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Evaluation of eco-friendly porous ceramics for removal of Zn2+ ion from aqueous solutions: Kinetic, equilibrium and thermodynamic studies
No full textIn the last decade, access to clean water has become a challenge, because of the rapid population growth and
enormous agricultural and industrial activities. There are numerous processes for removing dissolved heavy
metals, including ion exchange, coagulation, precipitation and adsorption. Adsorption could be the most
effective for this purpose because of the low cost, easy operation, and short duration time. Nowadays, porous
ceramic materials are promising adsorbents for different heavy metal ions. Eco-friendly porous ceramics
based on natural zeolite and bentonite clay were synthesized and adsorption capacity toward Zn2+ ions was
investigated. The synthesis was performed using the foaming method without an organic binder. Hydrogen
peroxide was used as the blowing agent, while sodium dodecyl sulfate was used as the foaming agent. The
obtained green and sintered samples of porous ceramics were characterized in detail by different methods
(TG/DTG, SEM, XRD, FTIR, XRF). Results showed that the foamed samples could be synthesized at room
temperature and fully crystallized after being sintered at 800 °C. Total porosity of porous ceramic sample
reached maximum value of 74.7%. The second-order model and Langmuir model best described the
adsorption kinetic and isotherm data. The maximum adsorption capacity obtained using the Langmuir model
was approximately 5.01 mg Zn2+/g. The thermodynamic parameters showed that adsorption is a spontaneous
and endothermic process favored at higher temperatures. Overall, this study highlights the potential of
porous ceramics based on natural zeolite and bentonite for the removal of heavy metals and provides insight
into the mechanisms of the adsorption process
New approaches and applications of natural zeolites for boron adsorption from aqueous solutions
No full textExcessive mineral extraction and boric acid production can lead to elevated boron concentrations in
wastewater. While boron is an essential micronutrient for humans, excessive exposure and intake can result
in adverse health effects. Existing treatment processes for boron contaminated wastewater have various
limitations related to effectiveness, production of additional solid waste and high operational costs. This
study investigates the use of natural zeolite as a cost-effective, sustainable and environmentally friendly
adsorbent for boron removal. Natural zeolites are alumosilicate porous minerals widely used in wastewater
treatment applications. To enhance its adsorption properties, natural zeolite was modified using a nickel
sulphate solution. In this work, four adsorbents were analyzed: raw natural zeolite, nickel-modified natural
zeolite,
zeolite/hydroxyapatite
and
nickel-modified
zeolite/hydroxyapatite
composite.
The
zeolite/hydroxyapatite composite was synthesized under hydrothermal conditions at 160 C for 4 hours at
autogenous pressure. Characterization of the adsorbents was performed using X-ray powder diffraction
(XRPD), scanning electron microscopy and thermogravimetric analysis. XRPD analysis confirmed
clinoptilolite as the dominant mineral phase in the zeolitic tuff and showed that hydrothermal treatment did
not affect its crystallinity. The adsorption properties were tested using a synthetic boron solution at pH 9,
where boron exists in both B(OH)3 and B(OH)4– forms. The results showed that the presence of nickel
primarily on the surface of the adsorbent leads to an increase in boron adsorption, which is a consequence of
its ability to form complexes with B(OH)4–. This research confirmed that adsorbents based on metal
saturated natural zeolite are promising adsorbents of boron compounds from wastewater
Razvoj nove platforme na bazi alginata i aktivnog uglja za lokalnu primenu u terapiji rana
No full textAntibiotska rezistencija je jedan od najvećih kliničkih problema današnjice i ozbiljna pretnja javnom zdravlju. Razvoj novih antibiotika ide sporo i hitno je potrebno razvijati nove strategije za rešavanje ovog problema. Cilj ovog rada bio je razvoj novih antimikrobnih kompozita na bazi hidrogelova, Ca- ili Zn-alginata, i čestica aktivnog uglja (AU) koji bi tokom vremena lokalno oslobađali najmanje jedan bioaktivni agens direktno u predeo rane. Pored toga, AU čestice mogu služiti kao nosači drugih aktivnih supstanci, a kao model supstanca korišćen je povidon jod (PVP-I). Kompoziti Ca- i Zn alginata sa česticama AU impregniranim PVP-I su ispitani u in vitro uslovima u pogledu njihove antimikrobne aktivnosti u kulturama rezistentnih mikroorganizama (MRSA, E. coli, P. aeruginosa, A. baumannii, P. mirabilis, E. faecalis, C. albicans) izolovanih od rana pacijenata. Takođe, kompoziti su okarakterisani u pogledu morfologije, profila oslobađanja AU čestica i Zn2+ jona kao i nivoa adsorpcije i desorpcije joda iz AU čestica. Dobijeni kompoziti su pokazali odličnu antimikrobnu aktivnost. Konkretno, sinergistička aktivnost AU čestica i adsorbovanog joda pokazala se ključnom za efikasnu antibakterijsku aktivnost, dok se sinergija čestica AU i jona Zn2+ pokazala ključnom za efikasno antifungalno dejstvo. Međutim, joni Zn2+ su se pokazali kao selektori rezistentnih sojeva bakterija što bi mogli biti od značaja u svakodnevnom životu, jer se jedinjenja Zn široko koriste od najranijeg uzrasta u kremama i preparatima za kožu. Takođe, pokazano je da je PVP-I čvrsto adsorbovan na česticama AU i da je njegovo oslobađanje u okolnom medijumu zanemarljivo, što je veoma važno iz perspective sprečavanja sistemske apsorpcije joda nakon njegove produžene medicinske upotrebe. Prikazana strategija omogućava dalji razvoj efikasnih multifunkcionalnih obloga za rane sa produženim oslobađanjem jednog ili više potentnih bioaktivnih agenasa in situ u cilju prevencije i lokalne terapije rezistentnih infekcija
Poly(Methyl Methacrylate)-Based Core-Shell Electrospun Fibers: Structural and Morphological Analysis
No full textDicyclopentadiene (DCPD)–poly(methyl methacrylate) (PMMA) core–shell fibers were fabricated via coaxial electrospinning to develop a self-healing polymer composite. A PMMA shell containing a first-generation Grubbs catalyst was co-spun with a DCPD core at 0.5 mL h−1 and 28 kV, yielding smooth, cylindrical fibers. The diameter range of nanofibers was 300–900 nm, with 95% below 800 nm, as confirmed by FESEM image analysis. FTIR spectroscopy monitored shell integrity via the PMMA C=O stretch and core polymerization via the trans-C=C bands. The high presence of the 970 cm−1 band in the healed nanofiber mat and the minor appearance in the uncut core–shell mat demonstrated successful DCPD polymerization mostly where the intended damage was. The optical clarity of PMMA enabled the direct monitoring of healing progress via optical microscopy. The presented findings demonstrate that PMMA can retain a liquid active core and catalyst to form a polymer layer on a damaged site and could be used as a model material for other self-healing systems that require healing monitoring
Non-carcinogenic risk assessment for heavy metals in soils near the thermal power plant
No full textSoil is a vital and dynamic component of the ecosystem, essential for environmental sustainability and socio-economic development; it supports agriculture, food security, water filtration, carbon sequestration, climate regulation, infrastructure, biodiversity, and raw material supply [1]. Population growth, urbanization, and economic expansion drive environmental issues locally, regionally, and globally. Coal combustion in thermal power plants generates significant amounts of ash and represent a major local source of inorganic pollution, releasing pollutants into the air, water, and soil. The long-range transported contaminants and their continuous accumulation accelerates soil deterioration, compromising crop quality and food safety [2]. Increased mobility and bioavailability of metals often lead to excessive accumulation, posing serious environmental and public health risks due to their persistence and toxicity [3]. The hazard quotient (HQ) and hazard index (HI) are used for determination of the impact of heavy metals from soil on noncarcinogenic effects in humans. The present study aims to quantify the concentrations of heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn) in soils across different land uses around the thermal power plant Kostolac and asess the potential health risks for residents from major inorganic contaminants. The research was conducted within the territory of the town Kostolac which is located on the right bank of the Danube in eastern Serbia. This region, with its lignite reserves
and thermal power plants (units A and B), plays an important role in the power production of the country, contributing around 11% of total electricity generation. Soil samples were collected during the autumn of 2023, from 23 sampling points, covering the investigated area of approximately 5-10 km² around the power plant. Surface soils (0-30 cm) were taken from agricultural fields, meadows, orchards, gardens, lawns near the marina and private airport, in close proximity to thermal power plant complex, fly-ash landfill, the archeological site of Viminacium, and near the exploitation field
of natural gas. The sampling area is located between latitudes 44⁰41'53.02788'' – 44⁰44' 9.67'' and longitudes 21⁰9'9.47''– 21⁰10'18.64''. The soils samples underwent a series of preparation steps, including drying, homogenization using a mortar and pestle, and sieving. About 0.45 g of pre-dried soil samples were digested using a SpeedWave XPERT (Berghof) digester according to EPA method 3050B. The heavy metal content was determined in each sample using ICP-MS (iCAP Qc, Thermo Scientific, UK). The results are expressed in mg/kg. Although HI values were generally
higher for children than adults, the highest values for both groups were observed for As and Pb, but still below 1, which is unlikely to pose the non-carcinogenic health risk. To differentiate HI for individual sources, the total hazard index (THI) was used as a comprehensive measure, which represents the sum of hazard quotients for each metal across all three exposure pathways and for all pollutants within a single sample. The THI values were especially high for children (<1) at two sampling sites, S18 (near the power plant, unit B) and S20 (near the fly-ash landfill), suggesting a potential non-carcinogenic health risk from heavy metals
Special Issue "Application of Traditional and Innovative Technologies for the Extraction of Biologically Active Compounds from Natural Food Resources"
No full textThis Special Issue focuses on the latest advancements in extraction technologies aimed at recovering biologically active compounds from natural resources. Both conventional and modern extraction methods are welcomed, with technologies of interest including, but not limited to, the following: Conventional Methods: cold pressing, maceration, percolation, Soxhlet-assisted extraction, and hydrodistillation; Modern Methods: microwave extraction, ultrasound-assisted extraction, accelerated solvent extraction, supercritical CO2 extraction, deep eutectic solvent extraction, pulsed electric field extraction, ionic liquid extraction, and subcritical water extraction. The primary focus will be on natural food resources such as plants, but alternative food sources like insects, marine-derived resources, or wastes from food industry will also be considered.
We invite research contributions where extraction is performed with the goal of producing valuable extracts rich in biologically active compounds, such as phenolics, flavonoids, tocopherols, and chlorophylls. Additionally, the biological activity of these extracts should be examined through at least one assay, such as antioxidant, antimicrobial, antiviral, or cytotoxicity tests. Please note that the results of docking analyses used for antiviral activity screening should be supported by in vitro tests. It would be appreciated if there was a correlation between different extraction procedures and the observed biological activity.
This Special Issue seeks to bring together novel insights into the application of both established and emerging extraction technologies, aiming to enhance the quality, safety, and sustainability of food products.Stoja Milovanović was a guest editor with Ivana Lukić, Agnieszka Grzegorczyk, and Łukasz Świątek for the Special Issue "Application of Traditional and Innovative Technologies for the Extraction of Biologically Active Compounds from Natural Food Resources" of the Foods journal (ISSN 2304-8158) from 05.11.2024 to 31.12.2025. This special issue belongs to the section "Food Engineering and Technology".
Link: https://www.mdpi.com/journal/foods/special_issues/C913R34XT
Preparation of Magnetic Surface Molecularly Imprinting Polymers Based on Glycidyl Methacrylate as Selective Sorbents for Aniline Removal from Aqueous Medium
No full textIn this paper, two molecularly imprinted polymers (MIPs) based on glycidyl
methacrylate were synthesized by radical suspension polymerization and surface imprinting
method in the presence of silica-coated magnetic nanoparticles. Ethylenediamine (eda) and
triethylentetramine (teta) were used for surface imprinting. The samples were characterized
by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with
energy-dispersive X-ray spectroscopy (SEM-EDS), and mercury porosimetry. The sorption
and desorption behaviors of two MIPs as an aniline sorbent from aqueous solutions were
evaluated. Sorption studies were carried out in the pH range of 2.0 - 10.0 and maximum
sorption capacities were attained at pH 6.0. Also, the effect of different desorption agents
were examined and acetonitrile was chosen as the best desorbing eluent for aniline. The
obtained MIPs were regenerated in four sorption/desorption cycles, and the results show that
these two MIPs could be reusable as sorbents for removing aniline from polluted wastewater.У овом раду, два молекуларно утиснута полимера (МИП) на бази глицидилметакрилата синтетисана су методом суспензионе полимеризације преко слободних
радикала и површинског отиска у присуству магнетних обложених наночестица.
Етилендиамин (ЕДА) и триетилентетрамин (ТЕТА) су коришћени за површинско
утискивање. Узорци су окарактерисани инфрацрвеном спектроскопијом са Фуријеовом
трансформацијом, скенирајућом електронском микроскопијом са енергетски
дисперзивном спектроскопијом и методом живине порозиметрије. Испитана је
сорпција и десорпција два МИП-а као сорбента за уклањање анилина из водених
раствора. Сорпција је испитана у опсегу вредности од 2,0 до 10,0 и максимални
сорпциони капацитети су постигнути при pH 6,0. Такође, испитивано је дејство
различитих средстава за десорпцију и ацетонитрил је изабран као најбољи елуент за
десорпцију анилина. МИП-ови су регенерисани у четири циклуса сорпција/десорпција и
резултати показују да се две врсте добијених МИП-ова могу поново користити као
сорбенти за уклањање анилина из отпадних вода
Beyond Food Processing: How Can We Sustainably Use Plant-Based Residues?
No full textPlant-based residues generated within the agri-food system represent an abundant resource with significant potential for sustainable valorization. However, they are still underutilized and place a substantial burden on the environment and climate. This review discusses research trends over the past decade, combining bibliometric analysis with an overview of emerging technologies applied to the processing of residues generated from conventional crops and medicinal and aromatic plants. The bibliometric analysis reveals main valorization pathways, ranging from energy production to recovery of high-value bioactive compounds. Recent advances in this field are discussed in detail, with emphasis on low-energy and non-thermal processing (ultrasound, microwave, cold plasma), green solvents (natural deep eutectic solvents, bio-based solvents), biological pretreatments (with ligninolytic microorganisms and enzymes), thermochemical technologies (hydrothermal carbonization, pyrolysis), and emerging cascade strategies applied for multi-product recovery. Published research proves that these approaches have a great potential for sustainable valorization, while process optimization and economic feasibility remain a challenge at industrial scales for wider adoption. By providing an integrated perspective on diverse types of plant-based residues, this review highlights the importance of developing cascade and circular processing strategies, which align with global sustainability goals and encourage innovation in bio-based industries. New knowledge and advances in this field are highly required and will further help the transition of the current agri-food system towards greater circularity and sustainability
Novel Approach to the Surface Degradation Assessment of 42CrMo4 Steel in Marine and Cavitation Erosion Environments
No full textThis study focuses on the susceptibility and surface degradation of low-alloy carbon steel 42CrMo4 to corrosion and cavitation erosion, as this steel is widely used in marine environments with aggressive chemical species and harsh conditions. Due to its high strength and fatigue resistance, 42CrMo4 steel is often employed in offshore mechanical components such as shafts and fasteners as well as crane parts in ports and harbors. Various experimental methods, including corrosion and cavitation tests, were used to assess the steel’s surface integrity under extreme conditions. Surface changes were monitored using modern analytical tools for precise assessments, including image and morphological analyses, to quantify degradation levels and specific parameters of defects induced by corrosion and cavitation. Non-destructive techniques such as optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and image analysis software were employed for the quantitative assessment of morphological parameters and elemental analysis. EDS analysis revealed changes in elemental composition, indicating corrosion products that caused significant mass loss and defect formation, with degradation increasing over time. The average corrosion rate of 42CrMo4 steel in a 3.5% NaCl solution reached a peak value of 0.846 mm/year after 120 days of exposure. Cavitation erosion behavior was measured based on mass loss, indicating the occurrence of different cavitation periods, with the steady-state period achieved after 60 min. The number of formed pits increased until 120 min, after which it decreased slightly. This indicates that a time frame of 120 min was identified as significant for changes in the mechanism of pit formation. Specifically, up to 120 min, pit formation was the dominant mechanism of cavitation erosion, while after that, as the number of pits slightly declined, the growth and merging of formed pits became the dominant mechanism. The cavitation erosion tests showed mass loss and mechanical damage, characterized by the formation of pits and cavities. The findings indicate that the levels of surface degradation were higher for corrosion than for cavitation. The presented approach also provides an assessment of the degradation mechanisms of 42CrMo4 steel exposed to corrosive and cavitation conditions
Synergistic Effects of Genipin and Alendronate in 3D-Bioprinted Gelatin-Polyvinylpyrrolidone Scaffolds
No full textIn this study, we introduce a one-step semi-solid extrusion 3D printing strategy to fabricate gelatin-polyvinylpyrrolidone (GAG-PVP) scaffolds loaded with a low dose (0.5 wt%) of alendronate (ALN) and crosslinked in situ with 1 wt% genipin. The genipin-crosslinked ALN scaffold (GAG-PVP-GEN-ALN) demonstrated enhanced functional performance compared to both non-crosslinked GAG-PVP and GAG-PVP-ALN controls. Its peak swelling reached 462% at 5 h, surpassing the 362% of the unmodified scaffold and preventing the rapid dissolution observed for GAG-PVP-ALN, before gradually deswelling for 96 h. Water contact angle measurements confirmed that genipin fully restored surface hydrophobicity (101.9°), counteracting the pronounced wettability induced by ALN (47.8°) and exceeding the 78.2° of the GAG-PVP matrix, which is consistent with swelling ratio. Differential scanning calorimetry (DSC) indicated enhanced thermal stability of the crosslinked gelatin, with shifts in both glass transition and denaturation temperatures reflecting greater molecular rigidity despite the presence of glycerol as a plasticizer. Mechanical testing showed that while alendronate alone reduced mechanical performance, the combined inclusion of alendronate and genipin significantly enhanced scaffold properties compared to gelatin-polyvinyl pyrrolidone blend: tensile strength increased from 19.7 MPa to 39.8 MPa, elastic modulus rose from 805 MPa to 1174 MPa, and microhardness improved from 9.24 MPa to 22.3 MPa, values nearing those of native cancellous bone. The sustained ALN release profile extended from an abrupt 3 h burst in GAG-PVP-ALN to a controlled 48 h delivery in GAG-PVP-GEN-ALN, following first-order kinetics. Both direct and indirect cytotoxicity assays confirmed high cell viability (> 85%) without morphological abnormalities. These results highlight that embedding low-dose ALN within a genipin-crosslinked gelatin-PVP network results in a mechanically robust, biocompatible scaffold with tunable swelling and prolonged drug release, offering a versatile platform for localized bone tissue engineering