Preparation And Properties Of Carbon Nanotubes Surface Ion Imprinted Materials

The rapid growth of the human population and industrialization in the world has indirectly increased environmental problems such as water, air and land pollution. Amongst all, heavy metals can be considered as the most problematic pollutants. Once heavy metal ions inside the Biosphere, which will continue to exist and difficult to break down under normal circumstances. Thus, methods of removing heavy metals is concerned. Surface ion imprinting technology is a new technology to selectively remove certain metal ions, Which utilizes the specific structure hole on the surface of carriers, metal ion is absorbed selectively. This method is a hot research currently.This paper investigate the optimal conditions for preparing MWNTs-CO/PEI and Cu²⁺-IIP materials, study the adsorption characteristics and mechanism of Cu²⁺-IIP and Pb²⁺-IIP. Detail contents as follows:1. In this paper, the carboxyl carbon nanotubes is selected as carriers, using "Grafting onto" approach on its surface bonded macromolecular chains polyethyleneimine（PEI）, The functional monomer MWNTs-CO/PEI was prepared successfully. Discusses the affect of reactants ratio, reaction temperature and time for the grafting rate products, and the product was characterized by TEM, FTIR, TG methods. The results show that the optimum reaction conditions of chloride Carboxyl carbon nanotubes: 0.5g MWNTs-COOH and 25 ml SOCl2 under 60℃ refluxing 9h; The Optimal reaction conditions of bonding MWNTsCOCl and PEI is the mass ratio of MWNTs-COCl and PEI 1:6, under 70℃ react 7h. Products have the highest graft ratio reaching 40.40%. The surface of Carboxyl carbon nanotubes was coated by polymer about 20 nm, and generated the new functional group.2. Using “Grafting onto” prepared MWNTs-CO/PEI as functional monomer, and Cu²⁺ as template for preparing Cu²⁺-IIP materials. By single factor and orthogonal experiments to explore the optimal conditions for preparation, and products were characterized by TEM, FTIR methods. The results show that: the optimal preparation conditions is Template monomer ratio of 1:70, chelating p H=6.0, crosslinkers volume 1.0ml, crosslinking solution p H=8.0, crosslinking time 2h, crosslinking temperature 80℃, temperature chelating 70℃, and adsorption capacity can achieve 58.64mg/g. FTIR and TEM images illustrated Cu²⁺ was bonded with N atom of PEI again.3. By static adsorption experiments to study the Cu²⁺-IIP adsorption properties factors, choice and reuse identify. The results show that: When the initial concentration of Cu²⁺ is 90mg/l, Cu²⁺-IIP adsorption reaches saturation, the maximum adsorption capacity is 80.80mg/g, and is 3.1 times for Cu²⁺-NIP. The species adsorption is monolayer adsorption, and conform the Langmuir isotherm model. The best adsorption conditions is adsorption solution p H=5.0, adsorbent mass 0.02 g, under room temperature. This adsorption species belongs to the chemical adsorption, 60 min can reach adsorption equilibrium, which choice recognition and reuse rate are better.4. By static adsorption experiments to study the Pb²⁺-IIP adsorption properties factors, choice and reuse identify. The results show that: When adsorption solution p H=5.0, adsorbent mass 0.03 g and the initial concentration of Pb²⁺ is 45mg/l, Pb²⁺-IIP adsorption reaches saturation, the maximum adsorption capacity is 25.58mg/g, and is 2.47 times for Pb²⁺-NIP. The species adsorption is monolayer adsorption, and conform the Langmuir isotherm model. This adsorption species belongs to the chemical adsorption, 40 min can reach adsorption equilibrium, which choice recognition and reuse rate are better.