Separation Science and Technology, Vol.39, No.4, 941-957, 2004
Synthesis, characterization, and metal extractive behavior of functionalized AXAD-16 polymeric matrix using oxyacetone acetamide
A new metal chelating polymer has been synthesized using Amberlite XAD-16 (AXAD-16) polymer matrix, chemically modified using oxyacetone acetamide as the functional group. The resin was characterized by Fourier transform-infra red (FT-IR) studies, elemental analysis, and thermogravimetric analysis. The metal extractive efficiency of the functionalized resin matrix was examined and it was found that the synthesized resin showed high selectivity and preconcentrating ability toward trace heavy metal ions. Various physiochemical and kinetic factors operating on the quantitative metal ion extraction were studied and optimized. It was found that quantitative metal ion sorption was possible in the pH range of 5.0-7.0, 3.0-4.0, 5.0, and 6.0-7.0 for U(VI), Th(IV), Pb(II), and Cd(II), respectively. The developed resin showed faster exchange rates and a high metal exchange capacity value of 202, 185, 179, and 86 mg g(-1) for U(VI), Th(IV), Pb(II), and Cd(II), respectively. The newly synthesized resin possesses improved metal extraction efficiency as revealed by the flow rate and kinetic studies, with complete metal ion saturation effective in < 15 min, with a t(1/2) value of <5 min, for all the metal ions of interest. The ion-selective behavior of developed resin was tested using various interfering electrolyte and metal ion species and was found to have greater tolerance toward these matrix species in the process of quantitative trace metal ion recovery down to the parts per billion ppb level. A high preconcentration factor value of 400 was achieved for U(VI), Th(IV), and Cd(II), respectively, and 500 in the case of Pb(II). The developed method was tested on its metal preconcentration ability, using synthetic and real samples. The system showed reproducibility and reliability in analytical data, with an rsd value of <4.1% on triplicate measurements.