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INFLUENCE OF UV-IRRADIATION ON MOLECULAR WEIGHT OF CHITOSAN

100%
Sionkowska A., Płanecka A., Lewandowska K., Kaczmarek B., Szarszewska P.
Progress on Chemistry and Application of Chitin and its Derivatives
|
2013
|
vol. 18
|
issue 18
21-28
EN
In the present paper the results regarding the influence of UV-irradiation with 254 nm wavelength on the molecular weight of chitosan are presented. The concentration of chitosan solution was 0.5%(w/w) in 0.1 M acetic acid. The degree of deacetylation, determined by potentiometric titration in an acidic solution by alkaline, was 81%. Viscosity-average molecular weight of chitosan was determined using an Ubbelohde capillary viscometer. Mark–Houwink equation for the calculation of molecular weight was applied. The results showed that the viscosityaverage molecular weight of chitosan was decreasing with increasing time of exposure to UV-irradiation. Spectroscopic analysis of UV-Vis and FTIR confirmed the photodegradation processes of chitosan. The increasing absorbance in UV-Vis spectra indicated the formation of new chromophoric groups after UV-irradiation of chitosan. Microscopic studies showed changes on the surface of the irradiated films of chitosan and decrease of the surface roughness.
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Activity of phthalocyanine-sensitized TiO2-anatase in photooxidation of sulfite ions

88%
Galbas M., Banaszczyk A., Dyrda G., Szczegot K., Słota R.
Polish Journal of Chemical Technology
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2015
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vol. 17
|
issue 2
64-69
EN
Hybrid catalysts based on the TiO2 matrix impregnated with Nd, Eu and Yb diphthalocyanines proved effective in oxidation of sulfite ions under irradiation with light from the UV-visible range. Micro- and nano-crystalline anatase powders were used in preparation of the photocatalysts, which were applied in the form of a suspension in the water phase. The reaction yield was found to depend on the phthalocyanine sensitizer used and the conditions of TiO2 impregnation. The best results were obtained when micro-anatase impregnated with Yb-diphthalocyanine was used.
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