The aim of the work is to study the effectiveness of a molecular imprinting technique application for the creation of highly selective macromolecular sorbents for selective sorption of light and heavy rare-earth metals (for example, samarium and gadolinium, respectively) with subsequent separation from each other. These sorbents seem to be promising due to the fact that only the target rare-earth metal will be sorbed owing to the fact that complementary cavities are formed during the synthesis of molecularly imprinted polymers. In other words, the advantage of the proposed macromolecules is the absence of accompanying sorption of metals with close chemical properties. Two types of molecularly imprinted polymers (MIP) were synthetized based on methacrylic acid (MAA) and 4-vinylpyridine (4VP) functional monomers. The sorption properties (extraction degree, exchange capacity) of the MIPs were studied. The impact of template removal cycle count (from 20 to 35) on the sorption effectivity was studied. Laboratory experiments on selective sorption and separation of samarium and gadolinium from a model solution were carried out.

This present study is targeted at the complex investigation of the behavior of interpolymer systems based on acidic rarely crosslinked polymeric hydrogels (polyacrylic acid hydrogel (hPAA); polymethacrylic acid hydrogel (hPMAA)) and basic rarely crosslinked polymeric hydrogels (poly-4-vinylpyridine hydrogel (hP4VP), specifically the poly-2-methyl-5-vinylpyridine hydrogel (hP2M5VP)) either in an aqueous medium or lanthanum nitrate solution. We found that the transition of the polymeric hydrogels in the developed interpolymer systems (hPAA-hP4VP, hPMAA-hP4VP, hPAA-hP2M5VP, and hPMAA-hP2M5VP) into highly ionized states leads to significant changes in electrochemical, conformational, and sorption properties of the initial macromolecules. The subsequent mutual activation effect demonstrates strong swelling of both hydrogels in the systems. The sorption efficiency of lanthanum by the interpolymer systems is 94.51% (33%hPAA:67%hP4VP), 90.80% (17%hPMAA-83%hP4VP), 91.55% (67%hPAA:33%hP2M5VP), and 90.10% (50%hPMAA:50%hP2M5VP). An advantage of the interpolymer systems (compared to individual polymeric hydrogels) is the strong growth of their sorption properties (up to 35%) due to high ionization states. Interpolymer systems can be considered new-generation sorbents for further application in the industry for highly effective sorption of rare earth metals.

A new approach to the production of commercial products used in aromatherapy and household aromatizing agents based on induction heating of plant raw materials and the use of hydrophilic polymer hydrogels is proposed. It is shown that obtaining highly purified essential oils is neither technologically nor economically justified from the point of view of their use in aromatherapy. The proposed approach makes it possible to obtain products for aromatherapy with minimal processing of raw materials and low production costs. The main end product is a polymer hydrogel saturated with a liquid phase formed during induction heating of a mixture of a plant component with metal inclusions. Such a product, among other things, allows the implementation of electronic aromatherapy systems and household aromatizing agents, in which the generation of aroma oils is also provided by induction heating. In the operation of such systems, the basic property of thermosensitive hydrogels is used – a shift in the hydrophobic-hydrophilic balance with temperature variations, which makes it possible to exclude parasitic evaporation of volatile components. Specific technical solutions that implement this approach are proposed.