부산대학교 도서관

Using an example of the adsorption of Ag(I), Au(III), and Pd(II) ions from aqueous solutions, we studied the dependence of the adsorption capabilities of MNP@CNT magnetic adsorbents on the ratio of their components: magnetite nanoparticles (MNPs) and carbon nanotubes (CNTs) synthesized by the catalytic pyrolysis of ethanol vapors using various catalysts of the iron group. The adsorption capacity of all types of composites increases with the concentration of CNTs in them relative to MNPs. The component ratio of 10 : 1 was optimal for the composites with all CNTs obtained with various catalysts and having different morphologies. At this ratio, the composite has the maximum adsorption capacity for the studied ions, which is 6.5, 6.1, and 5.5 mg/g for Ag(I), Au(III), and Pd(II), respectively, and sufficient magnetization for phase separation in a magnetic field. The modification of CNTs with magnetic nanoparticles enables using the resulting composite in both batch and dynamic versions of solid-phase extraction; previously, individual CNTs obtained with cobalt and iron catalysts did not demonstrate proper results. In the dynamic mode, large volumes of test solutions can be used; higher preconcentration factors are achieved compared to the batch mode; lower limits of element determination are obtained after the evaporation of the eluates from the graphite powder. For all types of composites, a comparative metrological evaluation of the results of element determination by arc atomic emission spectroscopy was performed. The obtained limits of determination for elements are n x 10.sup.-7 wt % (K.sub.preconc = 200).
Author(s): S. S. Grazhulene [sup.1], N. I. Zolotareva [sup.1], A. N. Redkin [sup.1] Author Affiliations: (1) grid.425037.7, 0000 0004 0638 3022, Institute of Microelectronics Technology and High-Purity Materials, Russian Academy [...]