Effect of steel slag on growth and physiology of corn (Zea mays L.)

Bazična troska koja se koristi u ovom istraživanju je nusproizvod pri proizvodnji čelika u elektrolučnoj peći. Obzirom da je sadržaj P, Fe, Ca, Mg i Mn u tako dobivenoj troski visok, a sadržaj Cd, Pb, Hg i ostalih toksičnih teških metala vrlo nizak, usitnjena troska je potencijalni izvor mineralnih tvari za rast i razvoj biljaka, posebice na tlima siromašnim željezom. Cilj istraživanja bio je procijeniti učinkovitost troske kao izvora određenih hranjivih elemenata na rast i fiziološke procese kukuruza te utvrditi da li troska u biljci dovodi do oksidacijskog stresa kao posljedica primanja povećanih količina Fe i Cu. Kao supstrati za sadnju biljaka korištene su mješavine zemlje i pijeska u različitim omjerima. Sjemenke kukuruza su zasijane u posudice i napunjene samo supstratom (kontrola) ili supstratom uz dodatak fino mljevene troske. Nakon dva tjedna, dijelu kontrolnih biljaka kao i onih uzgojenih uz dodatak troske dodan je NH4NO3 kao izvor N. Dijelu kontrolnih biljaka koje služe kao pozitivna kontrola dodano je tekuće gnojivo – NPK i Fe. Osim parametara rasta, izmjerena je fluorescencija klorofila i prinos suhe tvari biljaka, sadržaj mineralnih tvari u supstratu i listovima biljaka, sadržaj klorofila i karotenoida, lipidna peroksidacija te aktivnosti antioksidacijskih enzima. Rezultati su pokazali da je troska vrlo dobar i jeftin izvor mikroelemenata poglavito Fe, Mn i Mg potrebnih biljci te da se njezinom upotrebom znatno smanjuje kloroza listova u biljaka koje rastu na tlima siromašnim željezom.Basic slag used in this study is a byproduct in the production of steel in electric arc furnaces. Given that the content of P, Fe, Ca, Mg and Mn in the slag is high and those of Cd, Pb, Hg and some other toxic heavy metals is very small, finely ground slag is a potential source of minerals necessary for plant growth and development, especially on iron-poor soils. The aim of this study was to evaluate the effects of steel slag, as a source of specific nutrient elements, on growth and physiological processes of corn and to determine whether steel slag can induce oxidative stress in plant cells. A mixture of earth and sand in different proportions was used as a substrate for planting. Corn seeds were sown in containers and filled with either pure substrate (control) or substrate mixed with finely ground slag. After two weeks, control plants and those grown with the addition of slag were supplemented with NH4NO3 as a source of N. A part of control plants that served as a positive control was supplemented with liquid fertilizers - NPK and Fe. Beside growth parameters, chlorophyll fluorescence, dry matter yield of plants, mineral content in the substrate and plant leaves, chlorophylls and carotenoids content, lipid peroxidation and antioxidant enzyme activities were measured after six weeks of cultivation. The results showed that steel slag is a very good and inexpensive source of microelements especially Fe, Mn and Mg essential to plants and that its usage significantly reduces leaf chlorosis in plants growing on iron-deficient soils

Solvothermaly synthesized copper doped bismuth vanadate

Photoeletrochemical (PEC) water splitting is a promising method for clean energy production and different oxide materials have been explored to find the right solution. Among them, as one of the most promising photoanode materials, bismuth vanadate (BiVO4) has attracted a lot of attention due to the suitable band gap edge alignment, lowcost synthesis method and great visible light harvesting features. Nowdays, research related to the BiVO4 is mostly oriented towards repairing poor charge transfer properties which exist due to the high rate of electron–hole recombination. Metal doping is one of the strategies to improve these intrinsic drawbacks. Herein, we report physicochemical properties of solvothermaly sinthesized pristine BiVO4, 1%-, 2.5%- and 5%- Cu-doped BiVO4 powders at 180 ºC for 8 h. X-ray diffraction (XRD) study indicates that, depending on the degree of doping, material exists in monoclinic or tetragonal scheelite phase. Pure monoclinic phase was formed in a case of pristine, 1%- and 2.5%- Cu doped samples. After doping with 5 %, phase transition occurred and material showed tetragonal phase. Scanning electron microscopy (SEM) reveals that samples with monoclinic phase consists of worm-like and prismatic structures while tetragonal samples exhibited spherical shape. Furthermore, structure was examined with Raman and FTIR spectroscopy. The results were in accordance with diffraction study where band positions were well matched with phase composition. Optical properties were characterized with UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. Monoclinic samples showed band gap around 2.4 eV, while sample with tetragonal phase has band gap around 2.8 eV. PL showed that that monoclinic samples possess better recombination features than tetragonal ones. Photoelectrochemical measurements suggest that material is sensitive towards visible light and, after doping, improved its performance towards oxygen evolution reaction.8th Conference of Young Chemists of Serbia; 29th October, Belgrade, Serbi

Photoelectrochemical water oxidation properties of bismuth vanadate photoanode irradiated by swift heavy ions

Photoelectrochemical (PEC) water splitting is a promising route for solar energy harvesting and storage. The most challenging obstacle for efficient water splitting is development of catalysts for oxygen evolution reaction (OER). Monoclinic bismuth vanadate (BiVO4, BVO) stands out as an excellent photoanode material due to its high stability in near-neutral electrolytes, suitable band structure and low-cost synthesis. However, pronounced charge recombination is a huge limiting factor and understanding the effects contributing to it is important for further improvements. In present study, we report the effect of swift heavy ion (SHI) irradiation (Xe, 150 MeV, 1 × 1010 – 5 × 1011 ions cm-2 ) on physicochemical properties of hydrothermally synthesized BVO thin films. X-ray diffraction (XRD) study showed that irradiated material preserved initial monoclinic scheelite phase and preferential growth along [010] direction together with the presence of notable amorphization at the highest fluence. Scanning electron microscopy (SEM) of all samples showed prismatic grains with an average size of 600 nm with the appearance of ion tracks after irradiation. More detailed examination of 1 × 1010 ions cm-2 irradiated sample by transmission electron microscopy (TEM) revealed presence of amorphous ion tracks (~ 10 nm in diameter) and hillocks at the BVO surface (~ 10 nm in height). Raman spectra showed bands that correspond to the monoclinic scheelite phase as well as the presence of new bands for 5 × 1011 ion cm-2 irradiated sample at 420 and 915 cm-1 that originate from complex vanadium oxides. X-ray photoelectron spectroscopy (XPS) after SHI irradiation showed an increase of V4+ states and oxygen vacancies, especially at higher fluences. Diffuse reflectance spectroscopy (DRS) measurements showed decrease of band gap with the increase of fluence. Photocurrent densities, obtained from 1-hour-long chronoamperometry measurements, showed that irradiation with 1 × 1010 ions cm-2 fluence leads to gradual recovery of PEC oxygen evolution with time. XRD, SEM and XPS measurements performed after PEC reveal complex changes in the BVO, including dissolution of the material along ion tracks.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

The role of copper doping on physicochemical properties of bismuth vanadate

Production of gasses such as hydrogen and oxygen on a large scale is of the great importance both in industry and in environmental protection. To achieve it, photoelectrochemical (PEC) water splitting has been regarded as promising method and the developement of new semiconductors holds a key role to the efficent application. Due to its great light harvesting ability, band edge positions and low-cost synthesis method, bismuth vanadate (BiVO4; BVO) has been intensively studied as a photoanode material for water splitting. To overcome limitations such as charge carriers recombination, material should be doped with different transition metal elements. In this work physicochemical properties of pristine and 1%-, 2.5%- and 5%- Cu-doped BVO powders, solvothermaly synthesized at 180°C for 20 h, were reported. X-ray diffraction (XRD) study indicates that, depending on the doping level, the material exists in monoclinic or tetragonal scheelite phase, but mixed phase composition was also observed. Pure monoclinic and tetragonal phase was formed in a case of pristine and 1% doped sample, respectively, while 2.5%- and 5%- Cu-doped BVO exhibit presence of both phases. Scanning electron microscopy (SEM) reveals that sample with monoclinic phase consists of irregular worm-like morphology, while morphology of tetragonal samples was mostly spherical. For 2.5%- and 5%- Cu-doped samples a combination of prismatic and spherical shape morphology was observed. Local structure of material was examined with Raman spectroscopy and the results were in accordance with XRD study where band positions well matched the phase composition. Optical properties were characterized with UV-Vis Diffuse Reflectance Spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. The band gap of monoclinic samples was in range 2.4-2.5 eV, while band gap of sample with tetragonal phase has band gap was between 2.8 and 3 eV. Dual phase samples had two different band gaps that originate from presence of both phases. Based on the results obtained from the PL spectra, monoclinic samples possess better recombination features than tetragonal ones. Photoelectrochemical measurements of BVO samples imply that doping of material improves performance towards oxygen evolution reaction.Twentieth Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 30 – December 2, 2022, Belgrade, Serbi

Enhanced electrochemical detection of gallic acid using modified glassy carbon electrodes with Zn/Ga-dopped cobalt ferrite

In this study, solvothermally synthesized nanoparticles of cobalt ferrite (CoFe2O4, CFO) and Zn/Ga-dopped cobalt ferrite (Co0.5Zn0.5Fe2O4, CFO_Zn and CoFe1.5Ga0.5O4, CFO_Ga, respectively) with dihydrocaffeic acid (DHCA) as a surfactant were examined for electrochemical detection of gallic acid. Based on X-ray diffraction analysis, diffraction maxima of all samples correspond to the cubic spinel phase, while transmission electron microscopy showed that the nanoparticles are non-agglomerated, sphere-like with an average size of 5±1 nm. The presence of DHCA on the surface of nanoparticles was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). For the purpose of electrochemical detection of gallic acid the modified glassy carbon electrode (m-GCE) was prepared from CFO, CFO_Zn and CFO_Ga nanoparticles. Initial tests have shown instability/disintegration of m-GCE in aqueous solutions, because of which samples were annealed at 450 °C in air. Cyclic voltammograms of all annealed samples showed good reversibility in the system [Fe(CN)6] 3-/4- . The most efficient electron transfer was achieved when the mass ratio between sample and Nafion® was 85:15, respectively. The best sensitivity to gallic acid (10-4 M, in Britton-Robinson buffer) was observed for CFO_Zn sample. Results are showing that by selective functionalization and surface modification of nanoparticles, it is possible to optimize the electrochemical properties suitable for sensing, which is the basis of this method and the goal of further research.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Gravity waves excited during a minor sudden stratospheric warming

An exceptionally deep upper-air sounding launched from Kiruna airport (67.82∘ N, 20.33∘ E) on 30 January 2016 stimulated the current investigation of internal gravity waves excited during a minor sudden stratospheric warming (SSW) in the Arctic winter 2015/16. The analysis of the radiosonde profile revealed large kinetic and potential energies in the upper stratosphere without any simultaneous enhancement of upper tropospheric and lower stratospheric values. Upward-propagating inertia-gravity waves in the upper stratosphere and downward-propagating modes in the lower stratosphere indicated a region of gravity wave generation in the stratosphere. Two-dimensional wavelet analysis was applied to vertical time series of temperature fluctuations in order to determine the vertical propagation direction of the stratospheric gravity waves in 1-hourly high-resolution meteorological analyses and short-term forecasts. The separation of upward- and downward-propagating waves provided further evidence for a stratospheric source of gravity waves. The scale-dependent decomposition of the flow into a balanced component and inertia-gravity waves showed that coherent wave packets preferentially occurred at the inner edge of the Arctic polar vortex where a sub-vortex formed during the minor SSW

Influence of N5+ ion irradiation on physicochemical properties of bismuth vanadate

Photoelectrochemical (PEC) cells for solar-energy conversion have received huge interest as a promising technology for renewable energy production. For the efficient application of such cells, it is necessary to develop adequate photoelectrodes. Recently, bismuth vanadate (BiVO4) has emerged as a promising photoanode due to its visible light harvesting properties, band edge positions and low-cost of synthesis. In this study, the effects of N5+ ion irradiation (75keV, 2 × 1014 and 4 × 1014 ions/cm2 ) on physicochemical properties of hydrothermally synthesized BiVO4 thin films were examined. From X-ray diffraction (XRD) study can be concluded that initial monoclinic material didn’t sustain any phase transition after irradiation. Also, preferential orientation remained dominantly along [010] direction with a slightly increasing share of [121] oriented growth, especially after irradiation with 2 × 1014 ions/cm2 . XRD measurements showed shift towards the higher 2θ after irradiation which indicates that interplanar distances decreases. The highest level of crystallinity was observed for the sample irradiated with fluence of 4 × 1014 ions/cm2 . Scanning electron microscopy (SEM) revealed prismatic morphology of all samples with an average grain size of 600 nm without visible traces of irradiation.Raman spectroscopy confirmed presence of bands that correspond to the monoclinic scheelite phase. X-ray photoelectron spectroscopy (XPS) analysis of V 2p confirmed presence of V5+ and V4+ while analysis of O 1s confirmed presence of oxygen in the form of lattice oxygen and in the form of hydroxide. UV-Vis Diffuse Reflectance spectroscopy revealed that calculated band gap decreases with the increase of fluence

The effect of swift heavy ion irradiation on physicochemical properties of monoclinic bismuth vanadate

Monoclinic bismuth vanadate (BiVO4) is considered to be one of the most promising photoanode materials for photoelectrochemical (PEC) water splitting due to its suitable band gap and band structure, good stability and low-cost synthesis. However, BiVO4 has poor charge transfer properties due to the high rate of electron-hole recombination and understanding the effects contributing to it is important for further improvements. Herein, we report the effect of swift heavy ion irradiation (Xe, 150 MeV, 1010 – 5×1011 ions/cm2 ) on physicochemical properties of hydrothermally synthesized BiVO4 thin films. X-ray diffraction study (XRD) showed that irradiated material preserved initial monoclinic scheelite crystal phase and preferential growth along [010] direction. As the fluence increased, a shift of the diffraction maxima towards lower 2θ values was observed indicating increased interplanar distances. Also, for the 5×1011 ions/cm2 irradiated sample, high degree of amorphization was noticed. Scanning electron microscopy (SEM) of all samples showed prismatic grains with an average size of 600 nm. In irradiated samples formation of ion tracks, ~10 nm in diameter, was observed. X-ray photoelectron spectroscopy (XPS) analysis of Bi 4f, V 2p and O 1s states showed that, after irradiation, increased amounts of V4+ and oxygen in the form of hydroxide occurred, especially at higher fluences. By using UV-Vis Diffuse Reflectance spectroscopy we showed that band gap decreased with the increase of fluence. Photocurrent densities obtained from linear sweep voltammetry indicated that irradiation with fluences higher than 1010 ions/cm2 have a notable negative effect on PEC oxygen evolution reaction. However, 1-hour-long chronoamperometry measurements of 1010 ions/cm2 irradiated sample revealed an increase of photocurrent densities. In order to get a better insight into preceding phenomena, we performed XRD, SEM and XPS analysis after PEC process

Physicochemical properties of bismuth vanadate photoanode irradiated by swift heavy ions

Program and book of abstracts / 2nd International Conference on Innovative Materials in Extreme Conditions i. e. (IMEC2024), 20-22 March 2024 Belgrade, Serbia

Sinteza i modifikacija naprednih nanomaterijala - pogled kroz prizmu obnovljivih izvora energije

Elektrohemijska istraživanja su prethodnih godina dala ključni podstrek globalnim stremljenjima ka obnovljivim izvorima energije. Višegeneracijski napori, u početku motivisani željom za fundamentalnim razumevanjem procesa, aktuelizovani su očekivanim nedostatkom fosilnih goriva i pratećim nepovoljnim uticajem na životnu sredinu. Nanomaterijali su omogućili spektakularan skok u tehnološkim inovacijama i neosporan je njihov doprinos obnovljivim izvorima energije. Zahvaljujući novim svojstvima nanomaterijala i njihovoj sinergiji, omogućeno je dalje unapređenje i integracija različitih funkcionalnosti. Pri tome, postalo je jasno da atomski precizan dizajn materijala postaje kritičan za razvoj naprava sledeće generacije. Ovo je posebno važno u slučaju nanokompozita gde interakcija komponenti pojačava moguće sinergijske doprinose. U izlaganju će biti dat osvrt na napredne metode sinteze i modifikacije materijala – od tradicionalnih, do tankih filmova, 0D i 2D nanomaterijala i njihovih kompozita – posmatranih kroz prizmu obnovljivih izvora energije i održivosti (elektrohemijski superkondenzatori, razgradnja vode, senzori, i dr.). Razvoj novih materijala i unapređenje elektrohemijskih sistema ima potencijal da suštinski učini obnovljivu energiju održivijom i dostupnijom, time otvarajući put ka održivoj budućnosti.Savremena stremljenja u elektrohemiji u proceu prelaska na obnovljive izvore energije: Naučni skup posvećen 100 - godišnjici rođenja inostranog člana SANU Dž. O'M. Bokrisa; 5. Jun, Beograd, 2023