In the recent past it was taken into account that the level of protection of metal should be as high as possible, and very little about how these, usually very toxic, substances act on the environment and human health. With the development of industry and increase in industrial production at the global level it has become a very serious environmental and health problem. In the last ten years, as well as in nowadays, many researchers in the world are working on finding and using new substances which have good protective properties that they do not pollute the environment and that are not harmful to human health, i.e. so called "green inhibitors". According to needs we have, in our research, explored the possibility of use of vitamins B, C and sage extracts as possible inhibitors of corrosion of steel and copper in 3% solution of NaCl and 4 % solution of hydrochloric acid. For this purpose two different electrochemical methods were used, i.e. classical potentiodynamic measurement and electrochemical impedance spectroscopy (EIS). In addition In continuation the inhibitory effect of vitamins and sage extract on the corrosion process of technical copper and steel samples was studied by gravimetric method for a period of 2, 4 and 6 hours. All samples were subjected to chemical preparation, and then tests of corrosion rate in uninhibited and inhibited solutions were conducted. For copper protection in a 4% HCl vitamin C, for working conditions, demonstrates better results than in NaCl solution. The highest level of protection in 4% HCl solution was achieved at concentration of vitamin C of 1.5 g/dm3 in the time interval of 4h where z = 71.62%. In 3% NaCl solution vitamin B, as an inhibitor, shows somewhat better protective properties than in 4% HCl solution. The protection factor was in the interval from 47.77 to 64.60%. For steel protection, vitamin C does not show good protective properties, while vitamin B showed the best protective properties in 4% HCl solution for all used concentrations for a period of 6h (z = 77.27 to 86.03%).. These results are recommended vitamin B as a potential inhibitor in HCl solutions. The highest level of protection in 3% NaCl solution at sage extract concentration of 1.5 g/dm3 over a period of 6h was z = 97.5%. These results recommend sage as possible corrosion inhibitor in 4% HCl and 3% NaCl solutions. Previous studies of the application of various vitamins and extracts of different plants as corrosion inhibitors have shown that, under proper conditions, these substances can adequately replace the classical inhibitors and in the future it is expected that "green inhibitors" will be used, without pollution of the environment and without any harmful effects on health of living beings.
B.04 Guest lecture
COBISS.SI-ID: 18949398In recent years, membrane technology has been widely used in wastewater treatment and water purification. Membrane technology is simple to run and produces very high quality water for human consumptions and industrial purposes. One of the promising technologies for water and wastewater treatment is the application of forward osmosis (FO). This technology has several advantages over the existing technologies, such as, spontaneity of mass transport that eliminates the need for operation with high hydraulic pressure. Hence, it provides an opportunity for saving energy. However, there are many limitations that still need to be addressed. One of the current challenges is the preparation of second generation membrane. The biomimetic membranes (aquaporin) are such a recent development in FO process that improves the membrane separation and flux. The present studies review the effectiveness of aquaporin FO membranes for different applications.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 19081238For many biomedical applications, the control of morphological structure, total porosity, and pore size distribution of PHEMA-based materials is of paramount significance. Larger macropores, in the order of magnitude of a few tens of micrometers, may be achieved by the use of emulsion templating, such as high internal phase emulsions (HIPEs). With this approach, an emulsion with a high share of droplet phase (tipically over 75 vol %) and monomers in the continuous phase, can be prepared. Such emulsions are stabilized by surfactants and result after curing in highly porous polymers (polyHIPEs) with open cellular porous morphology.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 187251423-(3,4-Dihydroxyphenyl)-2-propenoic acid (Caffeic acid-Caf) and (E)-3-(4-hydroxy-3-methoxy-phenyl)prop-2-enoic acid (Ferulic acid-Fer) can exist in trans- and cis-forms, both of which can be found in plants. Trans-forms of Caf and Fer are naturally predominant isomers. However, the study proved that the mentioned trans-isomers are unstable and sensitive to many different factors such as high temperatures, exposure to UV radiation or oxygen from air, as well as metal ions, and under these conditions, isomerization to their cis-forms occured. The described study proved that after trimethylsilyl (TMS) derivatization gas chromatography coupled to mass spectrometry (GC-MS) allows good separation and quantitative determination of geometric cis- and trans-isomers of selected compounds. It was also confirmed that the isomerization is minimal in the first 24h aging of the solution for the compounds stored at room temperature and in refrigerate. On the other hand, during this time the Caf exposed to the sunlight isomerized 24% and Fer 25%. At the end of the study (after one month of aging in THF at room temperature), the content of trans-Caf decreased to about 67% and the content of trans-Fer to about 63%.
B.06 Other
COBISS.SI-ID: 18975510The thermal decomposition of the complex (ABT)3[Eu(Pydc)3]5H2O exhibits three stages of decomposition within the ranges 30–160 °C (DTGmax = 115 °C), 160–400 °C (DTGmax = 270 °C), 400–600 °C (DTGmax = 475 °C), with weight losses of about 7.50 %, 45.5 % and 15.9 %, respectively. The first stage corresponds to the loss of the 5 moles of crystal water molecules, with a weight loss (Δmmeas = 7.1%), which is in good agreement with the value calculated for the release of the water from the coordination sphere (Δmcalc = 7.5 %). During the second stage, above 400 °C, the compound started to decompose, which corresponds to the weight loss of the (ABTH)+(PydcH)−. The weight loss in the last step (oxygen atmosphere) can be used to calculate the final product. The total measured weight loss is about 86.4 %, which is in good agreement with the values calculated by taking Eu2O3 (Δmcalc = 85.3 %) as the final product, which was characterized by X−ray powder diffraction. Similar behavior was observed for (ABT)3[Tb(Pydc)3]5H2O).
B.03 Paper at an international scientific conference
COBISS.SI-ID: 18934806