This article presents the influence of low frequency, high intensity ultrasonic irradiation on the characteristics (average size, polydispersity index) of ethyl cellulose nanocapsules encapsulating a photochromic dye. Photochromic nanocapsules were prepared by the emulsion-solvent evaporation method. The acoustic densities entering the system were systematically studied with respect to their abilities to modify and reduce the average sizes and polydispersity indexes of the nanocapsules. Scanning electron microscope, confocal laser microscope, and dynamic light scattering were utilised to characterise the structure, shape, size, and polydispersity of ethyl cellulose photochromic nanocapsules. We were able to tailor the size of the photochromic nanocapsules simply by varying the acoustic densities entering the system. At an acoustic density of 1.5?W/mL and 60?s of continuous irradiation, we were able to prepare an almost monodispersed population of the nanocapsules with an average size of 193?nm.
COBISS.SI-ID: 20690198
The synthesis of two new azobenzene dyes, namely CR-528 and CR-555, and their spectral properties in ethanol solution are described. The recognition of sulfur-containing analytes (2-mercaptoethanol (2-ME), sodium hydrosulfide (NaHS)), and biogenic amines (spermine, spermidine, ethanolamine) bestowed significant spectral changes with color changes from pink/purple to pale yellow/orange-yellow. The nitro acceptor group in the dicyanovinyl reactive dye contributes to higher sensitivity and lower detected analyte concentrations. The absorption maxima of both the dyes are at wavelengths compatible with low-cost light sources and detectors, making them excellent candidates for optical probes that are economic, simple to use, and do not require well-trained personnel.
COBISS.SI-ID: 21224214
In this work, mono-dispersed mercapto-functionalized silica (SiO2@SH) particles with a narrow particle size distribution of around 420 ± 10 nm were prepared by the sol–gel method for the adsorption of aqueous dissolved lead ions (Pb2+) from model wastewater. Dispersive X-ray Spectroscopy (EDXS) indicated strong signals of Si and S, implying successful mercapto (SH) functionalization of the silica (SiO2) surfaces. Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the occurrences of Si–O–Si and SH vibrations within the samples and, thus come to a conclusion about the formations of the mercapto-functionalized samples. The EXAFS/XANES (Extended X-ray Absorption Fine Structure/X-ray Absorption Near Edge Structure) analysis indicated complete Pb2+ complexation with two SH groups of the prepared SiO2@SH samples. The results for Pb2+ adsorptions from model wastewater showed affinity of around 55 % and the obtained value of the maximum amount of adsorbed Pb2+ ions on the surface of the SiO2@SH particles was 10.82 mg/g under studied conditions. Adsorptions results were fitted with the Langmuir and Freundlich isotherm models and the pseudo-first and pseudo-second kinetic models were evaluated.
COBISS.SI-ID: 20042774