RESUMEN
The article presents the results of the synthesis and research of a new biodegradable hybrid nanosized polymer-inorganic system possessing the double nature of heavy metal ions extraction from solutions. Firstly, the sorption of metal ions takes place by the ion-exchange properties of porous manganese oxide and, secondly, due to specific interaction and chelating with functional groups of polysaccharides in terms of nanochitin (ChNC). The synthesis is based on the colloid-chemical processes of interaction between polysaccharide and manganese oxide nanosized particles. Using the mathematical model of the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory, it has been shown that this interaction occurs due to the formation of hydrogen bonds and electrostatic interactions of oppositely charged particles. Hybrid sorbents were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron and Atomic force microscopy. The highest value of sorption capacity for hybrid materials was obtained for Ni2+ extraction and reached 114.0 ± 1.1 mg/g. It was shown that biodegradation of hybrid sorbents increases with the concentration of manganese oxide nanoparticles and almost complete degradation of the organic part can be performed within 6 days. The obtained biodegradable sorbents were designed to address ecological problems connected with the pollution of natural waters by toxic metallic ions.
RESUMEN
The hydrosols of chitin nanocrystals (ChN) are promising as modifiers of properties, drug delivery systems, and media. The purpose of this work is to clarify the mechanisms for regulating processes of stability and structure formation occurring in the ChN hydrosols under the influence of varying ionic strength. ChN were isolated from the crab shell; ChN hydrosols are obtained with different concentrations of the dispersed phase. The structure and morphology of the particles was studied by atomic force microscopy and X-ray diffraction. Hydrosols were studied by rotational viscometry, dynamic light scattering, and photometry in the presence of KCl with concentration up to 200mM. The experimental results of finding the rapid coagulation threshold are compared with calculated ones performed with the use of the modified DLVO theory. It is established that in the range of electrolyte concentrations 30â¼75mM, the optical and rheological properties of the ChN hydrosols undergo crucial changes. At an electrolyte concentration of 20â¼150mM, particles coagulate at a secondary potential minimum; the parallel orientation of the particles is energetically more advantageous. In systems with a higher concentration of electrolyte, there is no potential barrier; rapid barrier-free coagulation is observed, with the formation of stronger coagulation contacts and the formation of stable gels.