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Microplastic sources, reduction and remediation: current state and future trends
No full textPlastic waste (PW) and microplastics (MPs) pollution represent one of the main ecological challenges and thus attract society's increasing attention. The exponential growth of plastics' presence and its small (1 μm – 5 mm) particles (MPs) in the environment and inhabiting species is a consequence of linear economy employment. The circular economy has been proposed as the promising route to using plastics more sustainably, and its implementation in the plastic management system is imposed to reduce MPs release. As MPs are emitted in all phases of the plastic life cycle, actions at all levels of the value chain are necessary. Prioritizing the entire plastic value chain also became the goal of more recent plastic pollution regulations, contrary to the previous ones, primarily prohibiting particular plastic items. The microplastic minimization strategy follows an upside-down pyramid, beginning with prevention, then reducing, reusing, recycling, recovering, and finally disposal, which is the least desired alternative. New technologies development for synthetic polymer production and remediation technologies innovations are another key component of the circular economy model. This study outlines microplastics' primary and secondary sources, summarizes the current methods for MPs elimination from different media along with their benefits and drawbacks, and highlights the importance of circular economy principles employment to minimize the MPs' pollution and their possible environmental repercussions
5th Metallurgical & Materials Engineering Congress of South- East Europe MME SEE Congress 2023, Book of Abstracts
No full textOn behalf of the Scientific and Organizing Committee, it is a great honor and pleasure to wish all the
participants a warm welcome to the Fifth Metallurgical & Materials Engineering Congress of South-East
Europe (MME SEE 2023) which is being held in Trebinje, Bosnia and Hercegovina, 07 - 10 June 2023.
The MME SEE 2023 is a biannual meeting of scientists, professionals, and specialists working in the fields of
metallurgical and materials engineering. The aim of the Congress is to present current research results related
to processing/structure/property relationships, advances in processing, characterization, and applications of
modern materials. Congress encompasses a wide range of related topics and presents the current views from
both academia and industry: Future of metals/materials industry in South-East European countries; Raw
materials; New industrial achievements, developments and trends in metals/materials; Ferrous and nonferrous
metals production; Metal forming, casting, refractories and powder metallurgy; New and advanced ceramics,
polymers, and composites; Characterization and structure of materials; Recycling and waste minimization;
Corrosion, coating, and protection of materials; Process control and modeling; Nanotechnology; Sustainable
development; Welding; Environmental protection; Education; Accreditation & certification.
The editors hope that Congress will stimulate new ideas and improve knowledge in the field of metallurgical
and materials engineering. The Congress has been organized by the Association of Metallurgical Engineers of
Serbia, with the co-organization of the Institute for Technology of Nuclear and Other Mineral Raw Materials,
Belgrade, Serbia, Faculty of Technology and Metallurgy, University of Belgrade, Serbia, Faculty of
Technology, University of Banja Luka, Bosnia and Herzegovina; the Faculty of Metallurgy, University of
Zagreb, Sisak, Croatia; the Faculty of Natural Sciences and Engineering, University of Ljubljana, Slovenia;
and the Faculty of Metallurgy and technology, University of Podgorica, Montenegro.
Financial support from the Ministry of Science, Technological Development and Innovation of the Republic
of Serbia to researchers from Serbia for attending the congress is gratefully acknowledged. The support of the
sponsors and their willingness to cooperate have been of great importance for the success of MME SEE 2023.
The Organizing Committee would like to extend their appreciation and gratitude to all sponsors and friends of
the conference for their donations and support.
We would like to thank all the authors who have contributed to this book of abstracts and also the members of
the scientific and organizing committees, reviewers, speakers, chairpersons, and all the conference participants
for their support of MME SEE 2023. Sincere thanks to all the people who have contributed to the successful
organization of MME SEE 2023
Microplastic textile fibers in urban soils of Serbia
No full textMicrofibers, as a considerable component of microplastic pollution in the environment have received
notable attention during past years. Fast fashion and extensive use of synthetic and semi-synthetic outfits,
aging, and discharge of used textile items are dominant sources of microfiber generation and ending up in
urban soils. Herein, we examined microfibers' presence in the urban soils of Sremska Mitrovica and Bor.
A flotation method based on density separation using saturated NaCl solution was utilized to assess
microplastics concentration in soils. The abundance of microfibers was 200 and 600 items per kg of soil,
respectively. Fiber structure was confirmed by ATR-FTIR analysis. Items isolated from soil from Sremska
Mitrovica contained the natural fiber of cotton, while microfibers detected in soil from Bor referred to
semi-synthetic polymer, viscose, i.e. rayon. Despite similar chemical structures based on cellulose,
differences in IR spectra allowed the distinguishing of these fiber types. This paper provides insight into
the current state of environmental pollution by microplastic fibers and suggests potential origin. More indepth
research on fiber content in soils, measures of prevention, and subsequent remediation should be
carried out to face the challenge of microfibers presence in the ecosystem, their entering the food chain,
and their impact on biota
Microbially inoculated chars strongly reduce the mobility of alachlor and pentachlorobenzene in an alluvial sediment
No full textThe objective of this study was to investigate the transport behavior of two organic and persistent contaminants (alachlor and pentachlorobenzene) on Danube alluvial sediment in the absence and in the presence of microbially inoculated biochar produced at 400 degrees C and three hydrochars produced at 180, 200, and 220 degrees C. Stainless steel columns were used for the sorption experiments in nonequilibrium conditions. Obtained results were modeled using the advective-dispersive equation under nonequilibrium conditions. Transport of these compounds through the alluvial sediment column showed that the retention time increased with increasing molecular hydrophobicity. Inoculated biochar increases the retardation of both compounds: twofold for pentachlorobenzene compared with alachlor as a consequence of a higher hydrophobicity. Obtained results indicate that the highest biodegradation coefficient was observed for pentachlorobenzene (lambda = 10) in alluvial sediment with addition of an inoculated hydrochar, which is assumed to be a consequence of biosorption. Moreover, all experiments on the columns indicate that the addition of inoculated chars yields a significantly higher R-d coefficient for pentachlorobenzene than for alachlor. Bacterial counts increased in all of the column experiments, which indicates the successful adaptation of microorganisms to experimental conditions and their potential for the removal of a large number of organic pollutants. Thus, addition of inoculated chars to contaminated sediments has the potential as a remediation technique to inhibit the leaching of pollutants to groundwaters. Integr Environ Assess Manag 2022;00:1-10
Nanoplastics in aquatic environments: Origin, separation and characterization: Review
No full textNaučnici su otkrili plastiku ranih 1900-ih, ali nisu shvatili kakve štetne efekte njena fragmentacija može imati na životnu sredinu 100 godina kasnije. Konkretno, čestice nanoplastike (NP) veličine od 1 do 100 nm mogu izazvati velike probleme u živom svetu zbog svoje velike specifične površine za adsorpciju drugih zagađujućih materija iz vode i njihove dalje bioakumulacije kroz lanac ishrane. Ne postoji poseban metod za identifikaciju, karakterizaciju i kvantifikaciju nanoplastike u vodenoj sredini. Iako mnoge metode razvijene za proučavanje mikroplastike nisu direktno primenljive na nanoplastiku, konvencionalne metode karakterizacije nanoplastike su obično zamorne jer proučavaju pojedinačne nanočestice u izolaciji. Pošto nanoplastika koja je rezultat razgradnje mikroplastike ima drugačija svojstva od sintetisanih plastičnih nanočestica, potrebno je razviti nove tehnike koje će nam pomoći da bolje razumemo ozbiljnost problema nanoplastike. Nanoplastika se može izolovati iz vodenog okruženja kombinacijom filtera i ultracentrifugiranja. U novijim publikacijama se navodi da će kombinovanje mikroskopije i spektroskopije, uz podršku hemometrijskih tehnika, omogućiti bolje razumevanje ponašanja čestica nanoplastike u životnoj sredini i organizmima. Velike nade se polažu u mikroskopiju u kombinaciji sa neuronskim mrežama za kvantifikaciju i karakterizaciju nanoplastike u složenim sistemima. Ovaj rad opisuje puteve degradacije plastike i formiranje nanoplastike u vodenim sredinama, kao i moguće metode za odvajanje i karakterizaciju nanoplastike u odnosu na nedavne publikacije.Scientists discovered plastic in the early 1900s, but didn't realize the detrimental effects its fragmentation could have on the environment 100 years later. In particular, nanoplastics (NPs) particles ranging in size from 1 to 100 nm can cause major problems in the living world due to their high specific surface area for the adsorption other polluting substances from water, and their further bioaccumulation through the food chain. There is no distinctive method to identify, characterize, and quantify nanoplastics in aquatic environments. Although many of the methods developed to study microplastics are not directly applicable to nanoplastics, conventional methods of characterizing nanoplastics are usually tedious because they study individual nanoparticles in isolation. Since nanoplastics resulting from the decomposition of microplastics have different properties than engineering plastic nanoparticles, new techniques need to be developed to help us better understand the seriousness of the nanoplastic problem. Nanoplastic can be isolated from the water environment by a combination of filters and ultracentrifugation. A recent publications states that combining microscopy and spectroscopy, supported by chemometric techniques, will alow a better understand he behavior of nanoplastic particles in the environment and organisms. High hopes are placed on microscopies combined with neural networks for the quantification and characterization of nanoplastics in complex systems. This article describes the degradation pathways of plastics and the formation of nanoplastics in aquatic environments, and possible methods for separation and characterization of nanoplastics in relation to recent publications
Bioaktivne kompozitne prevlake na bazi hidroksiapatita na titanu za primene u ortopediji / Bioactive hydroxyapatite-based composite coatings on titanium for orthopedic applications
No full textKompozitna prevlaka hidroksiapatita (HAP) sa prirodnim polimerima hitozanom (CS) i polivinil-alkoholom (PVA), kao i sa antibiotikom gentamicinom (Gent) je elektroforetski taložena na titanu, pri konstantnom naponu. Formiranje nove kompozitne HAP/PVA/CS/Gent prevlake je potvrđeno infracrvenom spektroskopijom sa Furijeovom transformacijom. Necitotoksični efekat istaložene HAP/PVA/CS/Gent prevlake je dokazan MTT testom prema dve ćelijske linije (MRC-5 i L929). Sposobnost HAP/PVA/CS/Gent prevlake da indukuje i promoviše osteointegraciju je pokazana ALP testom.Composite coating of hydroxyapatite (HAP) with natural polymers chitosan (CS) and poly(vinyl alcohol) (PVA) with the antibiotic gentamicin (Gent) was electrophoretically deposited on titanium from an aqueous suspension, at a constant voltage. Formation of a new composite HAP/PVA/CS/Gent coating was confirmed by Fourier transform infrared spectroscopy. Non-cytotoxicity of deposited HAP/PVA/CS/Gent coating was demonstrated by MTT assay towards two types of cell lines (MRC-5 and L929). HAP/PVA/CS/Gent coating ability to induce and promote the osseointegration process was proved by the ALP assay
Primena skenirajuće elektronske mikroskopije u istraživanju ležišta i pripremi mineralnih sirovina
No full textSkenirajuća elektronska mikroskopija (SEM) je nakon više od 50 godina komercijalne dostupnosti našla značajnu primenu u različitim granama nauke i tehnike, pa tako i u geologiji i rudarstvu. Razvoj elektronske optike i različitih elektronskih, rendgenskih i svetlosnih detektora, zasnovanih na brojnim efektima interakcije elektronskog snopa i analiziranog uzorka, omogućava detalјnu morfološku, strukturnu i hemijsku mikroanalizu, na milimetarskoj do nanometarskoj skali. Na taj način je moguće odrediti strukturu i teksturu ispitivanih materijala, kao i oblik, veličinu i hemijski sastav prisutnih faza; definisati mineralne vrste i način pojavlјivanja glavnih i primesnih elemenata; ispitati međusobno srastanje i stepen oslobođenosti pojedinačnih faza; ispitati habanje i lom materijala, i drugo. Sve veća dostupnost instrumenata, relativna jednostavnost analize i jasna vizualizacija dobijenih rezultata učinili su SEM metodu jednom od neizostavnih metoda karakterizacije, bilo da su u pitanju metalične i nemetalične mineralne sirovine, rudni koncentrati, flotacijska jalovina, veštački građevinski materijali, metali, legure ili drugi čvrsti materijali
Bioenergy Crop-Based Ecological Restoration of Degraded Land
No full textIncreasing land degradation worldwide asks for restoration solutions that are often multi-purposed by nature. Establishment of Bioenergy crops, such as perennial grasses and short-rotation woody crops offers possibilities for both successful eco-restoration of various marginal lands and energy production. Besides many recognized benefits in terms of increased soil carbon stocks, reduction of GHG gasses and economical gains, there are still many potential challenges in bioenergy crop cultivation and production, particularly in terms of negative environmental implications. Comprehensive scientific studies are trying to recognize and overcome their existence and scope. Creation of sustainable bioenergy crops-based ecosys-tems on the various types of degraded lands through affordable restoration approach could pose a challenging task, but by its realization the fractional intentions of several UN-SDGs can be achieved
Spectroscopy analysis of activated sodium carbonate
No full textMechanical activation of materials leads to qualitative changes in material structure. These changes can include the accumulation of energy in the form of weakening bonds in the crystal, disruption of the crystal lattice, agglomeration, and in some cases even the synthesis of a completely new substance. In this study, anhydrous sodium carbonate was mechanically activated for 28 minutes in a vibro mill at a frequency of 3000 oscillations per minute. After activation, the changes occurring in the activated material were monitored. The samples were placed in the atmosphere of air at room conditions for 31 days (relaxation period). It was observed that during the relaxation period moisture and carbon dioxide were absorbed by the activated sodium carbonate in form of hemisorption, forming sodium bicarbonate. The transformation mechanism was monitored by Fourier-transform infrared (FTIR) spectroscopy as a function of relaxation time. Characteristic groups were monitored: CO32-, HCO3- and OH-
Designing biocompatible high entropy alloys using Monte Carlo simulations
No full textThis study examines the potential of high-entropy alloys (HEAs) as promising biomaterials, with a specific
focus on the development of alloys with a low Young's modulus. Utilizing Monte Carlo simulations coupled
with machine learning techniques, the research identifies critical variables that significantly influence the
Young’s modulus, uncovering a notable correlation between specific heat and the elastic properties of the
alloys. The validation of the Extra Trees Regressor as a reliable predictive model in this study, furthermore,
facilitates the identification of promising HEAs with tailored properties. These findings provide significant
insights that are expected to guide future progresses in the development of HEAs as advanced biomaterials