• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.871-875
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• 1999

We calculated the characteristics of a phosphoric cation exchanger and studied on an accurately computable method to determine the ion exchange capacity for type of potentiometric titration curve. The ion exchanger was prepared by phosphorylation of a styrene-divinylbenzene copolymer with 4% crosslinking. The ion exchange capacity is 5.7 meq/g. The experimental pK values versus ${\mathit{x}}$ in phosphoric cation exchanger can be expressed as a linear equation. The ${\Delta}pK$ values were obtained from the slope of linear equation. The ${\Delta}pK$ values are the differences of antilogarithms(pK) values of the apparent equilibrium constant at complete and zeroth neutralization of the ion exchanger. Also the experimental pK values at ${\mathit{x}}=0.5$ were accorded well with theoretical data. And when it is titrated with NaOH and $Ba(OH)_2$ solutions, a good agreement between experimental and theoretical pK values for various ${\mathit{x}}$ was seen in all the potentiometric titration curves. We knew that the inflection point of potentiometric titration curve in the case of divalent ions are changed much large than that for monovalent ions. If the relation between g values and ${\partial}pH/{\partial}g$ was plotted to the Lorentz distribution curve, ion exchange capacity can be accurately evaluated.

• Polymer(Korea)
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• v.27 no.3
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• pp.242-248
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• 2003

PP-g-(AN/Sty) was synthesized by grafting with acrylonitrile (AN) and styrene (Sty) onto PP staple fiber using an electron beam accelerator and followed by amidoximination and phosphorylation. Mole fraction of AN in the graft chain increased with the increase of the AN content in the monomer mixture. The highest AN grafting yield of 45% was obtained at a monomer ratio of 40 vol% AN/60 vol% Sty. Mole fraction of AN in the graft chain decreased with the increase of methanol amount used its solvent. As reaction temperature increased, the grafting yield of copolymer increased and reached equilibrium at 50$^{\circ}C$. Amount of amidoxime group in fibrous ion exchanger was increased as increasing amount of hydroxylamine, and the maximum content of amidoxime group was observed at 5.8 mmol/g with the 9 wt% hydroxylamine concentration. Content of phosphorous group in fibrous ion exchanger increased up to 0.5 N phosphoric acid concentration, and then leveled off. The adsorption ability of the copolymer for uranyl ion by the chelating adsorbents was in the following order : bifunctional PP-g-(AN/sty) > amidoximated PP-g-(AN/Sty) > phosphorylated PP-g-(AN/Sty).