1 Phenomenon of the long-range effect of poly(methacrylic acid) hydrogelpoly(4-vinylpyridine) hydrogel (gPMAA-gP4VP intergel system) оn erbium ions sorption was studied. It was established that the structure of the basic hydrogel had a significant impact on the self-organization of the PMAA hydrogel. The mutual activation of hydrogels was investigated in an aqueous medium. Dependencies of swelling coefficient, specific electric conductivity and pH of aqueous solutions were determined. Individual PMAA and P4VP hydrogels showed the erbium ions extraction degree of about 44 % and 17 %, respectively. At the ratios 5:1 (83 % of gPMAA-17 % gP4VP) and 4:2 (67 % gMPAA-33 % gP4VP), 56 % and 53 % of erbium ions were recovered, respectively. After 48 h the PMAA and P4VP hydrogels had the polymer chain binding degree of 70 %. The obtained results point to the evidence that at these ratios there are significant changes in electrochemical and conformational degrees of initial macromolecules in gPMAA-gP4VP intergel system.
Abstract. Electrochemical properties of intergel system polyacrylic acid (gPAA) and poly-4-vinylpyridine hydrogels (gP4VP) and conformational properties of initial hydrogels were studied depending on hydrogels initial state. Maximum activation area is: for dry hydrogelsgPAA:gP4VP ratios 5:1 and 1:5, for swollen -ratios 5:1, 2:4 and 1:5.
Abstract.1 Sorption ability of intergel system polymethacrylic acid hydrogel (gPMAA) -poly-4-vinylpyridine hydrogel (gP4VP) in relation to lanthanum ions is studied. Hydrogels mutual activation in an aqueous medium, particularly dependencies of swelling coefficient, specific electric conductivity and pH of water solutions are studied. Maximum activation of hydrogels occurs at gPMAA:gP4VP molar ratio 3:3. Maximum total binding degree of polymer chain in the intergel system is observed at the ratio gPMAA:gP4VP = 1:5. It has the value of 73.13 %, which is much higher than at initial hydrogels: gPMAA binding degree is 55.17 %, gP4VP -55.00 %. The obtained results point to the fact that at this ratio there are significant changes of electrochemical, conformational and sorption degrees of initial macromolecules in intergel system.
Features of sorption of rare-earth metals of cerium group by intergel systems based on polyacrylic acid, polymethacrylic acid and poly-4-vinylpyridine hydrogelsThe work is devoted to study of sorption process of cerium and neodymium ions by individual hydrogels of polyacrylic acid (hPAA), polymethacrylic acid (hPMAA), poly-4-vinylpyridine (hP4VP) and intergel systems on their bases. Obtained results show that sorption properties (sorption degree, polymer chain binding degree, effective dynamic exchange capacity) of individual hydrogels of PAA, PMAA, P4VP are not sufficiently high: sorption degree is not high that 65 %; polymer chain binding degree is not high than 55 %; effective dynamic exchange capacity is not high than 4.5 mmol/g. Remote interaction of the polymer hydrogels in the intergel systems provides significant increase (over 30 %) of the sorption properties. Sorption degree increases up to 93.50 %; polymer chain binding degree increases up to 76.50 %; effective dynamic exchange capacity grows to 6.16 mmol/g. Such strong increase is a consequence of the mutual activation of the initial polymers in the intergel systems during their remote interaction. Macromolecules undergo ionization with further unfolding of the polymer globe with formation of optimal conformation for sorption of low-molecular ions.
The goal of the present work is a comparative study of the effectiveness of the application of intergel systems and molecularly imprinted polymers for the selective sorption and separation of neodymium and scandium ions. The following physico-chemical methods of analysis were used in this study: colorimetry and atomic-emission spectroscopy. The functional polymers of polyacrylic acid (hPAA) and poly-4-vinylpyridine (hP4VP) in the intergel system undergo significant changes in the initial sorption properties. The remote interaction of the polymers in the intergel system hPAA–hP4VP provides mutual activation of these macromolecules, with subsequent transfer into a highly ionized state. The maximum sorption of neodymium and scandium ions is observed at molar ratios of 83%hPAA:17%hP4VP and 50%hPAA:50%hP4VP. Molecularly imprinted polymers MIP(Nd) and MIP(Sc) show good results in the sorption of Nd and Sc ions. Based on both these types of these macromolecular structures, principally new sorption methods have been developed. The method based on the application of the intergel system is cheaper and easier in application, but there is some accompanying sorption (about 10%) of another metal from the model solution during selective sorption and separation. Another method, based on the application of molecularly imprinted polymers, is more expensive and the sorption properties are higher, with the simultaneous sorption of the accompanying metal from the model solution.
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