Preparation of Iminoacetic Acid-type Composite Chelating Material IAA-PEI/SiO₂and Preliminary Studies on Chelating Adsorption Property towards Heavy Metal Ions

Abstract

Polyamine polyethyleneimine (PEI) was first grafted on the surfaces of micro-sized silica gel particles in the manner of the coupling graft (the manner of "grafting to"), forming the grafting particles PEI/SiO 2 . Subsequently, via a polymer reaction, the nucleophilic substitution reaction between the primary and secondary amino groups of the grafted PEI macromolecule and chloroactic acid (CAA), iminoacetic acid groups were bonded onto the grafted PEI chains, and an iminoacetic acid (IAA)-type composite chelating material, IAA-PEI/SiO 2 , was formed. In this work, the preparation process of IAA-PEI/SiO 2 particles was mainly researched, and the effects of the main factors on the polymer reaction, i.e., the nucleophilic substitution reaction, were examined emphatically. The adsorption behavior of IAA-PEI/SiO 2 particles towards several kinds of heavy metal ions was preliminarily evaluated. The experiments results show that it is feasible to introduce IAA groups onto PEI/SiO 2 particles via the substitution reaction between CAA and the amino groups of the grafted PEI. The reaction rate is affected greatly by the feed ratio of the amino group of PEI to CAA, so the substitution reaction between CAA and the amino groups of the grafted PEI is a bimolecular nucleophilic substitution reaction (S N 2). The reaction temperature and the used amount of acid-acceptor NaHCO 3 affect the bonding rate of IAA groups greatly. The fitting temperature was 60 • C, and 1:1 of the molar ratio of NaHCO 3 to CAA was an appropriate amount of acid-acceptor NaHCO 3 . Under the above optimal reaction conditions and with 3:1 molar ratio of amino group of PEI to CAA, 72% of the IAA group bonding rate (it is based on the hydrogen atoms in the primary and secondary amino groups of the grafted PEI) in 8 h can be reached. The composite chelating material IAA-PEI/SiO 2 possesses a strong chelating adsorption ability for heavy metal ions because of the increase of the ligands and formation of stable five-membered chelate rings.

Synthesis of amphiphilic block copolyamines via click reaction

“…Polyamines or aminogels are used to extract heavy metal ions, nanoparticles and anionic metal species through electrostatic interactions [10][11][12][13][14][15][16][17]. Polymers such as polyethylenimine (PEI) and polyallylamines with large number of primary and secondary amino groups exhibit good extraction ability for heavy metals [18][19][20].…”

Removal characteristics of two anionic dyes by a polyethylenimine/poly(N,N-dimethylaminoethyl methacrylate) gel

“…For example, a new adsorption material, PEI-SiO 2 , was prepared by connecting polyethyleneimine (PEI) to the surface of silica gel, which was found to have ideal adsorption capacity for Cr(VI), Cu(II), Zn(II), and Cd(II). 7 Aer the modication of the material by a quaternary amine, a new adsorption material named Q PEI-SiO 2 could be prepared to adsorb the chromate ions. 8 Moreover, in the study by Tokuyama et al, 9 the adsorption amounts of Pt(IV) and Au(III) ions on the PDMAEMA gel were 0.2542 mmol g À1 and 0.2351 mmol g À1 , respectively.…”

Solution processable polyamines via click chemistry for water purification

“…[15][16][17][18][19][20][21][22] Polyethylenimine (PEI) with large number of primary and secondary amino groups exhibits good sorption ability for heavy metals. 23,24 1,2,3-Triazole group, a versatile functional heterocycle unit formed by click reaction, has been used in supramolecular chemistry for coordination with anionic, neutral and cationic guest molecules. 25 Recently, we reported the synthesis and characterization of polyamines for the removal of dissolved metallic nanoparticles from water.…”