of the ratio of reactants on the structures of these two modified fibers was investigated. The results of nitrogen adsorption-desorption isotherms revealed that the polysilsesquioxane coating on the surface of PPTA-PMPSQ samples exhibited open meso- or macroporous features, while those on the surface of PPTA-PAPSQ samples formed dense gel structures. Moreover, Hg (II) was chosen as a representative to evaluate the adsorption properties of PPTA-PAPSQand PPTA-PMPSQ samples. The results showed that the adsorption processes of Hg(II) followed well pseudo-second-order model onto the two series adsorbents. The Langmuir was the better-fit model to predict the experimental data. The theoretical saturation adsorption capacities of polysilsesquioxanes coated on the PPTA-PAPSQ and PPTA-PMPSQ adsorbents can reach 3.52-10.64 mmol g(-1) and 7.43-10.22, mmol g(-1), respectively. The result showed that PPTA-PAPSQ and PPTA-PMPSQ adsorbents can selectively adsorb Hg(II) from binary component metal ion systems. (C) 2017 Elsevier B.V. All rights reserved.