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This work aimed to investigate the influence of modified titanium(IV) oxide by different nanosized particles on photocatalytic capacity to decompose the chosen organic pollutant under simulated sunlight. For that purpose, rutile-phased titanium(IV) oxide (r-TiO2) was decorated with iron vanadate (FeVO4/r-TiO2) and vanadium-substituted goethite (Fe1-xVxOOH/r-TiO2). The obtained composites were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X ray powder diffraction, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy – attenuated total reflec-tance and ultraviolet–visible diffuse reflectance spectroscopy techniques. Both synthesized photocatalysts showed higher photoactivity than the base r-TiO2 for the degradation of the target contaminant - thiophanate-methyl (2.5 h vs. 5 h). During the tests, parameters like the irradiation time, catalysts amount, and pesticide concentration were systematically investigated. Furthermore, photocatalysts were applied in multicycle degradation tests for examining their effectiveness during exploitation time. Monitoring of the removal rate was performed both by UV/visible spectrometry and high-performance liquid chromatography (HPLC). In order to prove completion of fungicide degradation chemical oxygen demand was measured in the course of the photocatalytic experiment. The final concentration of the observed contaminant in treated samples was under the prescribed legislative level. The fabricated materials displayed great reliability, durability and photocatalytic activity repre-senting good potentials for implementing this process in real wastewater treatment plants.

This paper deals with fractionation of the essential oil from juniper (Juniperus communis L.) berries by hydrodistillation (HD) and simultaneous hydrodistillation and rectification (SHDR) at atmospheric pressure. A rectification column was filled with the NORMAG packing A type and had 36 theoretical stages. In the present study, higher essential oil yield was obtained by HD (1.34 mass %) than by SHDR (1.17 mass %). However, mass fraction distributions of monoterpene hydrocarbons (MHs), oxygenated monoterpenes (OMs) and sesquiterpene hydrocarbons (SHs), observed for the two separation methods, differed from each other. In the SHDR process increased contents of high volatile components (predominantly MHs) were obtained in the initial fractions as well as increased contents of low volatile components (dominantly SHs) in the last fractions. Also, this method increased the separation degree of OMs. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 033007 and Grant no. 173021]

Essential oils are aromatic, volatile, complex mixtures of various compounds, mainly hydrocarbons (monoterpene and sesquiterpene) and some oxygenated hydrocarbons. Juniper berry essential oil has wide application and high commercial value due to its considerable antimicrobial activities. It is used in medicine, food, cosmetic and pharmaceutical industry and veterinary medicine. Generally, it is obtained by hydrodistillation, technique for the extraction of substances which do not mix or mix very poorly with water and are unstable at their boiling temperatures. It provides high quality of essential oil and also represents a relatively simple, safe and environmentally friendly process. The variations in the chemical composition of the essential oil obtained from juniper berries at various distillation rates (3, 6 and 8 ml/min) and various mass ratio juniper berries−water (hydromodules - 1:3, 1:4 and 1:5) are presented in this paper. It is important to emphasize that the variations made influence only in quantitative (mass %), but not in qualitative chemical composition (no differences, same 58 components were detected in all experiments). To reflect those effects, only 23 identified components with the content higher than 0.5 mass % were selected, constituted 95−96 mass % of the essential oils. The major constituents of the essential oils were monoterpenes (67.39−71.00 mass %), followed by sesquiterpenes (21.64−24.54 mass %), while the oxygenated monoterpene (1.54−2.42 mas. %) and oxygenated sesquiterpenes (0.89−1.46 mass %) were much less present. According to volatility, the high volatile (boiling point 153−167ºC) components are the main constituents of the essential oils (61.69−63.81 mass %), followed by the low volatile (boiling point 252−288oC) components (22.57−26.04 mass %), and the least present medium volatile (boiling point 173−212ºC) components (7.24−9.61 mass %). The variations in the mass content of the essential oil at various distillation rates showed clear general trends for all hydromodules (with exceptions at some components). With the increasing of distillation rate, mass % of high and medium volatile components decreased, while mass % of low volatile components increased. This is caused by higher extraction of low volatile components at high distillation rate, which resulted the increasing of their mass %. The variations in the mass composition of the essential oil at various hydromodules showed less expressive trends for all distillation rates. That means it has much less influence on the mass composition than the variation of distillation rate. Therefore, experiments at various distillation rates should be continued in combination with the fractionation of the essential oil by simultaneous hydrodistillation and rectification, including the effects of preparation procedures of juniper berries and defining of optimal energy consumption, i.e. optimal time period of hydrodistillation.

The present work deals with modeling the kinetics of essential oils extraction from plant materials by water and steam distillation. The experimental data were obtained by studying the hydrodistillation kinetics of essential oil from juniper berries. The literature data on the kinetics of essential oils hydrodistillation from different plant materials were also included into the modeling. A physical model based on simultaneous washing and diffusion of essential oil from plant materials were developed to describe the kinetics of essential oils hydrodistillation, and two other simpler models were derived from this physical model assuming either instantaneous washing followed by diffusion or diffusion with no washing (i.e. the first-order kinetics). The main goal was to compare these models and suggest the optimum ones for water and steam distillation and for different plant materials. All three models described well the experimental kinetic data on water distillation irrespective of the type of distillation equipment and its scale, the type of plant materials and the operational conditions. The most applicable one is the model involving simultaneous washing and diffusion of the essential oil. However, this model was generally inapplicable for steam distillation of essential oils, except for juniper berries. For this hydrodistillation technique, the pseudo first-order model was shown to be the best one. In a few cases, a variation of the essential oil yield with time was observed to be sigmoidal and was modeled by the Boltzmann sigmoid function.