Synthesis And Properties Of Multi-functional Chelating Resin

The new kind of functional copolymer materials were synthesized, whichskeleton was based on the cross-linked co-polymer and contained quaternaryammonium cation and salicylaldehyde imine (Schiff base) in this paper. Thefunctional copolymer materials were used as the chelating resins with hydrophilicproperties and chelating groups, which can have the priority complex reactions withheavy metal ions to form metal complexes. They are widely applied in the seperation,detachment, determination and recovery of the heavy metal ions from waters due totheir high selectivity, high adsorption capacity and quick adsorption rates. The poly(4-vinyl pyridine-co-divinylbenzene) was prepared with4-vinyl pyridine as functionalmonomer and divinylbenzene as a cross-linker through suspension polymerization.Then PVP-co-DVB were functionalized to give five types of chelating resins(PVP-QA-SXX) which loaded quaternary ammonium salts and Schiff bases.Comparative studies of PVP-QA-SXX and the small molecular model compounds hadbeen made in preparation, physicochemical properties, adsorption properties andadsorption characteristics for Pb(Ⅱ).(1)The five small molecular model compounds (Py-SOA, Py-STA, Py-SGA,Py-SPA and Py-SPyA) had been prepared with pyridine,5-cholromethylsalicyla-ldehyde, thiosemicarbazide, glycine, anthranilic acid, para-aminobenzoic acid and2-amino pyridine as the raw materials. It can be confirmed that all Py-SXX were newcompounds after investigation.(2)The physical properties, UV-Vis spectra and chromogenic reactions ofPy-STA, Py-SGA, Py-SOA, Py-SPA and Py-SPyA with eight kinds of heavy metalions were tested respectively. The results showed that the five small model moleculeshad changed their colors obviously when reacted with the heavy metal ionsrespectively.(3)PVP-co-DVB was prepared by suspension polymerization. ThenPVP-co-DVB was functionalized to give five novel chelating resins (PVP-QA-STA,PVP-QA-SGA, PVP-QA-SOA, PVP-QA-SPA and PVP-QA-SPyA) containingquaternary ammonium salts and Schiff bases, which possesses good thermal stabilityand pore performance.(4)The factors influenced the resin’s diameter and pore performance includingstirring speeds, dispersant usage, crosslinker degree and porogen usage had beenstudied. It can be confirmed that dispersant usage and stirring speeds had remarkable influences on the resin’s diameter; and crosslinker degree and pore forming agentcontent also had remarkable influences on the resin’s pore performance and specificsurface area.(5)This thesis gave the studies on adsorption capacities of PVP-QA-SXX for theheavy metal ions, which Pb(Ⅱ) had been selected as the target ions. The factorsinfuence the uptake of Pb(Ⅱ) such as pH, initial concentration of Pb(Ⅱ), shakingtime and temperature were investigated systematically by batch experiments. Theresults indicated that PVP-QA-SXX had high adsorption capacities for Pb(Ⅱ). ThepH value has significant effect on the ion adsorption capacities. It was also indicatedthat the heavy metal ions adsorption on the resins were promoted by an exothermicreaction, which decreases the confusion and occurred spontaneously, and theadsorption process fits Langmuir model well. The equilibrium adsorption uptake timewas in30minutes. The ligand chemical process, hydrogen bond and vander Waalsforce complement the adsorption process.