The study of spectral and luminescent properties of humic acids and their impact on the photodegradation process of 2,6-bis(hydroxymethyl)-4-methylphenol

UV photolysis (KrCl excilamp, λrad ~ 222 nm) of aqueous humic acids (HAs) samples was carried out without and in the presence of 2,6-bis(hydroxymethyl)-4-methylphenol. The samples of HAs fractions were obtained from Aldrich Chemical Co and prepared from peat of Arkhangelsk region. The presence of Aldrich humic acid in the solution has a essential effect on the processes of phenolic compound photochemical degradation under the action of light from the excilamp.

SPECTRAL AND LUMINESCENT PROPERTIES OF CARBON QUANTUM DOTS FUNCTIONALIZED WITH N- AND S-CONTAINING GROUPS

In the presented work, carbon quantum dots were obtained by microwave synthesis based on citric acid and Lcysteine. The resulting particles were characterized by electron and probe microscopy, dynamic light scattering and Fourier transform infrared spectroscopy. The spectral and luminescent properties were investigated for the initial solution of carbon quantum dots, as well as solutions obtained as a result of dialysis of the synthesized product. It is shown that all samples exhibit the same optical properties. At the same time, the measurement of quantum yields showed that carbon dots that have passed through the dialysis membrane have the best fluorescent ability.

THE INFLUENCE OF SUPERPARAMAGNETIC Fe3O4 NANOPARTICLES ON SPECTRAL AND LUMINESCENT PROPERTIES OF MESOSTRUCTURED SiO2/P123/Rh6G/Fe3O4 FILMS FORMED IN STATIONARY MAGNETIC FIELDS

The effect of superparamagnetic Fe3O4 nanoparticles (NPs) on the spectral luminescence properties of homogeneous optically transparent mesostructured silica films of SiO2/P123/Rh6G/Fe3O4, containing {P123 (Rh6G)} micelles consisting of Pluronic 123 with encapsulated Rh6G, and formed in stationary magnetic fields (MF) with an induction of less than 500 mT, was investigated. It was shown that, unlike SiO2/P123/Rh6G, the spectral and luminescent properties of SiO2/P123/Rh6G/Fe3O4 films depend on the MF used during their formation, and a gradual decrease in the band intensities in Rh6G spectra and quenching of luminescence with increasing of MF induction was observed. It is associated with a decrease in the monomer fraction and an increase in the fraction of non-luminescent Rh6G H-aggregates in micelles due to the interaction intensifying in the MF (formation of Fe3+ -O bonds) of superparamagnetic NPs with micelles {P123 (Rh6G)}, oriented in the MF, which leads to a gradual deformation of micelles and accumulation in them of H-aggregate. The dependences of the changes in the absorption bands intensity and fluorescence of the monomeric form of Rh6G in the spectra of the films on the changes in the magnetic induction of the MF are described by an exponential function, and the ratio of the fluorescence intensities of the SiO2/P123/Rh6G films to the fluorescence intensities of the SiO2/P123/Rh6G/Fe3O4 films linearly depends on the induction of MF, which they are able to "remember", which is manifested in the values of fluorescence intensities.