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Reuse of Fly Ash as an Adsorbent for the Removal of Organic and Inorganic Pollutants From Water
No full textLeteći pepeo je glavni industrijski nusproizvod sagorevanja uglja, i predstavlja ekološki izazov,
ali i resurs sa visokim potencijalom za valorizaciju. Tradicionalno odlaganje letećeg pepela na
deponijama narušava kvalitet zemljišta, i dovodi do povećanja rizika od zagađenja životne sredine.
U cilju smanjenja negativnog ekološkog uticaja letećeg pepela u današnje vreme se sve više pažnje
poklanja njegovoj ponovnoj upotrebi u različitim sektorima.
Jedna od najčešćih primena letećeg pepela je u građevinskoj industriji, gde služi kao dodatni
materijal u proizvodnji betona i drugih građevinskih kompozita. Ovakav pristup obezbeđuje značajno
smanjenje količine letećeg pepela na deponijama, kao i dobijanje građevinskih materijala poboljšane
mehaničke čvrstoće, i dugoročne izdržljivosti i otpornosti na hemijsku degradaciju. Ponovno
korišćenje letećeg pepela u proizvodnji građevinskih materijala u skladu je sa principima cirkularne
ekonomije i održivog razvoja.
Pored svoje primene u oblasti građevinarstva, leteći pepeo sve više nalazi primenu u zaštiti
životne sredine, kao adsorbent za uklanjanje zagađujućih materija u tretmanu voda. Zbog svog
hemijskog sastava i porozne strukture, sirovi leteći pepeo pokazuje umereni kapacitet za adsorpciju.
Međutim, različite tehnike modifikacije, kao što su alkalni tretman, hidrotermalna karbonizacija,
hemijska aktivacija, polimerizacija, primenjuju se kako bi se poboljšale adsorpcione osobine letećeg
pepela. Modifikovani leteći pepeo pokazao je značajnu efikasnost u uklanjanju organskih (npr. boje,
pesticidi, farmaceutski proizvodi) i neorganskih (npr. teški metali, arsen) zagađujućih materija iz
otpadnih voda. Ovako dobijeni materijali predstavljaju jeftine i efikasne adsorbente, koji su pogodni
za korišćenje u sistemima za prečišćavanje vode.
Upotreba letećeg pepela u oblasti građevinarstva i kao adosrbenata, ne samo da ublažava
ekološke rizike povezane sa njegovim odlaganjem, već i povećeva isplativost tehnologija za kontrolu
zagađenja životne sredine. Budući napreci u modifikaciji materijala mogu dodatno doprineti
bezbednoj i širokoj primeni letećeg pepela u cilju zaštite životne sredine.Fly ash, a major industrial byproduct of coal combustion, presents both an environmental
concern and a resource with high valorization potential. Traditionally disposed of in landfills, fly ash
contributes to land degradation and pollution risks. However, innovative strategies for its reuse
significantly reduce environmental waste while enabling sustainable solutions across various sectors. One of the most established uses of fly ash is in the construction industry, where it serves as a
supplementary cementitious material in concrete and other building composites. This approach
significantly lowers the environmental impact by reducing the amount of landfilled fly ash and
improves the mechanical strength, long-term durability, and resistance of building materials to
chemical degradation. Incorporating fly ash into construction materials is in line with the principles
of circular economy and sustainable development.
Beyond its structural applications, fly ash is gaining attention for its role in environmental
remediation, particularly in water treatment. Due to its chemical composition and porous structure,
raw fly ash exhibits moderate adsorption capacity. However, various modification techniques, such
as alkaline and hydrothermal treatments, chemical activation, polymerization, and surface coating,
have been employed to enhance the adsorptive properties of fly ash. Modified fly ash has shown
significant efficiency in removing organic (e.g., dyes, pesticides, and pharmaceuticals) and inorganic
(e.g., heavy metals, arsenic) pollutants from wastewater. These modified forms act as low-cost,
efficient adsorbents, suitable for integration into water purification systems.
Utilizing fly ash in these dual roles not only mitigates environmental hazards associated with
its disposal but also increases the cost-effectiveness of technologies applied for pollution control.
Future advancements in material modification and policy frameworks can further promote fly ash's
safe and widespread application in sustainable environmental management.Predavanje po poziv
Development and Optimization of Grape Skin Extract-Loaded Gelatin–Alginate Hydrogels: Assessment of Antioxidant and Antimicrobial Properties
No full textIn this study, we aimed to develop and optimize unique eco-friendly gelatin–alginate hydrogels enriched with sustainable grape skin extract for advanced wound healing applications. Methods: Following confirmation of the extract’s antioxidant activity, hydrogels were synthesized by varying gelatin content and CaCl2 concentration to achieve desirable crosslinking density, mechanical properties, and extract release behavior. Physicochemical characterization of hydrogels included equilibrium swelling analysis, mechanical testing, FTIR analysis, and in vitro release of extract from hydrogel. Moreover, the biocompatibility of hydrogels enriched with extract was assessed via MTT assay, while antimicrobial activity was tested against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, and Candida albicans ATCC 10231. The antioxidant capacity of the hydrogels was evaluated using DPPH, ABTS, and FRAP assays. Results: Our results showed that higher gelatin and CaCl2 concentrations produced denser crosslinked networks, leading to reduced swelling and increased stiffness. Additionally, the extract exhibited a biphasic release profile from hydrogels, featuring an initial rapid release followed by sustained release over 24 h. Conclusions: The hydrogels maintained high biocompatibility and demonstrated selective antimicrobial activity, particularly against Escherichia coli, and satisfactory antioxidant activity. Obtained multifunctional sustainable hydrogels enriched with grape skin extract represent promising agents for managing skin conditions associated with oxidative stress and bacterial infections
Annual Cycle, Abundance and Species Composition of Appendicularia in the Bay of Boka Kotorska (Southern Adriatic, NE Mediterranean)
No full textAppendicularians often constitute a significant portion of mesozooplankton tunicates in marine ecosystems. This study examines the spatial variations in the annual cycles of functional groups of planktonic Appendicularia in response to environmental changes within the Bay of Boka Kotorska. Monthly sampling over the course of a year during 2008/09 was conducted at seven stations, each characterised by distinct hydrographic conditions. Appendicularians exhibited spatial variations in their annual cycles across the seven stations. Based on these findings, it is proposed that the observed spatial variations in the annual cycles of functional groups of planktonic Appendicularia may reflect changes in hydrographic conditions. We present hydrographic data alongside information on the presence, abundance and distribution of eight species of two genera: Oikopleura dioica Fol, O. longicauda Vogt, O.fusiformis Fol, Fritillaria aequatorialis Lohmann, F. megachille Fol, F. pellucida (Busch), F. haplostoma Fol and F. borealis Lohmann. We also provide an overview of the occurrence of the dinoflagellate N. scintillans and its relationship with Appendicularia in the Bay of Boka Kotorska
Separation of xylo-oligosaccharides using ultra- and nanofiltration membranes and investigation of their prebiotic effect
No full textIntroduction: Xylo-oligosaccharides (XOS) are potential prebiotics
composed of xylose units linked by β-(1-4)-xylosidic bonds. In addition to
health benefits, their favourable physicochemical properties and moderate
sweetness make them suitable nutritional ingredients for food and feed
products. Unlike other prebiotics, XOS can be produced from agricultural
and wood residues (corn cobs/stalks, bagasse, rice hulls, birch wood, etc.) by
enzymatic hydrolysis of xylan, the main hemicellulosic part of the mentioned
sources. This strategy, which includes using renewable plant sources as a
source of xylan and enzymes, represents an environmentally friendly process
compared to conventional methods and results in a mixture of XOS of
various degrees of polymerization (DP), unreacted xylan, and
monosaccharide units (xylose). Given that the prebiotic potential of XOS
depends on the DP and purity, this research is focused on applying
membrane separation techniques to obtain a mixture of higher purity and
defined molecular weight with optimal prebiotic activity
Sezonski trendovi u kvalitetu vode i njihove implikacije na tehnologiju prerade u proizvodnji vode za piće
No full textEfikasno upravljanje vodnim resursima nije važno samo zbog njihove osnovne uloge u snabdevanju vodom za piće, već i zbog njihove široke primene u poljoprivredi, industriji i razvoju društvenih zajednica. Ključni korak u očuvanju kvaliteta vode pre njenog tretmana jeste zaštita izvorišta, što podrazumeva kontrolu upotrebe slivnog područja i smanjenje zagađenja iz antropogenih i prirodnih izvora [1, 2]. Reke Dunav, Sava, Tisa i Velika Morava, kao najveći vodotoci u Republici Srbiji, klasifikovane su u II i III klasu kvaliteta voda, što ih čini pogodnim za navodnjavanje i određene industrijske svrhe, ali ne i za korišćenje u svrhe vodosnabdevanja bez prethodne prerade [3]. Sistemi za vodosnabdevanje obuhvataju infrastrukturu za preradu vode, koja služi za uklanjanje zagađujućih materija iz sirove vode, kao i distributivnu infrastrukturu, koja omogućava transport prečišćene vode do domaćinstava i privrednih subjekata [4]. Prisustvo različitih nečistoća u vodi zahteva njeno prečišćavanje do zakonski prihvatljive granice, kako bi se obezbedili higijena i sigurnost pre upotrebe i kako bi bila pogodna za specifične namene. Stoga su sistemi za vodosnabdevanje od suštinskog značaja za društvenu zajednicu [5]. Preduzeće „Beogradski vodovod i kanalizacija“ osnovano je kao javno komunalno preduzeće koje obavlja osnovne delatnosti poput prerade i distribucije vode za piće, odvođenje atmosferskih i upotrebljenih voda, kao i poslove vezane za snabdevanje vodom i njeno kanalisanje. Obuhvata četiri pogona za pripremu higijenski ispravne vode za piće: „Bele vode“, „Banovo brdo“, „Bežanijska kosa“ i „Makiš“ [6]. Proizvodni pogon (PP) „Makiš“ prerađuje površinsku vodu reke Save i obezbeđuje skoro 60% ukupne potražnje za pitkom vodom u gradu Beogradu
Polyphenol-rich strawberry extract as potential modulator of skin microbiota
No full textIntroduction: Enzyme-assisted extraction (EAE) is an efficient method for
obtaining phytochemicals, plant-derived compounds known for their
antioxidant properties. By using enzymes to break down plant cell walls,
EAE enhances the release of these bioactives. Among various sources,
strawberries are particularly rich in polyphenols such as anthocyanins,
flavonoids, and ellagic acid, which are known for their potent antioxidant
activities. Recently, interest has grown in using such extracts to support skin
health, particularly by influencing the skin microbiota - the diverse
community of microorganisms that live on the human skin. Maintaining a
balanced skin microbiome is essential for healthy skin, and phytochemicals
extracted from fruit via EAE offer promising natural solutions to help
regulate and support this delicate ecosystem. Therefore, the aim of this
research is to obtain polyphenol-rich extract from strawberry using EAE and
to evaluate their potential as skin prebiotics
Can the treatment of urea-derived g-C3N4 with H2SO4 be optimized by varying the acid concentration to enhance the efficiency of photocatalytic Cr(VI) reduction?
No full textUrea-derived g-C3N4 (BCN) was treated with H2SO4 at different concentrations: very dilute (0.04 M), dilute (1 M and 4 M) and concentrated, with or without KMnO4. Increasing concentration led to a decrease in specific surface area (Sp), widening of the band gap (BG) and an increase in the acidic group content. Structural reorganization after the dissolution in concentrated H2SO4 led to the formation of much larger particles, especially when KMnO4 was used. These samples had much lower Sp, wider BG, and a large difference in electron-hole recombination rates, which was attributed to different distributions of oxygen-containing groups. Despite the reduction in Sp, the H2SO4-treated samples exhibited a higher efficiency of Cr(VI) reduction under UV than BCN. Conversely, the enlarged BG affected the activity of the modified samples under visible light. The Cr(VI) reduction is dependent on pH during photocatalysis, which decreases as the content and acidity of surface groups increases
Sorption Behavior of Nickel(II) on Natural and Fe(III)-Modified Clinoptilolite: Optimization and Mechanism Insight
No full textThis study evaluates the sorption behavior of natural zeolite (NZ) and Fe(III)-modified
natural zeolite (FeZ) for Ni(II) ions, with the objective of assessing their potential for
application in the remediation of nickel-contaminated environments. Optimization of
sorption parameters, including pHo, solid/liquid ratio (S/L), contact time, and initial
Ni(II) concentration was performed to maximize both the sorption capacity of the zeolites
and the removal efficiency of Ni(II) from suspension. The results demonstrated that both
pHo and S/L ratio exert a significant influence on Ni(II) sorption onto both zeolites, with
a particularly pronounced effect observed for FeZ. Experimental results confirmed that
FeZ exhibits a four-to-five times higher sorption capacity for Ni(II) than NZ, which was
additionally verified by elemental analysis, SEM-EDS, and elemental mapping of Ni(II)-
saturated zeolites. Intraparticle diffusion was identified as the rate-limiting step in the
transfer of Ni(II) ions to the active sorption sites. Ion exchange was identified as the
main sorption mechanism accompanied by outer-sphere complexation and electrostatic
attraction. Leaching tests of Ni(II)-saturated zeolites, conducted in accordance with the
standard DIN 38414 S4 method, demonstrated that both zeolites effectively retained Ni(II)
within their structures over a wide pH range, 4.11 ≤ pHo ≤ 12.02. These findings indicate
the potential applicability of zeolites for remediation of nickel-contaminated environments,
with FeZ being particularly promising due to its enhanced sorption capacity for Ni(II) ions
On the tumor cell growth limiting potential of newly synthesized acridine-1,8-dione derivatives
No full textA series of acridine derivatives, namely 10-(4-substituted benzyl)-9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-tetrahydroacridine-1,8(2H,5H)-diones, was synthesized via the Hantzsch-type multicomponent reaction between dimedone, 4-hydroxybenzaldehyde and 4-substituted benzylamine. The cytotoxic potential of these compounds was evaluated against human ovarian (A2780), melanoma (A375), colon (HCT 116) and breast cancer (MCF-7) cell lines, as well as normal human lung fibroblasts (MRC-5) and keratinocytes (HaCaT). Tested cell lines displayed different but moderate sensitivity to the investigated compounds, with the exception of compounds with a methyl (2) and a bromo group on the benzyl ring (6). These two compounds were almost equally effective against all cancer cell lines tested, suggesting that their activity is more general and less dependent on cell-specific characteristics. Compound 2 showed satisfying solubility, thus appeared to be the most acceptable for further examination and the A375 cell line was selected as the platform for evaluating the compound as the most sensitive to the applied treatment. This compound was shown to induce cell cycle arrest in G2/M phase, accelerating aging manifested through development of differentiated as well as senescent-like phenotype and subsequent fragmentation of genetic material. All aforementioned effects were accompanied with strong increment in production of reactive oxygen/nitrogen species (ROS/RNS). Docking studies against topoisomerase IIβ, hypoxia-inducible factor (HIF) 2α and mitogen-activated extracellular signal-regulated kinase (MEK) 1 revealed that treatment with tested compound might interfere with key signaling pathways involved in cell proliferation, and metabolic features of crucial importance for tumor progression. The obtained results contribute to the expansion of biologically relevant chemical space, thus providing guidelines for the assessment of new candidates for anticancer drugs
Electrophoretically Deposited Composite Hydroxyapatite, Chitosan and Graphene Coatings on Titanium With and Without Gentamicin
No full textCilj ove doktorske disertacije bilo je dobijanje i karakterizacija novih antibakterijskih prevlaka na bazi hidroksiapatita, hitozana i grafena na titanu sa i bez dodatka gentamicina. Prevlake su dobijene postupkom elektroforetskog taloženja u jednom koraku iz stabilnih vodenih suspenzija za primenu u oblasti koštanih implantata.
Detaljna karakterizacija dobijenih prevlaka je rađena u cilju ispitivanja njihove strukture, morfologije i fizičko-hemijskih svojstava, kao i adhezije prevlaka za supstrat. U okviru ovih istraživanja ispitan je i uticaj dodatka grafena na fizičko-hemijska i biološka svojstva dobijenih prevlaka kao i mogućnost inkorporacije gentamicina kao antibakterijskog agensa. In vitro ispitivanja su obuhvatila ispitivanja kinetike otpuštanja gentamicina u fiziološki relevantnim uslovima (37 °C) tokom 21 dana, kao i evaluaciju bioloških svojstava prevlaka, uključujući antibakterijsku aktivnost i biokompatibilnost istaloženih prevlaka.
Rezultati ove disertacije su pokazali da su postupkom elektroforetskog taloženja uspešno istaložene antibakterijske, biokompatibilne kompozitne prevlake na titanu. Inkorporacija grafena doprinela je poboljšanju fizičko-hemijskih svojstava prevlaka, pri čemu je njegova velika specifična površina omogućila efikasnije vezivanje i ugrađivanje veće količine antibiotika. Količina inkorporiranog antibiotika bila je dovoljna za postizanje izraženog antibakterijskog efekta izazivajući potpunu redukciju ukupnog broja ćelija soja S. aureus, pri čemu nije ispoljena citotoksičnost prema humanim ćelijskim linijama (MRC-5) u in vitro uslovima. Biomineralizacija prevlaka potvrđena je formiranjem novog sloja apatita na njihovoj površini, već nakon sedam dana izlaganja simuliranoj telesnoj tečnosti. Na osnovu dobijenih rezultata, može se zaključiti da ovi materijali poseduju visok potencijal za dalja istraživanja i primenu u ortopediji i regenerativnoj medicini.The aim of this doctoral dissertation was the development and characterization of novel
antibacterial coatings based on hydroxyapatite, chitosan, and graphene on titanium, with and without
the addition of gentamicin. The coatings were produced by a one-step electrophoretic deposition
process from stable aqueous suspensions, intended for application in the field of bone implants.
Detailed characterization of the obtained coatings was conducted to investigate their structure,
morphology, physicochemical properties, and adhesion to the substrate. The influence of graphene
addition on the physicochemical and biological properties of the coatings was also examined, as well
as the potential for incorporating gentamicin as an antibacterial agent. In vitro studies included the
investigation of gentamicin release kinetics under physiologically relevant conditions (37 °C) over a
period of 21 days, as well as the evaluation of the biological properties of the coatings, including
antibacterial activity and biocompatibility of the coatings.
The results of this dissertation demonstrated that antibacterial and biocompatible composite
coatings were successfully deposited on titanium using the electrophoretic deposition technique. The
incorporation of graphene contributed to improved physicochemical properties of the coatings, with
its high specific surface area enabling more efficient binding and retention of larger amounts of the
antibiotic. The amount of incorporated antibiotic was sufficient to achieve a pronounced antibacterial
effect, resulting in complete reduction of the total number of S. aureus cells, without exhibiting
cytotoxicity toward human cell lines (MRC-5) under in vitro conditions. The bioactivity of the
coatings was confirmed by the formation of a new apatite layer on their surface after only seven days
of exposure to simulated body fluid. Based on the obtained results, it can be concluded that these
materials possess high potential for further research and application in orthopedics and regenerative
medicine