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.

Many technological solutions contain valuable components as waste and can become an additional source of rare-earth elements to meet the needs of modern production. The development of technologies based on commercially available and cheap sorbents reveals the possibility for rare earth recovery from various solutions. This paper provides research on using a combination of KU-2-8 and AV-17-8 ion exchangers in different molar ratios for cerium ions sorption from its nitrate solution. The mutual activation of the ion exchangers in an aqueous medium provides their transformation into a highly ionized state by the conformational and electrochemical changes in properties during their remote interaction. The ion exchange dynamics of solutions were studied by the methods of electrical conductivity, pH measurements, and atomic emission analysis of the solutions. The research showed that the maximum activation of polymers was revealed within the molar ratio of KU-2-8:AV-17-8 equal to 3:3. In more detail, in comparison to AV-17-8, this interpolymer system showed an increase in the sorption degree by more than 1.5 times after 6 h of interaction. Moreover, compared with KU-2-8, the same interpolymer system showed an increase in the degree of cerium ions sorption by seven times after 24 h of interaction. As a result, the total cerium ions sorption degree after 48 h of sorption by individual KU-2-8 and AV-17-8 was 38% and 44%, respectively, whereas the cerium ions sorption degree by the same interpolymer system in the molar ratio 3:3 became 51%. An increase in the sorption degree of cerium ions by the interpolymer system in comparison with individual ion exchangers can be explained by the achievement of a high ionization degree of ion exchangers being activated in the interpolymer system by the remote interaction effect.

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.

Some technological solutions contain valuable components and can become an additional source of rare-earth elements to satisfy the current production demands. This research provides the study on using a combination of polyacrylic acid hydrogel (hPAA) and hydrogel of poly-4-vinylpyridine (hP4VP) in different molar ratios for praseodymium ions sorption from its nitrate solution. The mutual activation of the hydrogels in an aqueous medium provides their transformation into a highly ionized state by the conformational and electrochemical changes in properties during their remote interaction. The electrochemical properties of solutions were studied by the methods of electrical conductivity, and pH measurements of the solutions. The research showed that the maximum activation of hydrogels was revealed within the molar ratio of hPAA:hP4VP equal to 1:5. Moreover, the total praseodymium ions sorption degree after 24 hours of sorption by individual hPAA and hP4VP was 54 % and 47 %, respectively, whereas the praseodymium ions sorption degree by the hPAA–hP4VP intergel system in the molar ratio 1:5 became 62 %. A slight increase in the sorption degree of praseodymium ions by the intergel system in comparison with individual hydrogels can be explained by the achievement of a higher ionization degree of hydrogels being activated in the hPAA–hP4VP interpolymer system by the remote interaction effect.