Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

摘要

A novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon ( an acrylonitrile-based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(Ⅲ), Pt(Ⅳ), Pd(Ⅳ) and Ir (Ⅳ) ions from solution of samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/min at pH 2, and can also be desorbed with 15 mL of 4 mol/L HCl + 3% thiourea from the fiber column with recoveries of 96.5%-100%. The chelating fiber can be reused for ten times, the recoveries of these ions are still over 92%,and hundred to thousand times of excess of Fe(Ⅲ), Al(Ⅲ),Ca(Ⅱ), Mg(Ⅱ), Ni(Ⅱ), Mn(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), and Cd (Ⅱ) cause no interference on the determination of the analyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80 mmol/g. The relative standard deviations for the determination of 20.0 ng/mL each of Au(Ⅲ), Pt(Ⅳ), Pd(Ⅳ) and Ir (Ⅳ) are in the range of 0.7%-3.0%. The recoveries for test from standard additions to real solution sammples are between 96% and 100%. The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.