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Conversion of Tree Leaf Biowaste into a Promising Material as Energy source
No full textThis study investigates the conversion of Paulownia tree leaf biomass (LP) into biochar (BLP) through slow pyrolysis at 400 °C under low-oxygen conditions. The research aims to elucidate the influence of the pyrolysis process on the chemical composition, structural characteristics, and combustion behavior of the resulting biochar. Thermogravimetric and Differential Thermal Analysis (TG/DTA), along with proximate and elemental analyses, were employed to provide comprehensive insights into the physicochemical and thermal properties of the biochar, which are crucial for assessing its potential as an energy material. The process yielded a significant increase in fixed carbon (from 8.72 ± 0.23% to 41.96 ± 0.28%) and total carbon content (from 45.49 ± 0.21% to 64.11 ± 0.42%), accompanied by a marked decrease in oxygen content (from 38.05 ± 0,09% to 9.68 ± 0.01%), resulting in a reduced O/C ratio (from 0.63 to 0.11). The higher heating value increased from 18.98 MJ/kg to 26.44MJ/kg, with improvements in fuel ratio (FR) and lower heating value (LHV), collectively enhancing the biochar’s energy potential. Thermal analysis confirmed the formation of new aromatic structures, reflecting enhanced thermal stability and improved combustion characteristics. Overall, Paulownia leaves represent a promising biomass feedstock for sustainable biochar production, contributing to waste valorization, pollution mitigation, and the development of alternative energy resources
Monitoring Heavy Metal Mobilisation in Acid Leaching of Coal
No full textAcid leaching was applied to coal samples from the Bogovina basin, located in eastern Serbia, in order to evaluate its effectiveness in reducing sulphur and ash content and to monitor the mobilisation of heavy metals into the leachate. The experiments were conducted under controlled laboratory conditions, with a leaching time of 30 minutes, employing three different temperatures and various acid concentrations. Two acid reagents were tested, and the resulting leachates were analysed for concentrations of heavy metals, including Cr, Cu, Co, and Pb.
The analytical results, obtained using an Atomic Absorption Spectrophotometer (AAS) and Eschka method, showed that acid leaching significantly reduced the sulphur and ash content of the coal while simultaneously mobilising varying amounts of heavy metals into the aqueous phase. The extent of metal mobilisation depended on the type of acid used, indicating that reagent composition plays a key role in determining both desulphurisation efficiency and environmental impact.
This study confirms the presence of toxic heavy metals in coal from the Bogovina region and demonstrates that acid leaching can effectively improve coal quality, although it may increase the mobility of certain metals. These findings highlight the need to balance coal upgrading with appropriate management in order to minimise environmental risks.
Future research will focus on comparing the concentrations and behavior of heavy metals in leachate and sediments from the Bogovina area, to gain a deeper understand of metal distribution and potential pathways within the local environment
High-Temperature Nanoindentation Behavior of Single-Crystalline Titanium: A Molecular Dynamics Study
No full textThe mechanical responses of the single-crystalline hexagonal close-packed (HCP) metals, such as
titanium (Ti), make them highly valuable for applications requiring excellent strength-to-weight ratios
and high-temperature stability. Titanium's ability to maintain mechanical performance at elevated
temperatures (600–1300 K) has been observed through nanoindentation experiments. Obtained
results of the local hardness and elastic modulus values, i.e. nanoindentation behaviour at elevated
temperature, reveal the connection of dislocation mechanisms and defect nucleation. The main focus
of this work is a computational study of the high temperature effects on the mechanical deformation
properties of a single-crystalline Ti during a nanoindentation test. Molecular dynamics (MD)
simulations of a spherical nanoindentation are carried out at two indenter tip diameters and crystalline
sample orientations [001], [10-10], and [11-20], for a temperature range of 10–1000 K. The study
examines how the temperature increacment affects the nanoindentation process, altering dislocation
densities, slip mechanisms, atomic displacements, and the local hardness, as well as its agreement with
experimental finding
Application of Thermogravimetric analysis on combustion study of biomass for Zn extraction
No full textForage sorghum (Sorghum spp.), recognized among the world most important cereal crops
characterized with high biomass yield. Varieties of sorghum are able to uptake Zn from
different types of polluted soils, while exhibiting high biomass production and
effectiveness in phytoremediation. Considering increased metal concentrations in the plant
biomass it is possible to develop an economically viable method for recovering heavy
metals, including Zn. One of the key stages in developing an optimal Zn-recovery method
is optimization of combustion temperature, to avoid potential loss of Zn due to
volatilization. When investigating the combustion of sweet sorghum researhers found that
it is comprised of two different thermal stages, pyrolysis and char oxidation. [1]
Comprehensive studies have demonstrated the validity of using TGA in combination with
other analytical methods when investigating the combustion of biomass. [2] Three different
times were investigated in this study at four different temperatures (400 ºC, 450 ºC, 500 ºC,
600 ºC). This low temperature range and operational conditions of combustion are
convinient, since studies that also employ thermal analyisis thehniques have shown what
can happen to ash after incineration and how the fusing of ash particles can result in
slagging, fouling and corrosion within the furnace. However, other studies have shown that
combustion ashes chemical compositions are strongly influenced by the feedstock's plant
taxonomy, particularly if the feedstock belongs to woody or herbaceous plants. [3] Forage
sorghum's (Sorghum spp.) potential for phytoextractions of contaminated dredged
sediment in a real environment and authentic natural conditions was investigated,
producing harvested biomass enriched with Zn. Combustion time and temperature were
varied to see which combination would yield the highest concentration of Zn in the
leftover ash. The starting mass of the plant sample was in the range between 30 and 50g
and with the mass loss of around 90% the highest Zn content was found after combustion
of 6h at 500 C
Granulati brašna od tropa voća i povrća sa prebioticima i bakterijama mlečne kiseline
No full textPronalazak se odnosi na postupak dobijanja granulata i
obogaćenih granulata brašna od tropa voća i povrća čime
se poboljšavaju nutritivna svojstva i fizičke osobine
brašna. Mokrom granulacijom se na brašno u
fluidizovanom sloju, koje može biti dodatno obogaćeno
dijetnim vlaknima sa prebiotskim dejstvom u udelu 1-
20%, na 35-55 °С naprskava vezivno sredstvo. Kao
vezivno sredstvo mogu biti korišćeni 1-20% rastvori
mono-, di-, oligo- ili polisaharida sa i bez dodatka
probiotskih kultura ili startera. Nakon granulacije se pri
30-40% nižem pritisku sprovodi sušenje. Niska aktivnost
vode (0,15-0,40) i visoka temperatura staklastog prelaza
(31-43 °С) potvrđuju trajnost granulata i njihovu
stabilnost na sobnoj temperaturi. Snižen Carr-ov indeks
(do 60%) i Hausner-ov odnos (do 30%) ukazuju na
poboljšanje protočnosti. Dobijene granulate karakteriše
visok sadržaj DV, prebiotski, probiotski ili simbiotski
efekat, i produžena vijabilnost imobilisanih sojeva. Oni
se mogu primeniti kao dodatak ishrani ili premiks za
fermentisane proizvode
Impact of Recrystallization on the Purity of ANSH Crystals Produced from Ni Hyperaccumulator Plant
No full textThe industrial development will influence the demand and price of nickel in the coming years which opens the possibility for the use of innovative ways for its exploitation from secondary resources. Phytomining of nickel is a prospective in situ technology that uses plants with natural hyperaccumulating capabilities for this element. This study represents application of currently established and developed hydrometallurgical methods on wild populations of nickel hyperaccumulator from Serbia and explores the impact of recrystallization on the purity of the final product. The study confirms that nickel salts (ammonium nickel sulfate hexahydrate) can be synthesized from the Odontarrhena muralis that is naturally occurring on the ultramafic sites in West Serbia. Due to the small starting mass for the harvested biomass the preliminary experiments were separated into two series, which yielded 7,3g and 5,2g nickel salts of 60% and 73% purity, respectively, before recrystallization. However after recrystallization their purity was maximized reaching analytical levels of purity 99,9%, whereas their mass was reduced to 5,45g and 3,89g. More comprehensive studies with larger biomass and proper cultivation on ultramafic soil are needed in future to fully explore the potential for the development of Ni phytomining in Serbia
Specifičnosti baterija za automobile i njihov uticaj na životnu sredinu
No full textZa razumevanje zaštite životne sredine je ključan multidisciplinarni pristup
ovoj problematici, kao i rešavanje kompleksnih ekoloških problema. Ovaj pristup uključuje
saradnju različitih disciplina kao što su biologija, ekologija, sociologija, ekonomija, politika
i mnoge druge. Ključni elementi multidisciplinarnog pristupa su integracija znanja iz
različitih disciplina kako bi se stvorila celovita slika ekoloških izazova. Saradnja između
različitih strana, uključujući vladu, industriju, naučne institucije i civilno društvo je ključno
za zdrav pristup životnoj zajednici i njenom očuvanju i poboljšanju.
Razmatranje životne sredine kao kompleksnog sistema gde svaki deo utiče na celinu je
od izuzetnog značaja, dok primena principa održivosti pomaže kako bi se osiguralo da se
potrebe današnjih generacija zadovolje bez ugrožavanja mogućnosti budućih generacija.
Ovaj pristup omogućava bolje razumevanje i rešavanje problema poput klimatskih promena,
degradacije zemljišta, izumiranja vrsta i zagađivanja vode.
Automobilska industrija doprinosi zagadjenju životne sredine na nekoliko načina i zbog
toga je bitno razmotriti koji su to izvori energije koji bi se primenili kao pogonska snaga
automobila najefikasniji i pritom najmanje opterećuju i ovako veoma zagađenu životnu
sredinu. U ovom radu su analizirani elementarni pokazatelji različitih izvora energije, odnosno baterija koje služe kao pogon automobila, i to fosilna goriva, litijumske baterije,
natrujumske baterije i vodonik kao pogonsko gorivo za automobile.
U cilju postavljanja komparacija uticaja različitih izvora energije za motorna vozila,
može se postaviti zaključak da motori na fosilni pogon imaju visoka energetska gustina, široka
dostupnost, ali produkuju emisiju štetnih gasova kao što su ugljen-dioksid (CO2), azotni
oksidi (NOx), sumpor-dioksid (SO2) i isparljiva organska jedinjenja (VOC), što doprinosi
zagađenju vazduha, efekatu staklene bašte i zdravstvenim problemima.
Litijumske baterije imaju visoku energetsku gustinu, dug vek trajanja, široka primena
u elektronici i električnim vozilima, ali je ekstrakcija litijuma veoma ekološki štetna, uključujući
zagađenje vode i zemljišta. Sama proizvodnja litijumskih baterija zahteva velike
količine vode i energije.
Natrijumske baterije su znatno jeftinije, dostupnije, manje štetne za životnu sredinu.
Natrijum je mnogo rasprostranjeniji od litijuma, što smanjuje ekološki otisak ekstrakcije.
Ipak, ove bateije imaju nižu energetsku gustinu u poređenju sa litijumskim baterijama, što
ih čini težim i glomaznijim.
Vodonikove baterije proizvode samo vodu kao nusproizvod, što ih čini ekološki najprihvatljivijim.
Mogu se koristiti za skladištenje energije iz obnovljivih izvora. Nedostaci
primene vodinika kao goriva su, za sada, visoki troškovi proizvodnje i skladištenja vodonika,
kao i potreba za infrastrukturom za distribuciju.
Svaka tehnologija ima svoje prednosti i nedostatke, ali natrijumske baterije trenutno
izgledaju kao najodrživija alternativa litijumskim baterijama zbog nižeg ekološkog otiska
i veće dostupnosti resursa
Adsorption of Cd(II) ions using immobilized oat straw modified with a deep eutectic solvent: kinetic and structural insights
No full textThe present study provides a potential use of waste biomass, oat straw (ST), as an efficient adsorbent in the removal of heavy metals from aqueous solutions. ST was modified with the selected deep eutectic solvent (DES) to enhance its adsorption capacity and obtain a structure-altered material (DST). Additional functionalization was done by immobilizing the modified biomass (DST) in alginate beads (IDST) to improve handling and applicability in realistic water treatment systems.
The adsorption studies were performed in a batch system to investigate the removal of Cd(II) ions from water by native, modified, and immobilized oat straw. It could be seen that the adsorption capacity increased significantly after DES modification and immobilization. The maximum adsorption capacities were 20.4, 49.41, and 89.87 mg/g for ST, DST, and IDST, respectively. The kinetic investigation demonstrated that the adsorption behavior agreed with a pseudo-second-order model, indicating that the adsorption of Cd(II) ions on adsorbents was driven by chemisorption.
Consistent with the enhanced adsorption efficiency scanning electron microscopy SEM presented the direct evidence of morphology changes caused by DES treatment. These results suggest that the DES-modified biomass can be sustainably and effectively used for the removal of heavy metal ions, and therefore could afford environmentally benign and cost-effective purification strategies on aqueous solutions
Synthesis and application of FeMg-modified hydrochar for efficient removal of lead ions from aqueous solution
No full textThis study explores the utilization of waste grape pomace-derived hydrochar as an efficient
adsorbent for lead (Pb2+) removal from aqueous solutions. Hydrochar was produced via
hydrothermal carbonization (HTC) at 220 ◦C, followed by doping with magnesium and
iron salts, and subsequent pyrolysis at 300 ◦C to obtain Fe/Mg-pyro-hydrochar (FeMgPHC). The material’s structural and morphological changes after Pb2+ adsorption were
examined using FTIR. FTIR revealed chemisorption and ion exchange as key mechanisms,
shown by decreased hydroxyl, carbonyl, and metal–oxygen peaks after Pb2+ adsorption.
Adsorption tests under varying pH, contact time, and initial Pb2+ concentrations revealed
optimal removal at pH 5. Kinetic modeling indicated that the process follows a pseudosecond-order model, suggesting chemisorption as the dominant mechanism. Isotherm
analysis showed that the Sips model best describes the equilibrium, with a maximum
theoretical adsorption capacity of 157.24 mg/g. Overall, the simple two-step synthesis—
HTC followed by pyrolysis—combined with metal doping yields a highly effective and
sustainable adsorbent for Pb2+ ion removal from wastewater
Geological and technological characteristics of the Igroš- Vidojevići zeolite tuff deposits
No full textIn this work presents investigations of zeolitic tuff samples from the “Igroš-Vidojevići” deposit. The aim of
the research was to determine the quality of samples taken from all deposit parts. Thus, samples were taken
from the footwall (“Zeolit 1”), and four samples from the central deposit part (“Zeolit 2”, “Zeolit 3”,
“Zeolit 4” and “Zeolit 5”). Characterization of the samples included chemical analysis, determination
cation-exchange capacity (CEC), X-ray powder diffraction analysis (XRPD) and differ- ential thermal and
thermogravimetric analysis (DTA and TGA). Results have shown that the footwall consists mostly of clays,
whereas zeolite minerals dominate in the rest of the deposit