Based On The Atrp Preparation Of A New Type Of Chelating Resin And Its Adsorption Properties For Heavy Metal Ions

Chelating resin is an important functional material, which is widely used in separation and enrichment of metal ions. At present, chelating resin prepared by traditional method has low density of functional groups and thus exhibit low adsorption capacity. The introduction of the new "grafting from" surface modification technology provides the possibility for improvement of the density of functional groups and adsorption capacity, and might become a new method to prepare chelating resin with high adsorption capacity. In this study, chloromethylated polystyrene was modified by surface-initiated atom transfer radical polymerization to prepare new chelating resin, and the adsorption properties of new resin to three heavy metal ions were investigated. The main contents and conclusions are as follows:1. A new chelating resins was prepared by grafting poly(glycidylmethacrylate)(PGMA) on chloromethylated polystyrene via atom transfer radical polymerization(ATRP) methodology with CuBr/bpy complex as catalyst, and followed by the reaction with iminodiacetic acid (IDA). The structure of chelating resin was characterized using fourier transform infrared spectroscopy, elemental analysis, surface area and porosity analyzer. An increase in the polymerization time leads to the increases in GMA grafting yield and IDA binding amount, indicating that ATRP can control the content of monomers and functional groups.2. Adsorption experiment was carried out to investigate the adsorption property of the novel chelating resin to Ni(Ⅱ), Cu(Ⅱ) and Pb(Ⅱ). The results were obtained as following:①he adsorption of Ni(Ⅱ), Cu(Ⅱ) and Pb(Ⅱ) fitted Langmuir monolayer adsorption model, with the maximum adsorption capacities of1.29,1.19and0.83mmol/g at30℃, respectively, which is higher than the same type of the reported absorbent;②he adsorption equilibrium reached within250-300min and the adsorption kinetics of metal ions fitted the second-order kinetic model;③When the optimal pH is5.0, the maximum adsorption capacity can be obtained. With the temperature increasing, the adsorption capacity of the investigated three ions increase, indicating that the adsorption was endothermic process.④The adsorption of the chelating resin to Ni(II) was investigated with dynamic method. The results showed that the cumulative adsorption capacity to Ni(II) is0.97mmol/g. The chelating resin could regenerated with2mol/L hydrochloric acid. After adsorption-desorption reused more than six times, the adsorbent still gave an adsorption rate of93%.