SORPTION OF APOLAR LIQUIDS BY NATURAL HIGH MOLECULAR COMPOUNDS

Abstract

The modern technologies of the adsorption processes are searching of the new, ecologically friendly adsorbents as natural polymers – chitin and chitosan. Chitin and chitosan adsorbents have high adsorption ability in relation to mineral oils, dyes, alcohols, phenols and heavy metals. The basic natural sources of chitin are the shells of crustacean and the biomass of fungus` mycelium. Chitin provides the mechanical strength of the structure without rigid bonds between microfibrilles, that allows to keep the certain elasticity of a cellular wall. The submitted researches are devoted to studying adsorption activity of chitosan and chitin received from the shells of crustacean in relation to of organic polutants. It was shown that the use of chitin and chitosan polymers of natural origin as sorbents is a worthy alternative to synthetic sorbents. Natural sorbents have advantages due to environmental friendliness, safety and biodegradability. It has been experimentally proven that the investigated natural polymers absorb organic pollutants with an efficiency of up to 98%. The nature of the polymer and the method of its introduction affect the effectiveness of the sorption process. Sorption can be described using the Langmuir and Freundlich sorption equations. In order to clarify the sorption mechanism, the temperature dependence of the process was studied. In all cases, the sorption of vaseline oil decreases with increasing temperature, which suggests a physical mechanism of sorption. Sorption occurs due to dispersion interaction. Hydrophobic interactions between molecules of organic substances and non-polar regions of chitosan macromolecules make a certain contribution to the mechanism of sorption of the studied substances. The effective sorption capacity of chitosan is explained not only by its physical and chemical properties, the developed structure of micropores, but also by the method of adding the sorbent. Apolar liquids are sorbed due to hydrophobic interaction, chitosan forms hydrogen bonds that can bind polar components in the composition. The high sorption activity of chitosan in relation to organic pollutants, surface-active substances, heavy metals, dyes, its renewability and ability to biological decomposition allow it to be considered a sufficiently effective and practically universal sorbent.