Study On Preparation Of Ion Imprinted Polymers And Their Application In Selective Removal Of Cobalt Ion And Arsenite Ion From Wastewaters

The environmental pollution of heavy metal ions has already become serious problems that influence the survival environment of citizen and development of social economy. Among the water pollution, the heavy metal cobalt ion and arsenite ion are prominent issues at present. Therefore,in this paper, we developed several new specificity nano adsorbent materials by using ion imprinting technology, applied them to remove harmful heavy metal cobalt ion and arsenite ion from waste water. The details are summarized as follows:1. A magnetic ion-imprinted polymer(Co(II)-IIP) was prepared for the selective removal of cobalt ions from aqueous samples was synthesized by surface imprinting technique using 1- vinylimidazole as monomer, ethyleneglycol dimethacrylate as cross-linking agent, and Co(II) ion as template. The Co(II)-IIP was characterized by scanning electron microscopy, and the sizes of the Fe3O4, Fe3O4@Si O2, Co(II)-IIP, and NIP were 88, 430, 750, and 792 nm, respectively. Co(II)-IIP showed higher selectivity and hydrophilic than that of NIP. The experimental data fits well with the Langmuir adsorption isotherm. The maximum Co(II)-sorption capacity is 23.09 mg/g and 16.88 mg/g for Co(II)-IIP and NIP, respectively. The relative selectivity coefficient of Co(II)-IIP for Co(II)/Cu(II), Co(II)/Cd(II), Co(II)/Zn(II), and Co(II)/Pb(II) are 1.33, 2.51, 1.29, and 1.41, respectively. In addition, the spent Fe3O4@Si O2-IIP can be refreshed by simple washing with aqueous HNO3 solution, and there is no significant decrease in adsorption capacity after a test of up to four cycles, demonstrating that the Co(II)-IIP is stable and reusable. In addition, Co(II)-IIP can remove Co(II) ion with higher 96% from wasterwater, which confirms it is good adsorbents for the removal of Co(II).2. There is a great difficulty in the synthesis of anionic imprinted polymers, because the functional monomer of strength force with template ionic is rare. We synthesized a new type of cation cyclic compound with imidazole. Bromomethyl methyl etherwas slowly added into the sulfuric acid solution with acridine, the as-obtained mixture was aged(under vigorous agitation) at 50 for ℃ 24 h, finally the 4,5-bis(bromomethyl) acridine was further purified by silica gel chromatography. A solution of 1-(1H-imidazol-1-ylmethyl)-1H-imidazole and 4,5-bis(bromomethyl) ancridine in dry acetonitrile was stirred at 90℃ for 48 h. The precipitates were filtered under hot solution. The tetrabromide-4,5-bis(methylene-bis-imidazole)acridine was recrystallized from CH3 OH. The structurally of related compounds were confirmed by NMR spectroscopy.3. We had prepared arsenite ion imprinted polymers(IIP) with bulk polymerization. The IIP were confirmed by the specific surface area(BET), the specific surface area and average pore diameter of IIP were 434.04 m2/g, 6.69 nm, respectively. The absorption performance of IIP was investigated. It was showed in the results that it possessed good selectivity, high adsorption capacity in aqueous solution. The relative selectivity coefficient of IIP for HAs O32-/Cl-, HAs O32-/SO42-, HAs O32-/HPO42-, HAs O32-/NO3-, and HAs O32-/Mo7O246- are 1.03, 1.95, 2.55, 1.52, and 2.51. The results showed IIP could remove Co(II) ion with near 100% removal efficiency from wasterwater. This results also verified that IIP is an excellent and selective adsorbent for HAs O32-.