Classical chemical sciences
The inhibition efficiency of sodium molybdate (SM) - Zn2+ system in controlling corrosion of carbon steel in seawater has been evaluated by weight-loss method. The formulation consisting of 250 ppm of SM and 75 ppm of Zn2+ has 80% IE. Influence of duration of immersion on the IE of SM – Zn2+ has also been evaluated. The mechanistic aspects of corrosion inhibition have been investigated by polarization study and AC impedance spectra. The protective film has been analyzed by FTIR, and luminescence spectra. The surface morphology and the roughness of the metal surface have been analyzed by atomic force microscopy. The protective film consists of Fe2+ – molybdate complex and Zn(OH)2. It is found to be UV - fluorescent.
Keywords: Carbon steel, sodium molybdate, synergistic effect, Atomic Force Microscopy (AFM), and sea water.
Ephedrine hydrochloride complexes of Ca(II), Sr(II) and Ba(II) non-transition metal ions were prepared. The compounds formed contains various amount of crystalline water (6, 8 and 4 for Ca, Sr and Ba, respectively) and were studied by IR, Raman and NMR methods. Electrolytic conductivity measurements showed that the complexes decompose into ionic particles in DMSO. The compounds show unusual high thermal stability.
Keywords: Ephedrine HCl, infrared spectra, Raman spectra, 1H–NMR.
Materials and environmental chemistry
Selenium is an essential trace element that has beneficial health effects in adequate concentration i.e. about 60 μg/day – in humans. Besides its antioxidant function selenium incorporated in seleno-aminoacids, selenomethionine and selenocysteine, as these aminoacids support anti-cancer and anti-aging effects. However ensuring the sufficient intake of this element may be limited in some countries, such as Hungary, because of the soil, which is deficient of selenium. In some literature it has been reported that oil seeds contain higher concentration of selenium, therefore they are potential selenium sources. The main aim of our work is to study and survey the role of these seeds in selenium intake into a human body. It has been pointed out that consuming these food products can minimize but not eliminate inadequate selenium intake, except that of brazil nut (Bertholletia excelsa) with its high (20 μg g-1) selenium-content.
Keywords: Selenium, Brazil nut, Trace element, ICP-MS, ICP-OES
Biochar is a highly porous solid substance, made of different biomass by pyrolysis. Conditions of pyrolysis as well materials used in it can substantially affect biochar properties. Samples with sufficient amount of stable carbon can be added into soil to be sequestered; high sorption surface of biochar could characterize it as a soil additive, able to immobilize risk elements in soil. Soil contamination by risk elements is a serious problem needs to be solved. There are available remediation methods, using plants to remove these elements from soil. Biomass produced during remediation has limited application and biochar production could be one option. Plants for our experiments were grown on contaminated soil of Příbram area. For the experiment they were used: meadow grass, wood mixture of poplar and willows twigs and finally maize. Biomass of these plants was used to prepare biochar. The effect of the type of biomass and the final temperature of pyrolysis on specific surface area and yield of biochar was studied in our experiments. Both temperature and plant material affected properties of biochar. While the final temperature increased, the specific surface area increased and the yield of biochar decreased. The highest surface area was found at biochar from wood mixture and the lowest one from meadow grass.
Keywords: biochar, soil, heavy metals, slow pyrolysis, biomass
The role of sediment and epipelon (organisms living on the surface of or in the fine-sized sediments) is significant in the life of aquatic ecosystems. The sediment is the place where the change of ion-transport occurs between the aquatic and solid phases, there are dynamic balance and buffer system between the sediment particles and the particles in the surrounding medium. As a result of the activity of the epipelon and the sediment organisms the metabolism pathways exist in the aquatic ecological systems that can indicate or influence on the habitat characteristics. Changes in the quality or quantity of epipelon indicate changes in water quality. From the point of view of nature conservation it can characterize a natural status or indicate the degree of disturbance (degradation). We measured the ETS (Electron Transport System) activity of the epipelon which gives the maximal intensity of the respiration metabolism. In the analysis of the epipelon the measuring of the ETS-activity can be used of the returns of taxonomic effects such as sublethal or physiologic damage caused by toxic poisons which cannot be discovered immediately and directly by taxonomic parameters, but the changing breath-activity can mark a changing state. ETS tests are suitable for indicating environmental stress.
Keywords: sediment, epipelon, ETS-activity, water, trophity
Biochemistry, molecular biology and biotechnology
Use of saline water for agricultural irrigation is leading towards salt accumulation in the root zone and consequent damage to crop production and soil fertility. Furthermore, it is known that increased root zone salinity can potentially increase plant trace element uptake. In this context, crop salt tolerance and growth response assessment is useful tool in managing salinity stress. A greenhouse pot experiment was set up to study the effects of irrigation water salinity on growth and element uptake of faba bean (Vicia faba L.). Three weeks old faba bean seedlings were transplanted into pots and automatically fertigated with a modified Hoagland nutrient solution. Two weeks after transplanting, treatment with four NaCl salinity concentrations in nutrient solution was applied as follows: NaCl0 – control (basic nutrient solution without added NaCl), NaCl35 (control + 35 mM NaCl), NaCl50 (control + 50 mM NaCl), NaCl65 (control + 65 mM NaCl). Increasing root zone salinity significantly enhanced Na and Cl accumulation in faba bean leaves. A decrease in Mo and K leaf content occurred most significantly at NaCl50 treatment, as well as an increase in Mn leaf content. NaCl treatments reduced P leaf content in regard to control but without significant difference amongst treatments. Results have shown that increased root zone salinity can affect certain faba bean leaf element accumulation, although trace element leaf content was not significantly altered. Hence, faba bean could be considered as rather salt tolerant horticultural crop.
Keywords: saline irrigation, element uptake, faba bean
Phytotoxicity effect of sodium selenite Se(IV) and selenate Se(VI) was followed on selected characteristics of garden pea (Pisum sativum), such as germination, growth, chlorophyll production, content of dry material and water in the seedlings. Laboratory experiments were established in the Petri dishes, which were treated with sodium selenate (Na2SeO4) and sodium selenite pentahydrate (Na2SeO3.5 H2O) on the selenium concentration levels 5.0; 20.0; 100.0; 300.0 and 500.0 mg Se/l. Phytotoxicity was tested by the tests of chronic phytotoxicity and the results obtained were evaluated as IC50 values (half maximal inhibitory concentration) by probit analysis. Treatment of seedlings with the solutions of Se(IV) and Se(VI) on the concentration levels 5 mg and 20 mg/l resulted in enhanced growth of shoots and roots, especially after application of Se(IV), where the growth exceeded control for about 70 %. The IC50 value was higher for the growth of shoots as well as for roots after application of Se(VI), the growth inhibition in early growth stages of garden pea can be observed only in the high selenium concentrations (over 200 mg Se/l). Se(IV) showed more significant inhibition of chlorophyll production in the shoots of peas seedlings than Se(VI). Lower concentrations of Se(IV) and Se(VI) (below 100 mg Se/l) did not show significant differences between the water contents, but the higher concentrations (300 mg Se(IV)/l and 500 mg Se(VI)/l) resulted in significant differences, more than 9-times higher in roots.
Keywords: Garden pea, Selenium phytotoxicity, Half maximal inhibitory concentration,Probit analysis
Data on mineral uptake of various scion-cultivar combinations demonstrated in the paper represent preliminary findings of a long term field experiment. The variety collection was established on immune sand soil in 2003. In the experimental field leaf samples were collected from 9 different rootstock and ’Cserszegi fűszeres’ scion cultivars (the same stocks) before vintage of 2011, along with that of own rooted stocks as control. In the samples 9 elements were analysed (K, Ca, Mg, Cu, P, B, Mn, Fe and Zn). Differences were found between mineral composition of leaf samples of rootstocks and ’Cserszegi fűszeres’ scion grafted on them. A consequently higher content of K, Mg, Mn, and Zn was found in scion, and P, Ca, B, Cu, Fe in rootstock leaf samples.
Keywords: grape rootstock, microelements intake, Cserszegi fűszeres, grape variety
Oral exposure of humans by excess amounts of arsenic and/or fluorine may cause disturbances of the nervous system. In the present study, such exposure was modelled in rats, with examination of general and behavioral endpoints. Seven weeks old adult male SPF Crl:WI BR Wistar rats (160±20 g, 4 groups of 12 rats each) were treated with sodium (meta)arsenite (10 mg/kg b.w.; As), sodium-fluoride (5 mg/kg b.w.; F) and their combinations (As+F) per os by gavage, 5 days in a week, once a day for 6 weeks. An untreated control group was also used (Control). General toxicological parameters (body weight gain, food and water consumption) were measured daily. Behavioral investigations (rota-rod and open field) were done in the 4th and 6th weeks of treatment. Weekly body weight gain was significantly reduced in the As (vs. F) and As+F (vs. Control and F) groups from the first week onwards. This difference was seen during the whole treatment period, and was more prominent from the second week on (As and As+F vs. Control and F). As, but not F, affected the relative weight of the liver, spleen and kidneys. Food and water consumption in the As and As+F groups was significantly reduced vs. Control and F, while a non-significant increase of water consumption was seen in group F. In the open field test, As and As+F caused significant decrease in rearing and ambulation, and increase in immobility and local activity, vs. Control and F. In the rota rod performance, no noteworthy change was observed. In the treatment scheme applied, significant effects on both general and behavioral endpoints by arsenic, but not by fluorine, were detected, which underlines the risk from environmental exposure.
Keywords: arsenic, fluoride, combined exposure, behavior, open field
The enzymatic and/or non-enzymatic methylation / hydroxymethylation of main trace elements renders a special, indispensable bridge between biological (organic) and inorganic world. These modified trace elements are potential formaldehyde (HCHO) generators and HCHO formed from them can participate in different characteristic interactions. On the basis of up-to-date biochemical results with HCHO it is supposed that trace elements as HCHO carriers transport HCHO molecules in dose-dependent level to different points of a given biological unit. On the basis of experiences with the time- and dose-dependent double immune response of plants to pathogens, a logical step was to extend it to the total Avogadro number range (in vivo conditions) in the case of trace elements as potential inducers as well. These new findings support that HCHO and its reaction products (mainly O3) as drastic molecules are responsible for the immunostimulating activity of trace elements as inducers. It is especially important that there are always four bioequivalent immunostimulating activity ranges in plants for the pretreatment with different doses of trace elements similar to organic compounds. It has to be noted that the trace elements as inducers actually don’t participate directly in the induction of the immunostimulating effect similar to organic inducers.
Keywords: formaldehyde, hormesis, inducer, pretreatment, quadruple immune response, trace elements
Industrial and engineering chemistry
A major issue with all flow batteries is the control of the imbalance between the two half-cell electrolytes that arises as a result of the differential transfer of ions across the membrane and the inevitable gassing side reactions that can occur during charging. While a number of methods are available to rebalance electrolyte state of charge and restore capacity, reliable methods are needed to monitor the state-ofcharge of each individual half-cell solution in order to determine the appropriate action to be taken by the battery control system. In this study different methods of state-of-charge monitoring have been considered for application in the All-Vanadium Redox Flow Battery (VRB). Half-cell potentials and electrolyte conductivities were calibrated as a function of state-of-charge and evaluated for state-of-charge monitoring of individual half-cell electrolytes for the purpose of capacity restoration and control. An empirical model based on experimental conductivity data has been shown to provide accurate predictions, with an average error of 0.77%, of the conductivity of the positive half-cell electrolyte as a potential state-of-charge detection tool. Separate monitoring of the two half-cell electrolyte potentials has also been used to determine the state-of-charge of each half-cell solution in order to detect system imbalance. This was used in small laboratory cell tests to determine necessary actions to restore capacity by either remixing the two solutions, or by using chemical rebalancing methods, depending on the cause of the solution imbalance.
Keywords: vanadium redox flow battery; state-of-charge monitor; capacity loss; cell rebalancing