Residual heavy metals in industrial chitosan: State of distributionстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 4 февраля 2021 г.
Аннотация:A series of industrial chitosans were analyzed on the presence of residual heavy metals. For the first time, opticalmicroscopy data showed that chitosan solution retained a huge number of insoluble microparticles while transmittanceelectron microscopy revealed that insoluble fibrous microparticles were incrusted by crystalline nanoparticleswith the sizes 5–50 nm. A series of filters used for chitosan solution filtration was analyzed on thepresence of retained heavy metal and other residuals by scanning electron microscopy with energy dispersiveX-ray spectroscopy (SEM-EDXS) and mass-spectrometry with inductively coupled plasma (ICP-MS) methods.The SEM-EDXS analysis revealed the presence of Fe residuals together with Si, Al, N and S in the particlesfound on the filters. ICP-MS analysis found the presence of heavymetals (mainly Fe, Cr and Ni) both on the filtersurfaces and in the effluent chitosan solution passed though the filters.This study draws attention to the necessity of a careful selection of industrially manufactured chitosan in order toavoid hidden undesirable effects of chitosan on pharmaceuticals and biomaterials and gives awarning of inapplicabilityof a stainless-steel made apparatus as a reactor susceptible to caustic soda corrosion for chitindeacetylation and production of medical and food grade chitosan.