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Influence of Spent Fluid Catalytic Cracking Catalyst on the Properties of the New Binder Based on Fly Ash and Portland Cement
Get PDFOne of the measures to reduce the carbon footprint of the Portland cement (PC) manufacturing process is through a wider use of supplementary cementitious and waste materials. The main objective of this work was to produce a new binder using two different waste materials: fly ash FA) from thermal power plants and spent fluid catalytic cracking catalyst (sFCCC) from petrol refineries. In order to improve their reactivity, both FA and sFCCC were mechanically activated prior to the preparation of the binder. The new binder consisted mostly of the waste materials (70 mass %), with PC as a minor component (30 mass %). It was found that using sFCCC as the binder component accelerated cement hydration and the pozzolanic reaction. The new binder had a shorter setting time and a higher early strength than the binder prepared without sFCCC
In situ conservation of forest genetic resources at the locality „Duboka” in the National Park „Kopaonik” – Serbia
Get PDFIn situ conservation in Serbia is mainly presented in protected areas, such as national parks.
National Park „Kopaonik” is one of five national parks in Serbia, which covers a total area of
11,969.04 ha, including 13 localities with a protection regime of the first degree. Forest genetic
resources in the National Park „Kopaonik“ are affected by various biotic and abiotic threats
which lead to their genetic erosion. This research aimed to identify rare, endangered, relict,
endemic, and vulnerable forest trees at the locality „Duboka”, to assess their degree of
endangerment and propose conservation measures. The locality „Duboka” covers an area of
144.03 ha, at an altitude of between 1020 and 1780 m. By terrain reconnaissance, a total of 18
forest tree species, and 27 species in the shrub layer were identified, which indicates a
significant biodiversity of this locality. Nine forest tree species belong to the categories of rare
(rowan and wych elm), rare-endangered (silver birch), relict (European hop-hornbeam),
endemic (Balkan maple), and vulnerable species (aspen, wild cherry, wild pear, and whitebeam)
in Serbia. Among those species, it is very important to conserve the available gene pool of
European hop-hornbeam (Ostrya carpinifolia Scop.), which is a very rare, relict species that
occurs only in the locality „Duboka” in the entire area of Kopaonik, and the Balkan maple (Acer
heldreichii Orph. ex Boiss.), an endemic species whose range is drastically decreasing on the
entire Balkan peninsula. The measures of conservation and monitoring of individual genotypes
or groups of trees have been defined, and an assessment of the variability of gene pool using
genetic markers was proposed. In situ conservation units will include sites where all nine rare,
endangered, relict, endemic, and vulnerable forest tree species were selected and
georeferenced. The implementation of the proposed measures is expected in the following
period
Where do we stand on the knowledge of T. magnatum environments? Progress and new research hypotheses
Get PDFKnowledge about the environments of T. magnatum has been consolidated in the 2000s, confirming the importance of microclimate and that of specific soil types that, in fact, restrict the areas of natural spread of the fungus. In recent years, investigations have focused on two distinct themes: on the one hand, mycorrhization techniques have been refined, leading to the commercial production of mycorrhized plants and the establishment of the first experimental truffle orchards; on the other hand, the hydrological aspects of natural truffle areas, previously left in the background, have begun to be studied. The first topic has yielded interesting results with the start of production in areas never reported as productive and promises to expand the territories in which to "cultivate" T. magnatum. The second line of investigation is providing insights into the need for specific water management of truffles - natural and cultivated - focused on soil water conservation. For the future, it will be necessary to work in depth on this aspect. The natural environments of T. magnatum are characterized by a great need for water, which we hypothesize can be managed at the scale of micro-hydrographic basin, since the exclusive use of irrigation practices adopted, for example, for T. melanosporum is not economically viable
Gender structure of Tree-of-Heaven (Ailanthus altissima (Mill.) Swingle) in the protected natural area ‘Bajfordova šuma’ on the territory of Belgrade — the basis for biological control of its expansion and planned reduction
Get PDFPajasen (Ailanthus altissima (Mill.) Swingle) je invazivna vrsta u Srbiji, koja ugrožava floristički
biodiverzitet u prirodnim šumskim zajednicama i urbanim prostorima. To je heliofit, sa brzim
rastom u početnoj fazi razvoja i izraženom adaptivnom sposobnošću na različite uslove sredine
otvorenih staništa. Sa pojavom ranog polnog sazrevanja i, pretežno, svakogodišnjeg uroda
velike količine plodova, koji se lako prenose na veću udaljenost od matičnog stabla, pajasen
brzo kolonizuje prirodne šumske zajednice i urbane prostore. To je dvodoma drvenasta biljka.
Primenom polnog dimorfizma kod pajasena, kao kriterijuma za selekciju stabala u proredi,
može se uticati na širenje vrste generativnim putem, a u okviru sastojinskog sklopa može se
uticati na rast i održanje generativnog i vegetativnog potomstva. Diferenciranje rodnih-ženskih
od nerodnih-muških stabala vrši se u fazi cvetanja na osnovu cvetno-plodnih cvasti, a odabir
rodnih-ženskih stabala vrši se tokom cele godine na osnovu prisutnih plodova i cvetno-plodnih drški koje se dugo zadržavaju u krošnji po opadanju plodova. Polni dimorfizam ove vrste poslužio
je kao osnova za utvrđivanje polne strukture stabala u zaštićenom prirodnom dobru ,,Bajfordova
šuma” na području Beograda u cilju kontrole i zaustavljanja invazije u urbanom prostoru.
Na površini zaštićenog prirodnog dobra 40,08 ha pajasen je zastupljen pojedinačno ili u
grupama, u odsecima na ukupnoj površini 27,09 ha sa 131 polno izdiferenciranih stabala čiji su
prsni prečnici u rasponu 5-74 cm, a visine u rasponu 5-21 m.
U okviru navedenog broja polno izdiferenciranih stabala pajasena zastupljenost ženskih
i muških stabala je približno podjednaka, ali prostorno varira. Evidentirana ženska i muška
stabla osnova su za monitoring, plansku redukciju i gajenje pajasena u neinvazivnom obliku u
zaštićenom prirodnom dobru ,,Bajfordova šuma” u određenom prelaznom periodu.Tree-of-Heaven (Ailanthus altissima (Mill.) Swingle) is an invasive tree species in Serbia
that threatens the floristic biodiversity in natural stands and urban areas. It is a heliophyte with
rapid growth in the initial phase of development and a well-expressed adaptability to different
environmental conditions in open habitats. With early maturity and abundant fruiting almost
every year, and the ability of seeds to be transported far from the maternal tree, the tree-of-heaven
can rapidly colonize the stands (with disturbed stand structure) of other tree species. It is also
a dioecious woody plant. If gender dimorphism of tree-of-heaven is used as a criterion for tree
selection in thinning, it can be applied to affect the generative expansion of the species. Within
the stand canopy closure, it can be used to influence the growth and survival of generative and
vegetative offspring. Differentiation of fruit bearing-female and non-fruit-bearing-male trees
is carried out during the flowering phase on the basis of its inflorescences. Selection of fruitbearing-female flowers is carried out during the whole year by checking for the presence of
fruit and inflorescence petioles that are retained in the crown after the fruit shedding. Gender
dimorphism of the species served as the basis for the gender structure determination in the
protected natural area ,,Bajfordova šuma” in Belgrade.
Out of 40.08 ha of the protected natural area, tree-of-heaven was recorded individually or in
groups, in an area of 27.09 ha, with 131 sexually differentiated trees with diameters within the
range of 5-74 cm and heights within the range of 5-21 m.
Within the aforementioned number of trees, the share of female and male trees is almost
equal, but varies spatially. The recorded female and male trees are the basis for monitoring,
planned reduction and tree-of-heaven growing in a non-invasive form in the protected natural
area ,,Bajfordova šuma”
The coordination and storage of manganese in the microalga Haematococcus pluvialis
Get PDFHaematococcus pluvialis is a unicellular green alga of significant environmental and
economic impact, well adapted to life in extreme conditions such as metal pollution.
Manganese is a common pollutant of water bodies that is related to mining and industrial
drainage, and microalgae have been applied in their bioremediation. To study changes in Mn
redox and coordination form upon interaction with H. pluvialis cells, we exposed late
exponential/early stationary green phase culture to 1 mM MnCl2 (Mn2+) for 72 h. Applied
concentration exceeds microalgal physiological quota but it was non-toxic. Structure of
coordinated Mn in the cells was analyzed using X-ray absorption near edge structure
(XANES) and extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, while
visualization and elemental mapping of Mn was performed by micro X-ray fluorescence
(μXRF). XANES spectra showed that the oxidation form of Mn in H. pluvialis biomass
remained 2+. However, EXAFS showed Mn coordination in microalgae is closer to hydrated
MnSO4 with minor deviation of the local geometry. The shorter Mn-O bonds in biomass,
compared to crystal model, implies somewhat more stable complex in H. pluvialis. This
suggests that H. pluvialis may use sulphated polysaccharides for Mn sequestration, which
would be a newly proposed mechanism of metal coordination and storage. μXRF analysis
showed co-localization of Mn with O and Na, with particularly good superimposition for Mn
and O. O-rich regions may represent vacuoles, filled with organic acids including sulphates,
or starch granules and accumulations of sulphated polysaccharides, which are known to be
produced by H. pluvialis. In addition, vacuoles in plant cells are known to act as sinks for
Na+ ions. These findings are in line with structural analysis that showed dark precipitates in
vacuoles, which are likely accumulations of Mn
PHYTOCHEMICAL INVESTIGATION, ACUTE TOXICITY, ANTIOXIDANT AND ANTIDIABETIC ACTIVITY OF EXTRACTS FROM AERIAL PARTS OF FOUR WILD GROWING ACHILLEA SPECIES
Get PDFPlants from the genus Achillea are rich in biologically active ingredients and are traditionally known for their healing potential.
In this research, the phytochemical profile was investigated, the content of total phenolics and flavonoids was determined and
examined the acute toxicity, antioxidant and antidiabetic activity of ethanolic, ethyl acetate and chloroform extracts of Achillea
abrotanoides (Vis.) Vis., Achillea chrysocoma Friv., Achillea grandifolia Friv. and Achillea millefolium L. Tested extracts
showed the presence of different groups of phytochemicals, while the high content of total phenolics and flavonoids was
quantified, especially in the ethanolic and ethyl acetate extracts. The acute toxicity was examined in the Artemia salina model,
where the extracts did not show significant toxicity after an incubation period of 24 hours, while after 48 hours, strong acute
toxicity was recorded in chloroform extracts of A. millefolium and A. chrysocoma. Extracts were tested for antioxidant activity
using the DPPH test, as well as antidiabetic activity based on their ability to inhibit the α-amylase. Ethanol and ethyl acetate
extracts of A. abrotanoides and A. millefolium showed a great ability to reduce DPPH radicals, while the same extracts
accomplished a significant inhibitory potential on α-amylase. Also, a correlation was established between the content of total
phenolics and flavonoids with the antioxidant activity of the extracts
Green Hydrogen Energy Based Economy to Decrease Climate Changes for Environmental Friendly-Sustainable Development
Get PDFGreen Hydrogen Energy Based Economy to Decrease Climate Changes for Environmental Friendly-Sustainable Development
Nevenka R. Elrzovic
University of Belgrade, Institute for Multidisciplinary Research, Center of Excellence for Green Technologies, Kneza Viseslava 1, 11000 Belgrade, Serbia, [email protected]
Abstract: Intensive fossil fuel application leads to the growing environment pollution, causing the "greenhouse effect". During the 20th century the CO2 concentration increased about 20%, being the main reason for average temperature increase on Earth. This fact has already caused undesirable climate changes. United Nations has recognized environment pollution effects and global actions have already been taken. From Stockholm conference held in 1972 to COP 2022, United Nations announced several declarations to stabilize gas emission and decrease greenhouse effect. European Union has established main targets until 2030, in the frame of Climate and Energy Package, to increase alternative power sources usage and save environment. Thus, the further development of green hydrogen production and fuel cells catalysts as environmental friendly-green technologies are extremely desirable, to achieve sustainable economic development. Hydrogen – high efficiency and environmental friendly fuel, produced by water electrolysis is used in low temperature fuel cells, while oxidative agent is oxygen from air. In this work novel nanostructured materials with noble metal nanoparticles deposited onto ceramics based supports have been investigated as the catalysts for fuel cells, promising alternative power sources. Several ceramic supports were developed - Ti, Sn and W based oxides, doped by Ru or Nb to improve conductivity. Physical-chemical and electrochemical characterization of these novel materials confirmed higher efficiency and long term stability to decrease the costs and increase life time of fuel cells acceptable for commercial application.
Biography: Dr Nevenka R. Elezovic completed her PhD in 2005, from University of Belgrade. She is currently Research Professor at the Institute for Multidisciplinary Research, University of Belgrade. Her research interests: Nanostructured materials and alloys for low temperature fuel cells and water electrolysis applications – environmental friendly green energy production. Since 2013 she has been serving as national representative of Serbia and member of the European board in European Academy of Surface Technology: http://www.east-site.net. She has published more than 50 papers in high impact peer reviewed international journals and more than 70 conference papers. Web page:
http://www.imsi.bg.ac.rs/en/researchers/nevenka-r-elezovic
Details of the Presenting Author:
Nevenka R. Elezovic:
[email protected]
[email protected]
Serbia:
Presentation Category: Oral-Keynote lecture
Recent Photograph: (High Resolution
MAX phases as the catalysts support materials for green energy related applications
Get PDFMAX phases as the catalysts support materials for green energy related applications
Nevenka R. Elezovic
University of Belgrade-Institute for Multidisciplinary Research, Center of Excellence for Green Technologies, Kneza Viseslava 1, 11000 Belgrade, Serbia
*Corresponding Author E-mail: [email protected]
ABSTRACT
MAX phases – specific materials of general formula Mn+1AXn, (MAX) where n = 1 to 4, where M is early transition metal, A is element from the group of Al, Si or P and X is carbon or nitrogen, have attracted great attention in materials science, especially as high performance supports for noble metals group catalysts intended to be used for hydrogen production by water electrolysis, as well as for fuel cells reactions. These materials demonstrated good mechanical properties, high conductivity, high chemical and corrosion stability, especially in the potential range from hydrogen to oxygen evolution that is of great interest for low temperature fuel cells reactions. In this research ultra- low loading platinum layers were deposited onto Ti2AlC and (Nb-Ti)2AlC MAX phases supports and characterized as the catalysts for anode (hydrogen oxidation) and cathode (oxygen reduction) reactions for low temperature fuel cells. Physical-chemical characterization was performed by: Scanning Electron Microscopy (SEM), X-Ray Photoelectron Spectroscopy (XPS), Focus-Ion Beam High Resolution Transmission Electron Microscopy (FIB-HRTEM). The electrochemical characterization for both anode and cathode reactions was done by cyclic voltammetry and linear sweep voltammetry and very good activities were confirmed in comparison to carbon supported commercial catalysts. It should be emphasized that progress beyond state of the art was made in terms of lower Pt loading - being only 18.3 µg cm-2 (for HOR the state of the art is ≈ 50 µg cm-2, while for ORR 200 -400 µg cm-2). These novel catalysts exhibited high durability according to US DOE standardized tests, as well. It is worthy to mention that the support materials are low cost and electrodeposition, as well.
Acknowledgements: This work was financially supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Contract No. Contract No. 451-03-68/2022-14/200053). The author would like to thank Prof. M. Barsoum, Drexel University – Philadelphia PA 1 USA for preparation of MAX phases based substrates.
Keywords: Fuel cells; MAX phases; ORR and HOR catalysts; low Pt loading layers;
Biography: Dr Nevenka R. Elezovic completed her PhD in 2005, from University of Belgrade. She is currently Research Professor at the Institute for Multidisciplinary Research, University of Belgrade. Her research interests include: Nanostructured materials and alloys for low temperature fuel cells and water electrolysis application - green energy production. Since 2013 she has been serving as representative of Serbia and member of the European board in European Academy of Surface Technology,http://www.east-site.net. She has published more than 40 papers in reputed peer reviewed journals of eminent Publishers such as Elsevier, Royal Society of Chemistry, The Electrochemical Society and more than 70 conference papers. She has been serving as a reviewer for: Energy and Environmental Science, Applied Materials and Interfaces, Journal of Materials Chemistry A, Electrochimica Acta, Applied Catalysis B: Environmental, RSC Advances, Journal of the Electrochemical Society, International Journal of Hydrogen Energy, as well as adjudicative (senior) reviewer for Energy and Environmental Science and Journal of Materials Chemistry A. She has given numerous invited lectures at the International conferences, recently at International Summit on Conventional and Sustainable Energies, March 30-31, 2018 Orlando, Florida, USA; Global Experts Meeting on Frontiers in Green Energy and Expo, October 14-16, 2019 Rome, Italy; Materials, the Building Block for the Future 3rd AAAFM-UCLA conference, August 18-20 2021 Los Angeles USA; Euro-Global Climate Change Conference, September 19-20, 2022 Paris, France
AN ALTERNATIVE CONCEPT OF URBAN GREENING: URBAN PHOTOBIOREACTOR LIQUID3
Get PDFLimited space, high commercial value of the
land, and air and soil pollution that is detrimental to
plants prevent traditional greening using trees and
lawns in urban environments with high population
density and intensive traffic. Urban photo-bioreactor
LIQUID3 represents an alternative concept of
greening that was developed for such urban
environments. LIQUID3 exploits high efficiency of
microalgae in CO2 fixation and O2 and biomass
production, as well as water column filtration that
removes PM particles from the polluted air. A
multidisciplinary approach was applied to integrate
biotechnological application with urban functions
– bench, USB solar charger, and nightlight, and
contemporary design, which represent the basis
of its functionality and viability in the urban space.
Alternative concepts of greening like LIQUID3 enable
smart use of city space, promote environmental
awareness, and support even distribution of greenery
throughout the city, which is related to economic
prosperity, social justice and sustainability. The
innovative idea of urban photo-bioreactor LIQUID3
has been developed from the concept to the
prototype at the University of Belgrade – Institute
for Multidisciplinary Research with the support of
UNDP Serbia, Global Environmental Facility and the
Ministry of Environmental Protection of the Republic
of Serbia. The prototype was installed in the centre
of Belgrade in September 202
IMPROVED PROPERTIES OF ALTERNATIVE BINDERS AND THEIR POTENTIAL APPLICATION FOR SOIL STABILIZATION
Get PDFThis paper investigates the influence of mechanical activation of different
types of fly ash on the properties of alternative binders – geopolymers based on
alkali activated fly ash. Fly ash was firstly mechanically and then alkali-acti-
vated. Mechanical activation of fly ash was conducted in a planetary ball mill.
Alkali activation of fly ash was carried out at room temperature by use of so-
dium silicate solution as an activator. Structural changes of geopolymers were
assessed by SEM and EDS analysis. Mechanical activation of fly ash led to a
significant increase in strength of these alternative binders, thereby expanding
their potential application, such as soil stabilization