Место издания:Samarkand State University named after Sharof Rashidov Samarkand
Первая страница:63
Последняя страница:63
Номер статьи:P-15
Аннотация:Recently, the problem of microplastics (MPs) – polymer particles 5 mm in size and less, which are divided into primary and secondary MPs, has become relevant. The primary MPs are specially prepared polymeric pellets and beads, which are used in medicine, cosmetics, household chemicals. The secondary MPs are formed as a result of the degradation of polymer products or wastes and particles of the primary MPs under different environmental conditions. Synthetic microspheres are often used when studying biological and physico-chemical properties of MPs. Such model particles with a dense core and a smooth surface with functional groups on it adequately imitate the properties of the initial or primary MPs but cannot reproduce the structure of the aged or secondary MPs. The real MPs undergo aging under the influence of the environment. As a result, their aggregate stability and porosity change, sorption capacity to different substances including toxic ones (heavy metals, cationic polymers – polycations, antibiotics, etc.) increases. Subsequent contact of these particles with different organisms can cause various negative consequences. In this work, the interaction of polycations with two types of model MPs: anionic polystyrene microspheres (PMs) with a size of 380 nm and anionic particles of microgel (MGs) with a size of 570 nm (copolymer of acrylic acid, N-isopropylacrylamide and a crosslinker) has been studied. The first type reproduced the structure of dense particles of initial MPs, the second type of particles, which are loose and permeable for the solvent and dissolved substances, imitated the structure of aged MPs. The interaction of model MPs with polycations was accompanied by neutralization of particles charge and aggregation of resulting complexes. When adding free MGs to the precipitate of MG-polycation complex polycations retained their mobility and redistributed between all MG particles in the system, that resulted in dissolution of the complex sediment and formation of the small negative MG−polycation complex particles in solution. Whereas no noticeable changes were observed in the system involving PMs and the precipitate preserved. The results obtained indicate that the structure of MP particles influences their interaction with polycations and subsequent behavior of resulting complexes. MGs (model of aged MPs) are able to exchange of polycation macromolecules that promotes the spread of toxins in the environment. The role of MPs as a vector of toxic substances should be taken into account when discussing the environmental and biological impact.
