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Availability of toxic elements in roadside soils (highway 75, Vojvodina, Serbia): is there any significant contamination risk?
No full textIn this paper we provide the observations of a group of toxic elements Cu, Pb, Cr, Co, Ni, Pb, V, Zn, Sb, and Mo, in the soils that are sampled at the distances of 1 m and 5 m (two layers) from the road (Highway 75, north section). The observation of toxic elements are indicating a level of the existing contamination, availability and ecological risk. The mean values of the content of the elements Cr, Cu, Mo, Pb, Sb and Zn are lower with respect to the reference MAC values, whereas the mean and particular values of the content of Co, V, and Ni are higher. The content of the Sb, Pb, Мo, Cr, Cu, V and Zn reach higher values in the surface layer near to the road – at a distance of 5 m. The particular values of Pb, Zn and Cu only in the surface samples, at both distances, at two sampling localities, are indicating the presence of anomaly. However, the results of the content of the elements in most mobile forms are suggesting a presence of insignificant content of the toxic elements, which can easily become available to the environment and spread by streams or groundwater. The results of the Risk assessment code (RAC) confirms that there is a lower risk of contamination of the near-road environment by these toxic element
Discovery of hyperalkaline waters in the ophiolites of western Serbia: Environmental considerations for carbon capture and sequestration
No full textRecently on-land ophiolites as unconventional reservoirs and hyperalkaline groundwaters have come out as a viable solution for natural atmospheric CO2 uptake/storage. However, the possibility of employing ophiolites and rare hyperalkaline waters as means or repositories of the anthropogenic CO2 has not been studied and no case study for Serbia has been introduced so far. Extremely rare on a global scale, but quite frequent are hyperalkaline groundwaters from the western Serbia that emanate from the wide supra-crustal Jurassic on-land ophiolites. Once discharged at Earth's surface, such groundwaters react with natural CO2 and produce carbonates. As such, the ophiolites and associated hyperalkaline groundwaters represent an important environmental factor of Serbia, allowing highly perspective development of the carbon capture and sequestration facilities across the area. The surface-exposed, ca. 20–30 km wide, mainly Jurassic massifs of ophiolite-bearing crustal units of western Serbia, are occur as two belts: Inner Dinaride Ophiolite belt and Vardar Zone. The composite geologic and hydrogeological field study shows that these unconventional reservoirs have several natural hyperalkaline springs (pH > 10.5), with the possibility of promoting fracturing and in-situ mineralization. By promoting the presence of very rare hyperalkaline groundwaters across western Serbia, this study attempts (i) to quantify the natural volume of hyperalkaline groundwaters (basic regional hydrogeology), emphasizing (ii) a preliminary natural degassing/carbon capture potential.Časopis je do kraja 2022. imao naziv "Journal of Petroleum Science and Engineering
BENEFITS OF ECONOMIC ENTITIES THROUGH THE CO-COMBUSTION OF VARIOUS CLONES FROM THE SALIX SP. GENUS AND A MIXTURE OF DIFFERENT LIGNITE SAMPLES
No full textPower generation depends to a great extent on the use of fossil fuels (lignite) in the Republic of Serbia. During
the previous years, inadequate decisions on the development of energy and the operation of coal mines and thermal
power plants led to a significant reduction in the power generation in coal-fired thermal power plants, and thus to the need
to import part of the electricity. On its green road “Go Green Road” that leads to decarburization, the Republic of Serbia
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intends to significantly increase the use of renewable energy resources, which would compensate for the shortfall in the
base portion of the daily load diagram, which threatens to be the greatest possible in the future. Due to economic reasons,
the introduction of innovations is only acceptable to energy producers if it does not deviate significantly from mainstream
technology, that is, if it is not necessary to invest too much in the reconstruction of already existing energy production
facilities. The objective of this paper is to present the biomass energy potential of various willow clones that would be
combusted, according to different percentage ratios, in a mixture of different coal samples taken from the Mining Basin
Kolubara in the Public Enterprise “Electric Power Industry of Serbia”. White willow clone NS 73/6 (Salix alba) had the
highest energy potential compared with other tested willow clones. From an economical point of view, it is more reasonable to select 5 % of the Salix alba NS 73/6 clone biomass, in the co-combustion process with lignite.
The paper is based on the principles of the circular economy, which would connect science and the economy
by implementing scientific and research findings into the economy, all aimed at protecting and preserving the
environment. By applying “green” technologies to the economy, the issue of protecting the environment can be
solved through simultaneous revenue generation for economic entities
Ni-MoO2 as electrocatalyst for hydrogen evolution reaction
No full textTaking into consideration global pollution caused by transforming fossil fuel into energy, it is necessary to make a transition to cleaner energy source. Hydrogen is a promising candidate, due to the fact the production can be carried out through electrolysis using renewable energy, and also conversion of hydrogen to energy leaves no pollutants. Zero-gap flow electrolyzers are usually used for hydrogen production on industrial level, in alkaline enviroment. In this type of systems electrodes should be porous (for better electrolyte flow), and the role of electrocatalyst can be carried out by earth abundant metals. Our research group uses Ni foam with open-pore structure and average pore size of 450 µm as a substrate on which Ni was electrodeposited along with MoO2 particles. In order to find optimal deposition conditions, a lot of parameters were varied such as current density, size of the MoO2 particles and their concentration, deposition bath and method of mixing the solution. On such prepared electrodes activity for HER was investigated in H-cell in 1M KOH at room temperature. The best samples were characterized by SEM and EDS analysis and tested in a zero-gap flow electrolyser where 8M KOH (70 °C) was used as electrolyte. In addition, preliminary stability tests were conducted and showed improvement of activity over time
Micromachines, Special Issue: Nanostructures for Application in Electronics and Renewable Energy Sources
No full textIn recent years, the development of nanostructures has revolutionized how we think about energy production, storage, and utilization. Using nanoscale materials and devices allows us to create efficient, high-performance, and cost-effective electronic systems that can be integrated into an extensive field of applications, from energy harvesting and storage to sensors and actuators.
This Special Issue of Micromachines is focused on the exciting field of nanostructures for application in electronics and renewable energy sources. Our goal is to provide a comprehensive platform for researchers and scientists to publish their cutting-edge work and foster interdisciplinary collaboration in this rapidly evolving area.
To this end, we welcome submissions that explore the latest advances in the synthesis and characterization of nanostructures, their integration into energy-harvesting devices and energy storage systems, as well as their application in the fields of electronics, renewable energy, and sustainable energy technologies.
We are particularly interested in articles that showcase the interdisciplinary nature of this field and its impact on a wide array of industries and applications, from aerospace and defense to biomedical devices. In this issue, we aim to provide a comprehensive overview of the state-of-the-art nanostructures for electronics and renewable energy sources, highlighting the key challenges and opportunities facing this field.This special issue belongs to the section "E：Engineering and Technology"
High temperature humidity sensing ability of indium-doped barium cerate
Get PDFAcceptor-doped perovskites (ABO3 general formula) with large lattice constants (such as BaCeO3, SrCeO3, and BaZrO3) have been known as fast proton conductors. The ability to conduct protons at high temperatures makes them suitable for humidity sensors in a high-temperature environment. The presence of traces of humidity can play a key role in the functioning of certain industrial processes at higher temperatures. Electrical characteristics of BaCe0.75In0.25O3–δ (BCI25) sintered sample were analyzed in a dry and a wet argon atmosphere in the 250–700 °C temperature range. The water vapor sensing properties of BCI25 porous film and its response and recovery times were investigated under different conditions of temperature and water vapor concentration. A 30 μm thick film obtained from the powder calcined at 1050 °C exhibited sensitivity comparable to that of the sintered sample with significantly shorter response and recovery times. While the sensitivity of the film gradually decreased with a decrease in partial pressure of water vapor (p(H2O)), a noticeable sensitivity was still observed at p(H2O) of 200 Pa. Decrease in conductivity depended logarithmically on the partial pressure of water with the slope of 0.52 that is close to the theoretical value. After several cycles, the reusability test proved an almost unchanged ratio between the impedance value in the dry and the wet Ar atmosphere (p(H2O) = 2.34 kPa), which implied that BCI25, having good stability and sensitivity, is a promising high-temperature humidity sensor
2 in 1versus 1plus 1 – Outcomes of the transformation of adsorptive stripping method for the Ni2+ and Co2+ determination
No full textDue to the similar chemical properties of Ni2+ and Co2+, several dozens of adsorptive stripping voltammetric (AdSV)
methods have been developed for their simultaneous determination. The question was would there be some benefits
if a stripping method made for simultaneous determination of Ni2+ and Co2+ will be optimized for the determination
of only one of them (Ni2+). It was found that the optimized method has for an order of magnitude lower LOQ (1.89 ×
10-10 M), an order of magnitude lower influence of Co2+, and the applicability of one calibration line for four orders
of magnitude of Ni2+ concentration. The influence of some common anions and cations has been examined. The
developed method was successfully applied for nickel content determination in real samples. The suitability of the
developed method for the determination of Co2+ from the same solution in the second run, upon optimizations of
deposition potential and time, was also explored. The LOQ obtained for Co2+ (3.61 × 10-11 M) is almost two orders
of magnitude lower than LOQ of the method for simultaneous determination of both cations and, its LOD and LOQ
are among few lowest obtained by AdSV methods for Co2+ determination. The developed method for Ni2+ and Co2+
determination from the same solution in two successive runs has significantly better analytical performances than
the starting method for their simultaneous determination in one run
Green Hydrogen Renewable Energy Based Society for Sustainable Economic Development-Challenges and Perspectives
Get PDFGreen Hydrogen Renewable Energy Based Society for Sustainable Economic Development-Challenges and Perspectives
Nevenka R. Elezovic
University of Belgrade – Institute for Multidisciplinary Research, Center of Excellence for Green Technologies, Kneza Viseslava 1, 11000 Belgrade, Serbia
Email: [email protected], corresponding author
The contemporary industry is mainly based on fossil fuels to be exhausted in near future. It causes environment pollution and greenhouse effect. During the last century the CO2 concentration increased 20%, raising average temperature on Earth. It means undesirable climate changes, biodiversity disorder and natural disasters. The development of alternative power sources is needed.
United Nations had recognized problem and global actions have already taken. European Union established main targets until 2030- Climate and Energy Package. The Paris Agreement (2015) adopted by 196 Parties from all over the world facilitated low-carbon solutions. Zero-carbon solutions are increasing in economy, especially the power and transport sectors.
˝The global climate fight will be won or lost in this crucial decade – on our watch. So let’s fight together– and let's win˝ (A. Guterres, UN General Secretary-November 2022).
Thus, development of hydrogen production and fuel cells as zero-emission technologies is needed, to achieve sustainability and circular economy. Hydrogen is high efficiency and environmental friendly fuel. It is produced by water electrolysis, industrial procedure processed in alkaline solution, at 80oC. The main disadvantage is still high energy consumption (~ 5kWh m-3 H2). The hydrogen fuel is used in fuel cells, while oxidative agent is oxygen from air. Many researchers' efforts were done to make progress in this area during past decades. State-of-the-art catalysts are noble metals (carbon supported Platinum) – still expensive for large-scale commercial use. In this research novel solutions for fuel cells catalysts based on low loading precious metals were investigated. Higher efficiency and durability were achieved if compared to commercial Pt/C. Comparative study on Platinum and Palladium based catalysts was presented. Challenges and perspectives were discussed in terms of technological, social and financial issues. Trading and prices of noble metals were discussed, as well.
Keywords: Renewable energy; Sustainable economic development; Hydrogen production; Fuel cells;, Zero-emission
Razvoj novih materijala za niskotemperaturne gorivne ćelije-izazovi i perspektive
Get PDFRazvoj novih katalizatora za niskotemperaturne gorivne ćelije-izazovi i perspektive
Nevenka R. Elezovic1
1 Univerzitet u Beogradu, Institut za multidisciplinarna istraživanja, Kneza Višeslava 1, 11030 Beograd, Srbija
*adresa za korespondenciju: [email protected]
Niskotemperaturne gorivne ćelije pripadaju grupi obnovljivih, ekološki prihvatljivih izvora energije. Primena zelenog vodonika kao čistog goriva, dobijenog elektrolizom vode, doprinosi zaštiti životne sredine, dostizanju održivog ekonomskog razvoja i cirkularne ekonomije, kao imperativa u procesu energetske tranzicije sa fosilnih goriva ka obnovljivim izvorima energije.
U ovom radu će biti dat pregled razvoja novih materijala za katalizatore u reakcijama redukcije kiseonika i oksidacije vodonika, koje se odbvijaju u niskotemeraturnim vodoničnim gorivnim ćelijama. Naime, današnji komercijalni katalizatori su na bazi platine dispergovane na ugljeničnim nosačima razvijene površine-komercijalno nazvanim Vulkan XC-72 i Ketjen Black. Nedostatak ovih katalizatora je nedovoljna stabilnost, posebno na anodnim potencijalima 1.4 V prema reverzibilnoj vodoničnoj elektrodi, velika cena platine i još uvek velika masa Pt potrebne za isplativu masovnu komercijalizaciju, posebno za redukciju kiseonika, usled velike prenapetiosti i spore kinetike [1,2]. Razvoj novih katalizatora i nosača na bazi metalnih oksida [3] - titanijuma, kalaja, wolframa, kao i drugih neorganskih keramičkih materijala – karbida, nitrida [4] obeležio je poslednjih par decenija u radovima svetskih i naših naučnika iz ove oblasti. Diskutovane su prednosti i nedostaci ovih novih katalizatora u odnosu na komercijalno zastupljene. Takođe je prikazana uporedna analiza aktivnosti i stabilnosti novih platinskih katalizatora na neugljeničnim nosačima u odnosu na komercijalne.
Zahvalnica
Ovaj rad je finansijski podržalo Ministarstvo nauke, tehnološkog razvoja i inovacija Republike Srbije, u okviru ugovora br. 451-03-47/2023-01/ 200053
Literatura
[1] 1 A. Morozan, B. Jousselme and S. Palacin, Low-platinum and platinum-free catalysts for the oxygen reduction reaction at fuel cell cathodes, Energy Environ.Sci., 4(2011) 1238.
[2] H. A.Gasteiger, J.E.Panels, S.G.Yanet, Dependence of PEM fuel cell performance on catalyst loading, J. Power Sources 127 (2004) [3] N. R. Elezovic, V. R. Radmilovic and N. V. Krstajic, Platinum nanocatalysts on metal oxide based supports for low temperature fuel cell applications, RSC Adv.,6 (2016) 6788.
[4] Q. Sun, X.H. Li, K.X Wang, T.N. Yea and J.S. Chen, Inorganic Non-carbon Supported Pt Catalysts and Synergetic Effects for Oxygen Reduction Reaction, Energy Environ.Sci., in press (2023)
ADVANCED OPTICAL TOOLS APPLIED ON HONEY SAMPLES FOR BEE HEALTH STATUS MONITORING
Get PDFHoney bees have a very important role in pollinating plants, in addition to honey production. Bee
diseases are one of the reasons of a significant decrease in bee colonies in the world in recent years. Honey samples originating from hives with different infestations with N. ceranae were analyzed. Total phenolic content and total protein content were determined by the Folin-Ciocalteu assay and the Bradford assay, respectively. Fluorescence spectroscopy combined with PARAFAC was used to determine the spectral components originating from proteins (PFSC1) and phenolics (PFSC2) in honey samples, and their ratios were calculated. Phenols and proteins content in the honey samples, obtained by spectrophotometric quantification, decreases with increasing infestation levels in the respective hives infected with N. ceranae. A negative correlation was obtained for the ratio of PARAFAC components PFSC2/PFSC1 and the level of infestation with N. ceranae in honey samples. These results indicate that fluorescence spectroscopy combined with PARAFAC could be used as an optical tool for non-invasive and rapid screening of honey to estimate bee health status