This work describes a two-stage technique of X-ray fluorescence (XRF) analysis of rare earth niobates. A comparison between the two approaches revealed that the Fundamental Parameters Method (FPM) can be employed for a rapid preliminary assessment of the composition of the resulting material and the construction of calibration curves can be used to determine the contents of the major elements with precision. The results of the relative standard deviation (RSD) for FPM were no more than 7%, while the approach to construct calibration curves had an RSD of no more than 1%. Calibration samples were prepared using the same synthesis method as the study samples to construct the calibration curves. The possibility of constructing calibration dependencies using mixtures of oxides was assessed, but this approach could not provide the desired accuracy. The obtained results have been shown to have a good correlation with inductively coupled plasma optical emission spectrometry. The developed technique enables the determination of the major components in niobates containing two and three rare earth elements, which are used as optical materials and medium-entropy ceramics.

As the object of investigation in the present study, reactive distillation based on the transesterification of isopropyl acetate (IPAc) and 2,2,3,3,4,4,4-heptafluorobutanol (HFBol) under acidic conditions is addressed. This process aims to obtain 2,2,3,3,4,4,4-heptafluorobutyl acetate (HFBAc), which is used in the production of non-aqueous electrolytes, ethyllithium sulphate, charge retention medium, ultraviolet light-absorbing oligomers, etc. Through a combination of NMR spectroscopy and GC-MS, it was determined that during the process, the following were primarily formed in the system: target HFBAc and the by-product, isopropanol. The following side-products were identified: di-isopropyl ether, acetic acid, water, and 2,2,3,3,4,4,4-heptafluorobutyl isopropyl ether (HFB-IPEth). No bis(1H,1H-heptafluorobutyl) ether or acetic anhydride were identified in the system. For HFBol, HFBAc and HFB-IPEth the ¹H, ¹⁹F and ¹³C{¹⁹F}), ¹⁹F-¹⁹F COSY NMR, and mass spectra were reported in this study.

The presence of fluoroquinolone antibiotics in aquatic environments raises serious ecological concerns due to their toxicity and ability to promote antibiotic resistance development. This study investigates a combined approach to water purification that integrates hydrodynamic cavitation with plasma discharge for the degradation of enrofloxacin in aqueous solutions. The influence of electrical pulse power (1.5 and 3.0 kW) and the number of treatment cycles (1–2) was evaluated at initial antibiotic concentrations of 10 and 100 mg/L. At lower power during two treatment cycles, the degree of antibiotic degradation has reached 69.2%. Additionally, a prolonged effect of the treatment was identified, caused by the oxidation of intermediate decomposition products by reactive oxygen species generated within the system. The most pronounced effect has been observed at an enrofloxacin concentration of 10 mg/L. The obtained results confirm the high efficiency and practical potential of this hybrid technology for the removal of antibiotics from water treatment systems.