In this work, chitosan-TiO2 nanocomposites (NСs CS-TiO2) were developed for the photocatalytic degradation of some representatives of polycyclic aromatic hydrocarbons (PAHs). TiO2 nanoparticles (NPs) were synthesized by laser ablation method and their sizes were determined by dynamic laser light scattering (DLLS). Anthracene and pyrene in micellar solution were used as representatives of PAHs. The effect of TiO2 in the composition of prepared nanocomposites on the photodegradation of PAHs in model environments under UV irradiation was studied. The method of solid-phase luminescence (SPL) was used to estimate the decrease in PAHs concentrations. Based on the results of the studies carried out, pseudo-first order photodegradation kinetics were plotted. The efficiency of using the nanocomposites for the photocatalytic degradation of anthracene and pyrene was proved.

No abstract

The article describes the results of finite-difference time-domain (FDTD) mathematical modeling of electric field strength distribution near the gold laser-induced periodic surface structures (LIPSS). Both theoretical and experimental results have been described for two fabricated morphologies: round «hill-like» and grating structures. The structures were fabricated by using a femtosecond Yb-fiber laser with a wavelength of λ=1032 nm, pulse duration τ=280 fs, and repetition rate υ=25 kHz. Morphological properties of the surfaces have been investigated by means of scanning electron microscopy (SEM). The plasmonic activity was analyzed by means of the surface-enhanced Raman spectroscopy (SERS) technique. FDTD-calculated electric field values were converted into the electromagnetic field enhancement coefficient and the theoretical SERS intensity. The prospects of the theoretical approach for LIPSS to evaluate optimal field amplification and light scattering parameters has been shown. The presented approach could be applied as a basis for performing the methods of controlled synthesis for LIPPS.

The preparation method of modified chitosan films for adsorption of pyrene from solution is described. Solid-phase luminescence of samples was studied, degree of extraction and index of polarity of microenvironment of pyrene molecules was determined. It has been proven possible to carry out luminescent analysis of substances for pyrene content using made films. The observed results demonstrate an ability for the using method of solid-phase luminescence (SPL) to increase the range of optical transparency and avoid pre-extraction and concentration of the test samples.

No abstract