Synthesis And Properties Of Polyamine-bridged Polysilsesquioxanes

Bridged Polysilsesquioxanes (BPS) as a new organic-inorganic hybrid materials arousedpeople’s great attention in recent years. In this paper, fourteen kinds of Polyamine-Bridgedpolysilsesquioxanes and eight kinds of Cu(II) ion imprinted Polyamine-Bridgedpolysilsesquioxanes were prepared by sol-gel method, respectively. These adsorptionmaterials were systematically characterized by X-ray diffractometry (XRD), infraredspectroscopy (FT-IR), elemental analysis, scanning electron microscope(SEM), porousstructure analysis and thermogravimetry analysis. And their adsorption and selectivityproperties were investigated for metal ions.Using3-glyciddoxypropyltrimethoxysilane (GPTS), ethanediamine(EDA) ordiethylenetriamine (DETA) as raw materialas, EDA-bridged monomer and DETA bridgedmonomer were prepared. Using hexadecyl trimethyl ammonium bromide (CTAB) asporogenic agent, EDA-BPS, DETA-BPS, EDA-BPS-C and DETA-BPS-C were prepared bysol-gel method, respectively. Several metal ions, such as Hg(II), Ag(I), Cd(II), Cu(II) andPb(II), were chosen as representatives to investigate the relationship between adsorptionproperties and the pore structure of these materials. The experiments results showed that thestability mesoporous structure, higher specific surface area and pore volume of EDA-BPS-Cand DETA-BPS-C increased the adsorption capacity of EDA-BPS-C and DETA-BPS-C formetal ions. The kinetics data indicated that the adsorption process of EDA-BPS andDETA-BPS was governed by the film diffusion, the adsorption process of EDA-BPS-C andDETA-BPS-C was governed by intraparticle diffusion before20minutes and the adsorptionprocess of EDA-BPS-C and DETA-BPS-C was governed by film diffusion after20minutes.The adsorption process of four adsorption materials for Hg(II) was followedpseudo-second-order rate model. The isotherm adsorption results revealed that the Langmuirisotherm was the best fitting model to describe the equilibrium adsorption of four adsorptionmaterials for Hg(II). Thermodynamic analys is revealed that the adsorption processes of Hg(II)on the overall adsorbents could be considered as spontaneous， endothermic, entropyincrease,and the solid-liquid interface chaos degree increased.In the co-condensation process a certain amount of tetraethylorthosilicate (TEOS) wasintroduced. Different DETA-bridged monomer/TEOS molar ratios of1:2,1:4,1:6,1:10and 1:20were adopted in the batch experiments. Ten kinds of DETA-Bridged polysilsesquioxanes,DETA-BPS-T-X(X refers to2,4,6,10,20) and DETA-BPS-T/C-X(X refers to2,4,6,10,20),were prepared, respectively. The adsorption capabilities of such adsorption materials towardsHg(II), Ag(I), Cd(II), Cu(II) and Pb(II) were studied to probe the relationship betweenadsorption properties and the volume of TEOS. The experimental results indicated that thespecific surface area increased with the increase of the DETA-bridged monomer/TEOS molarratios. Adsorption capacity that all kinds of adsorption materials adsorb metal ions decreasedfirstly and increased secondly and decreased finally. DETA-BPS-T/C-10processed welldesorption and regeneration capacities.Molecular imprinting technique was introduced into the synthetic process of BPS. Eightkinds of Cu(II) ion imprinted Polyamine-Bridged polysilsesquioxanes, Cu(II) ion imprintedEDA-Bridged polysilsesquioxanes (EDA-BPS-Cu, EDA-BPS-T/C-Cu, EDA-BPS-T/A/C-Cu)and Cu(II) ion imprinted DETA-Bridged polysilsesquioxanes(DETA-BPS-Cu,DETA-BPS-T/C-Cu, DETA-BPS-T/A/C-Cu, DETA-BPS-T-10-Cu, DETA-BPS-T/C-10-Cu),were synthesized by using Cu(II) as imprinted ion. We investigate the adsorption properties ofthese materials for Cu(II). The effects of the addition of Cu(II), TEOS, APES and CTAB onthe structure and adsorption performance of these materials were studied. The resultssuggested that the presence of TEOS, APES, and CTAB played a good role in supportingframe. Adsorption selectivity experiments indicated that Cu(II) ion imprintedPolyamine-Bridged polysilsesquioxanes possessed excellent adsorption property to Cu(II)ions, offering potential applications in recovery of Cu(II) from multi-ionic aqueous systems.