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INTRODUCTION: The ubiquity of pathogenic yeast species in the human body and the increasing number of immunocompromised people acquiring infections have drawn attention to fungal infections [1]. Improved diagnostic imaging techniques and tools to study infection are necessary due to the commensal nature of pathogens yeast and the severity of the diseases they cause. The ability to label non-pathogenic yeast cells, such as the budding yeast Saccharomyces cerevisiae (S. cerevisiae), may facilitate the identification and monitoring of these microbes in different environments. The topic of interest in this research is the development of luminescent nano-biomaterials based on fluorapatite as a contrast agent for labeling and imaging S. cerevisiae. EXPERIMENTAL (or Materials and Methods): The method used to manufacture fluorapatite nanopowder has been previously reported in research [2]. After being acquired locally, S. cerevisiae was suspended in saline. One milligram of the FAP sample was added to the yeast suspension. After mixing the resultant suspension, it was left to incubate at room temperature for one hour without being stirred. Following treatment, cells were taken out, preserved, and prepared in triplicate for microscopy. MIPAR software has been used to analysethe obtained images. RESULTS AND DISCUSSION: Luminescent FAP nanoparticles were synthesized by precipitation and centrifugation at low temperature. The resulting single-phase nanomaterial exhibits cascade fluorescence in the violet and blue regions [2]. To investigate the performance of FAP nanoparticle fluorophores, cells of S. cerevisiae were labeled and observed with a Leica DMIL inverted fluorescence microscope. Nanofluoroapatite fluorophores were successfully labeled S. cerevisiae cells.MIPAR image analysis software extracted the luminescence of nano-biomaterials from yeast cells. CONCLUSIONS: In this study, S. cerevisiae was used as a yeast model which, after labelling with a fluorapatite-based cont

Acid mine drainage is a challenging environmental problem caused by mining activities. Long-term copper ore exploitation and vast amounts of mining waste lead to severe soil contamination as well as river and groundwater pollution. In this paper, research is focused on utilizing waste mine waters and off-balance parts of the mine deposit (such as flotation tailings) and converting their negative characteristics to an environmentally friendly one. In the authors’ previous work, acid mine water from Robule, which is part of the Bor copper mining and smelting complex in Serbia, was successfully treated using flotation tailings, and the resulting solution was suitable for safe discharge. This paper investigates the characteristics of the solid residue that remained after the treatment of the modified flotation tailings in order to evaluate the possibility of its safe disposal back into the environment. The solid residue was subjected to TCLP and EN 12457-4 tests as standard procedures that assess the leaching characteristics of a material. The solid residue was also exposed to long-term leaching with melted snow to simulate environmental conditions for one year. This drainage water was analyzed and compared with the results of the standard leaching procedures. The investigated treatments lead to improved economic and environmental effects, while the process itself is adjusted to preserve the environment.

Following the principles of sustainable development and circular economy, an innovative industrial symbiosis approach has been developed that uses already disposed voluminous waste. The research was focused on the utilization potential of vast amounts of flotation tailings, fly ash and acidic mine waters. Numerous previous case studies have pointed out the harmful, long-lasting environmental damage from waste disposal. In this case, the emphasis is on finding a practical approach for using industrial waste, specifically thermal power plant fly ash, in order to neutralize acidic mine waters resulting from tailings disposal. The proposed treatment gives waste a practical value, eliminates its harmful effect on the environment and redefines (lowers) regular waste management costs. In addition, it is possible to obtain valuable metals by exploiting and reprocessing acidic mine drainage.

The paper presents the results of the analysis of the influence of the synthesis parameters on obtaining the composite system (WAl12 + Al2O3)/Al with improved mechanical properties. The starting powders of Al and WO3 were homogenized until reaching the required composition with 1%, 2%, 5% and 7% WO3. After homogenization, the obtained samples were pressed under a pressure of 10 MPa. The sintering of the obtained samples was performed in an argon atmosphere at temperatures of 550 oC, 585 oC, 615 oC and 650 oC for 20, 40 and 60 minutes. As a result of the test, it was concluded that the sintering temperature, as well as the sintering time, do not have a significant effect on the increase in hardness of these composites. The main parameter that affects the increase in strength of these composites is the WO3 content. With an increase in the WO3 content, there is an increase in the hardness of the composite.

In oxygen converters, molten iron from the blast furnace is refined with steel waste under oxidizing conditions [1]. The injected oxygen passes into the iron melt, after which it reacts with the impurities. Analysis of exergy losses clearly indicates the place of energy losses in the observed process, so a detailed analysis can influence the improvement of a complex process [2]. Exergy losses occur due to technological imperfections such as heat dissipation or friction and system irreversibility according to the second law of thermodynamics [3]. The concept of exergy can be used for a better understanding of the feasibility of a process, as well as for the techno-economic analysis of the process at different variations of input/operating parameters. In this work througtful calculation of exergy oxygen convertor was done. According to the obtained data, out of a total of 972.2 MJ of thermal energy, which is released by exothermic reactions in the refining process, 817.5 MJ is pure exergy and can be used, the rest is anergy that arises due to irreversibility.

Aluminothermic welding has been used to connect railway rails for over a century. This technique has the advantages of flexibility, weld compactness, and simplicity. External energy is not required for the procedure. Exothermic heat is produced by chemical reactions of aluminothermic elements. To create a quality welded connection, the mold and pouring system must provide uniform pouring of hot steel without turbulence, even heat dissipation or cooling, and an acceptable micro and macro structure of steel free of internal and external faults. The design of the mould was constantly changing, necessitating costly industrial experimentation. As a result, the mould's design was constantly evolving, necessitating the use of costly experimental procedures in industrial settings. The latest iteration of the model the casting cavity was improved by adding hoes in the sand and putting rails on both sides in order to more aquratly simuate heat transfer. Software programs are emulating conventional casting procedures for thermite steel casting in welded railway connections to save money and effort on costly and timeconsuming industrial testing. For the 49E1 rail, NovaFlow & Solid CV were utilized to simulate casting thermite steel in the mould cavity or weld junction.

Railway rails have been linked using the aluminothermic welding process for over a century. This method has several advantages, including flexibility, compactness of the weld, and ease of execution. It is not necessary to employ outside energy to complete the procedure. It is provided by the exothermic effect of the chemical reactions of the aluminothermic combination's elements. The design of the mold with the pouring system, which should ensure even pouring of thermal steel without turbulence, then even heat dissipation or cooling in order to obtain an appropriate micro and macro structure of steel, free of internal and external defects, is an important factor in producing the required quality welded joint. As a result, the mold's design was constantly evolving, necessitating the use of costly experimental procedures in industrial settings. In this iteration of the model the casting cavity was improved by adding hoes in the sand and putting rails on both sides in order to more aquratly simuate heat transfer. Software programs are being used to simulate conventional casting procedures that can be used in the casting of thermite steel during the fabrication of welded railway connections in order to prevent costly and time-consuming industrial experimentation. The NovaFlow & Solid CV software package was used to simulate casting thermite steel in the mold cavity, i.e. in the weld joint, for the 49E1 rail.

Aluminothermic welding has been used to connect railway rails for over a century. This method has several advantages, including its versatility, the tightness of the weld it creates, and its ease of execution. To complete the procedure, no further power source is necessary. The design of the mold with the pouring system, which should ensure even pouring of thermal steel without turbulence, then even heat dissipation or cooling to obtain an appropriat micro and acro structure of steel free of internal and external defects, is one of several factors that contribute to a quality welded joint. As a result, costly experimental techniques in industrial settings were necessary to keep up with the ever-changing mould design. The model design was upgraded in comparison to the previous version [1], and will be imroved even further.The two sets of solid steel rails put on either side of the casting mould will be adjusted as heating media within the mould material category in the future, bringing the model closer to reality. As a result, cooling and heating temperatures will be more evenly distributed. Stress and strain modeling were performed to the preheated model to provide a more complete understanding of how shrinkage is related to stress. In future iterations of the model, we will either move the heat source to its right place approximately 40 cm above ground or adjust the temperature, diameter, and gas at the current site to more exactly reproduce real-life circumstances. Furthermore, during simulation setup, the replace material function may be used to model a new component that represents the divider that will be changed between air and silica sand material at the end of prehearing. Software programs are being used to simulate conventional casting procedures that may be used in the casting of thermite steel during the fabrication of welded railway connections in order to prevent costly and time-consuming industrial experimentation. The NovaFlow & Solid CV software suit

Phytomining although predominantly in its early stages on the broader scientific scope of investigation has garnered interest in metals such as Ni, Au, Zn or REE. Rare earth elements (REE) are commonly defined as the 15 lanthanides with the addition of Sc and Y. Since studies of other hyperaccumulating plant species have been conducted before, similar techniques were tried with REE. With the concentration threshold at 0.1 wt% of the dry biomass there have been identified about 22 plant species that hyperaccumulate REE from five families (Phytolaccaceae. Gleicheniaceae, Blechnaceae, Juglandaceae, Thelypteridaceae). One of the most studied REE hyperaccumulators is Dicranopteris linearis (formerly known as D.dichotoma), a fern native to China that grows on mine tailings. Generally, the techniques for REE phytomining can be separated into Pyrometallurgy, Hydrometallurgy, Biometallurgy and Novel approaches. Currently most of the research is still focusing on the optimal utilization of various hiperaccumulators and the enchantment of REE extraction from the soil as well as from the enriched biomass. Since recovery of REEs via phytomining is just in its infancy further multidisciplinary investigations are needed, especially when it comes to valorization and REE recovery. This paper presents a quick review for the concept of REE phytomining, current state of research, challenges and prospects.

Naučnici 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.

Acid mine drainage (AMD) is a waste from mining sites, usually acidic, with high concentrations of sulfates and heavy metal ions. This study investigates the AMD neutralization process using fly ash (FA) as an alternative material. Samples of FA from coal-fired power plants in Serbia (“Nikola Tesla” (EF) and “Kostolac” (KOST)) were analyzed and used. The results were compared with the treatment efficiency of commercial neutralization agent (NaOH). The alkaline nature of FA was the basis for use in the treatment process of the extremely acid Lake Robule (pH 2.46), located in the mining areas of eastern Serbia. The optimal S/L ratio for the AMD neutralization process determined for EF was 25 wt.%, and for KOST it was 20 wt.%. The mechanism of the neutralization process was analyzed using the ANC test and PHREEQC program. The element concentrations and pH values in solutions indicated that FA samples could neutralize Lake Robule with more than 99% of Al, Fe, Cu, Zn, and more than 89% of Pb precipitated. Formation of insoluble (oxy)hydroxide forms (Fe3+ and Al3+ ions) creates favorable conditions for co-precipitation of other trace metals (Cu, Zn, Ni, Pb, and Cd) from AMD, which is further enhanced by cation adsorption on FA particles. FA proved to be a more effective neutralization agent than NaOH due to its adsorption effect, while among the FA samples, KOST was more effective due to the aging process through the carbonization reaction. Using FA as an alternative material is a promising and sustainable method for treating AMD, with economic and environmental benefits.

The mining sector, nowadays, faces rising challenges to find suitable practice that are sustainable for already disposed waste streams (AMD, flotation tailings and fly ash) [1]. There is a growing tendency globally to use waste from various industries to neutralize AMD, which has both economic and environmental benefits. In attempt to connect mining waste with concept of sustainable development in the Republic of Serbia, several experiments were taken into consideration: neutralisation of AMD from Bor’s mine with a) flotation tailings from copper mine Majdanpek (FJM) b) fly ash (FA) from thermal power Nikola Tesla (EF) and Kostolac (KOST). All three samples of alternative product are voluminous, hazardous waste products, difficult and expensive for safe deposition, causes environmental pollution (by spontaneous leaching of useful components, which causes additional investment in the rehabilitation of that or reversibly lost compounds that pollutes the environment, or its dispersion by wind in surrounding streams and groundwater resources of drinking water, air or soil and also degradation by soil erosion) and can affects human health’s if are not regularly discharged. But its benefits are that there are free of charge alkaline wastes, suitable to neutralize the AMD by altering pH, which leads to precipitation of valuable metal which can be reused, such as Fe or Cu. The chemical and mineralogical composition of the initial samples of FJM and FA was evaluated two standard leaching tests: TCLP and EN 12457-4, as well as Acid Neutralization Capacity test. These base materials were shown to have a large capacity to neutralize acid, making them a highly effective alternative material for neutralizing acid mine drainage and eliminating metals, even better than results of neutralisation with NaOH, as conventional reagent. According to the findings the FJM and FA neutralization experiments precipitated more than 99 % of Al, Fe, and Cu, 90 % of Pb, and 92 % of Zn. Leaching of

Recent mankind demand for electronic devices is in constant upgrowth, those devices always contain printed circuit boards (PCB) which are mainly constructed of plastics, semiconductors and decent content of various metals. Hence, in the end-of-life of those products, it is highly recommended to recover those materials or functionalize those waste into other products or feed materials, in order to lessen their harmful impact on the environment. One of the promising processing procedures is hydrometallurgical treatment, since it is cost-effective and simple. In order to recover metals as aqueous soluble salts, crushed and milled PCB is air-pyrolyzed and obtained powder is processed as start material in leaching experiments. The use of concentrated aqua regia led to the passivation of solid material and consequently impede the leaching process. Dry-digestion leaching using concentrated sulfuric acid partially leached some metals. The highest leaching rate (≥70 %) has been achieved using diluted sulfuric acid (for Al, Ni, Fe, Co, and rare-earth) and copper yield was highest utilizing 2 M H2SO4 + 3 M H2O2; S/L = 0.1 g/ml. While sulfuric acid has accomplished some results for enumerated leachates, it achieved limited success for leaching Ba, Pb, Ag, Au, Pt and Pd. Overall findings imply that hydrometallurgical procedures may be used but only together with previous separation techniques. That approach would increase overall leaching with oxidizing agents and enable leaching of noble metals.

Razvoj industrije uticaće na potražnju i cenu nikla u narednim godinama, što otvara mogućnost za razvoj i primenu dodatnih načina njegove eksploatacije iz sekundarnih resursa. Fitorudarenje nikla je in situ tehnologija koja koristi biljke sa mogućnošću hiperakumulacije ovog elementa za njegovo uklanjanje iz subekonomskih ruda. Ova studija predstavlja analizu trenutno ustanovljenih metoda i postignutih rezultata u hidrometalurškim postupcima pri fitorudarenju nikla, kao i mogućnost da se na terotoriji Srbije razviju adekvatne metode i primeni ova tehnologija u praksi. Naša istraživanja su dokazala da je moguće sintetisati soli nikla iz hiperakumulatorske vrste Odontarrhena muralis, koja se od prirode javlja na ultramafitskim zemljištima u Srbiji. U preliminarnim istraživanjima na domaćoj populaciji vrste koristeći ustanovljene metode, usled objektivnih operativnih ograničenja i manje količine početne biomase dobijene su soli nikla čistoće 60% i 73%. Obimnija istraživanja, koja podrazumevaju veće količine početne biomase i namensku kultivaciju biljaka na odgovarajućim ultramafitskim zemljištima, neophodna su kako bi se mogle ispitati dodatne mogućnosti za proizvodnju nikla i široke lepeze niklovih produkata, kao i tehnološke aspekte ove proizvodnje sa posebnim naglaskom na održivost i zaštitu životne sredine. Imajući u vidu takve benefite, kao i činjenicu da je cena nikla u trendu porasta, fitorudarenje u budućnosti može imati značajniji udeo u proizvodnji metala nikla i njegovih soli.

Numerous electronic devices are put out of use every day, and most of them have printed circuit boards (PCBs) that are lased and imbued with various precious and valuable metals in abundant amounts. This makes PCB an unexploited resource of the future from whom many metals such as Cu, Zn, Sn, Al, Li, Co, Nd, Pd, Pt, and Ba can be extracted. Since leaching plastic polymers can lead to the vaporization of toxic fumes, to avoid this the PCB are pyrolyzed. The PCB is crushed and the pyrolyzed product is a powder that can easily be separated into metallic and nonmetalic fractions. The aim of this work is to investigate the influence of ultrasound sonification on the nitric acid leaching of pyrolyzed printed circuit board (PPCB) powder. The impact of ultrasound sonification had a positive effect on the leaching degree for all investigated metals except for Cobalt. The biggest difference in leaching degree was for Lithium while the smallest was for platinum. Because of the complexity of the PPCB powder system overall, the measurement of oxidation-reduction potential (ORP) didn’t yield any insight into the leaching mechanism since the measured values mainly followed the expected trend due to nitric acid degradation.

For more than a century, railway rails have been joined using the aluminothermic welding process. The flexibility, compactness of the weld, and ease of execution are all advantages of this process. It is not necessary to use external energy to finish the operation. It is provided by the exothermic effect of the chemical reactions of the elements of the aluminothermic combination. The design of the mold with the pouring system, which should ensure even pouring of thermal steel, without turbulence, then even heat dissipation or cooling in order to obtain an appropriate micro and macro structure of steel, free of internal and external defects, is an important factor in producing a welded joint of the required quality. As a result, the design of the mold was continually developing, necessitating the adoption of expensive experimental approaches in industrial settings. To eliminate costly and time-consuming industrial experiments, software applications are being employed to imitate aditional casting methods that can be used in the casting of thermite steel during the fabrication of welded railway connections. This study presents a simulation of casting thermite steel in the mold cavity, i.e., in the weld joint, for the 49E1 rail using the NovaFlow & Solid CV software package.

Zagađenje vodenih resursa mikro- i nano-plastikom je prepoznato kao globalni problem. Trenutno ne postoje dostupne specifične metode za identifikaciju, karakterizaciju i kvantifikaciju nanoplastike u vodenim sredinama. Mnoge od metodologija razvijenih za analizu mikroplastike ne mogu se direktno primeniti na nanoplastiku, dok konvencionalne metode karakterizacije nanoplastike obično izoluju i proučavaju pojedinačne nanočestice, što može biti naporan i dugotrajan proces. Korišćenjem mikroskopskih tehnika u kombinaciji sa spektroskopijom, moguće je ubrzati proces analize, ispitati morfologiju i veličinu čestica i istovremeno identifikovati hemiju. Pošto nanoplastika nastala degradacijom mikroplastike ima drugačija svojstva od sintetisanih nanočestica plastike, neophodno je kreirati nove analitičke i mikroskopske tehnike koje će pomoći da se bolje razume ozbiljnost problema nanoplastike. Ovaj rad ima za cilj da identifikuje metode koje bi mogle da se primene za odvajanje i karakterizaciju nanoplastike iz vodenih sredina., Pollution of water resources with micro- and nanoplastics is recognized as a global problem. Currently, there are no specific methods available for the identification, characterization and quantification of nanoplastics in aquatic environments. Many of the methodologies developed for the analysis of microplastics cannot be directly applied to nanoplastics, while conventional nanoplastic characterization methods usually isolate and study individual nanoparticles, which can be a laborious and time-consuming process. By using microscopic techniques combined with spectroscopy, it is possible to speed up the analysis process, examine the morphology and size of the particle and identify the chemistry at the same time. Since nanoplastics created by the degradation of microplastics have different properties than synthesized plastic nanoparticles, it is necessary to create new analytical and microscopic techniques that will help to better understand the seriousness of the nanoplastics problem. This work aims to identify methods that could be applied for the separation and characterization of nanoplastics from aquatic environments.

Electric waste from numerous devices that are put out of use every day has some form of printed circuit board that contains precious and valuable metals in their components. In order to extract these metals, the printed circuit boards were crushed and pyrolyzed into powder. The fine pyrolyzed printed circuit board (PPCB) powder was separated into fractions, and the fine metallic fraction was used as a raw material for metal leaching extraction. In order to better understand how various metal species react in leaching media, several leaching agents were used (sulfuric acid, nitric acid, glycine, and acid mine drainage-AMD) alone, and with the addition of hydrogen peroxide. Additionally, the influence of the S/L ratio and leaching temperature were investigated in sulfuric acid leaching solutions, as this is the one most widely used. In one case, the reactor was heated in a thermal bath, while in the other, it was heated in an ultrasonic bath. Lastly, several experiments were conducted with a (consecutive) two-pronged leaching approach, with and without applied pretreatment. The aim of this paper is to give a multifocal and detailed approach to how metals such as Al, Cu, Co, Zn, Sn, and Ca behave when extracted from fine PPCB powder. However, some attention is given to Nd, Pd, Pb, and Ba as well. One of the main findings is that regardless of the pretreatment or the sequence of leaching media applied, consecutive two-pronged leaching cannot be used for selective metal extraction. However, AMD was found to be suitable for selective leaching with very limited applications.

The aim of this work was to establish a temperature of finish rolling stage of Nb/Ti microalloyed steel containing 0.06 wt.% C, 0.77 wt.% Mn, 0.039 wt.% Nb and 0.015 wt.% Ti, using physical simulation. Samples were subjected to laboratory simulation at a twist plastometer at high temperatures, i.e. between 825 and 950 degrees C. Five pass deformation and interpass times were selected in accordance with a processing parameters at five stand finishing hot strip mill. Restoration (recovery and/or recrystallization) behavior was evaluated by calculation of Fraction Softening (FS) and Area Softening Parameter (ASP) values. At 950 degrees C all individual pass stress-strain curves, FS and ASP show full recrystallization in all interpass intervals. On the other hand, with a decrease in temperature to the interval of 875-825 degrees C, the extent of restoration is decreasing, leading to recovery as a sole softening mechanism at 825 degrees C, which was confirmed by the stress-strain curve shape, and values of FS and ASP. It is assumed that, due to high supersaturation, strain-induced precipitation promoted pinning of grain and subgrain boundaries and suppressed recrystallization. Therefore, the critical temperature for finish rolling was estimated to be 825 degrees C.

Iako u ranoj fazi istraživanja fitorudarenje je podstaklo interesovanje u ispitivanju metala poput Ni, Au i retkih zemalja (REE). Međutim zagađenje cinkom iz rudničkog otpada, topionica, letećeg pepela i drugih antropogenih izvora postalo je ekološki problem. Fitoremedijacija hiperakumulirajućim biljkama pokazala se kao jedno od rešenja za smanjenje tog zagađenja. Stoga se pojavila i potreba za korišćenjem ili odlaganjem biljaka-hiperakumulatora cinka. Pošto su ranije sprovedena ispitivanja određenih hiperakumulatora za ekstrakciju metala, slični hidrometalurški i pirometalurški postupci ispitani su i za Zn. Hidrometalurški pravac ispitivanja fokusiran je na proizvodnju grubih eko katalizatora za potrebe organske hemije ili separaciju metalnih hidroksida cementacijom. Ovo je postignuto kiselim luženjem pepela dobijenog sagorevanjem nadzemne biomase. S druge strane, pirometalurški pravac više je fokusiran na bezbedno i ekološki prihvatljivo odlaganje proizvoda sagorevanja poput pepela i biočađi, uz postizanje nulte emisije toksičnih gasova pri pirolizi biomase. Bez obzira na pristup, potrebna su dalja istraživanja kako bi se ispitala stabilizacija metala koji zaostaju u čvrstoj frakciji tokom sagorevanja kao i smanjenje sadržaja metala u emitovanim gasovima. Do sada nijedna od ovih tehnologija nije dovedena do poluindustrijskih razmera u ispitivanjima, mada postoji potencijal u povezivanju ova dva pristupa., Phytomining, although predominantly in its early stages on the broader scientific scope of investigation, has garnered interest in metals such as Ni, Au, or rare earth elements (REE). However, Zn pollution from mine wastes, smelters, coal ash and other anthropogenic sources has become an environmental problem. Phytoremediation by hyperaccumulating plants is one of the proposed solutions to mitigate the pollution. Therefore, a need to utilize or dispose Zn hyperaccumulating plants occurred. Since studies of certain hyperaccumulating plant species have been previously conducted in order to extract metal products, similar hydrometallurgical and pyrometallurgical techniques were tried with Zn. The hydrometallurgical route was more focused on producing crude eco catalysts for organic chemistry or separating metal hydroxides by cementation. This was achieved with acid leaching of the ash which was obtained by calcinating the aboveground plant biomass. On the other hand, the pyrometallurgical route was more focused on safe and eco-friendly disposal of combustion products such as ash or biochar, while achieving zero toxic gaseous emissions from biomass pyrolysis. Regardless of the approach further research is needed to investigate the stabilization of metals that remain in the solid fraction during combustion and lowering the metal content in produced gases. So far, none of these technologies have been brought to a semi industrial scale and there is the potential of linking those two approaches together.

Fitorudarenje je aktuelna biotehnologija u razvoju kojom se ekstrahuju retki i dragoceni metali iz prirodno obogaćenih ili zagađenih zemljišta uz pomoć biljaka hiperakumulatora. Na teritoriji Balkana hiperakumulatorske vrste usvajaju prevashodno nikl, cink, talijum, bakar i arsen. U ovom radu dat je pregled do sada ispitanih tehnologija za ekstrakciju ovih elemenata iz biomase hiperakumulatorskih vrsta širom sveta, kao i područja potencijalne primene dobijenih produkata. Na teritoriji Srbije fitorudarenje ima perspektivu, i potrebno je vršiti ispitivanja u pravcu pronalaženja upotrebne vrednosti dostupnih hiperakumulatora, kao i razvoja tehnologija za ekstrakciju metala iz njihove biomase., Phytomining is a currently developing biotechnology aiming to extract rare and precious metals from naturally enriched or polluted soils with the help of hyperaccumulator plants. On the territory of the Balkans, hyperaccumulating species mainly accumulate elements such as nickel, zinc, thallium, copper and arsenic. This paper provides an overview of the studied technologies around the world for the extraction of these elements from hyperaccumulator's biomass, as well as the areas of potential application of the obtained products. Phytomining has a potential for development in Serbia, and for this purpose it is necessary to utilitized available hyperaccumulators, as well as to investigate technologies for the extraction of metals from their biomass.

Cleavage fracture of the V and Ti-V microalloyed forging steels was investigated by the four-point bending testing of the notched specimens of Griffith-Owen's type at -196 degrees C, in conjunction with the finite element analysis and the fractographic examination by scanning electron microscopy. To assess the mixed microstructure consisting mostly of the acicular ferrite, alongside proeutectoid ferrite grains and pearlite, the samples were held at 1250 degrees C for 30 min and subsequently cooled instill air. Cleavage fracture was initiated in the matrix under the high plastic strains near the notch root of the four-point bending specimens without the participation of the second phase particles in the process. Estimated values of the effective surface energy for the V and the Ti-V microalloyed steel of 37 Jm(-2) and 74 Jm(-2), respectively, and the related increase of local critical fracture stress were attributed to the increased content of the acicular ferrite. It was concluded that the observed increase of the local stress for cleavage crack propagation through the matrix was due to the increased number of the high angle boundaries, but also that the acicular ferrite affects the cleavage fracture mechanism by its characteristic stress-strain response with relatively low yield strength and considerable ductility at -196 degrees C.

Phytomining is a technique that aims to obtain metal(oid)s or their products using hyperaccumulating plant species that grow on substrates rich in heavy metals, but not enough to justify conventional mining. After harvesting, the biomass is combusted and the ash is used as bio-ore for the production of pure metal(oid)s or their salts. Most hyperaccumulating plants accumulate Ni, which occurs naturally in high concentrations in ultramafic soils. A large number of Ni hyperaccumulators are found in the genus Odontarrhena, which is most commonly used in phytomining studies. In order to obtain the largest amounts of Ni and the salts of the higher purity, it is necessary to choose the most suitable ash processing treatment. This study shows results of obtaining Ni salts from the ash of Odontarrhena muralis by hydrometallurgical process in the form of ammonium nickel sulfate hexahydrate, Ni(NH4)2(SO4)2x6H2O - (ANSH). Odontarrhena muralis from ultramafic sites at West Serbia accumulates Ni at concentrations of 3300 mg kg-1 and is a good candidate for the phytomining process. By biomass combustion, during which biomass weight decreases for 92.7%, ash was obtained as a suitable raw material for Ni extraction. Out of gained mass of crude ash, 11,71% was yielded as ANSH crystals.The obtained purity of ANSH was 73%, which is slightly lower compared to similar studies, but good enough to show the potential for phytomining application. By optimizing the purification process that precedes precipitation of the ANSH crystals, the purity of recovered crystals can be additionally increased, influencing the economic feasibility of the process. Moreover, by selecting appropriate agronomic measures, it is possible to obtain biomass of O. muralis with increased concentration of Ni in aboveground parts, which would increase the initial concentration of Ni in bio-ore that is entering the extraction process.

The minerals with unique properties such as mica minerals have promising approach in environmental and industrial sphere. In this study, cobalt ferrite/expanded vermiculite (CoFe2O4/EV) composite was prepared by in-situ method. Both composite and base materials are characterized by FTIR, XRD and SEM techniques, while the CEC and point of zero charge (pHPZC) was also determined. The adsorption properties of CoFe2O4/EV and EV have been investigated in a batch system, for the Ni (II) sorption from water. Adsorption experimental results were fitted by kinetic and adsorption models, and resulted in ionic exchange mechanism with maximum adsorption capacity of 23.2mg g-1 (298 K).

Coal is a well-known fossil fuel. It was used as a non-renewable energy source for several centuries. Nowadays it is mainly used for electricity generation in power plants or heat generation for industrial and home utilization. There are many types of coal that differ in composition and calorific value, as well as in the amounts of undesired hazard substances produced by combustion. Depending on the coal composition, environmental impact can be reduced by its treatment before combustion. One of the cheap and effective methods is the chemical leaching of coal that reduces sulfur content and the amount of mineral matter (ash). Lowering the ash amount increases the calorific value of coal, reduces its transportation cost, and reduces the negative environmental impact of toxic elements, which are usually present in ash. Another benefit of coal leaching, that results from lowering the sulfur content is reduced emission of toxic gases (SO2 and SO3) during combustion. In order to determine the optimal leaching conditions for the treatment of different types of coal, numerous studies have been done, investigating various chemical reagents, including inorganic and organic acids, alkalis, oxidative reagents, and their combinations [1, 2]. The key parameters that effect leaching efficiency are type and concentration of reagent, reaction temperature, the mass ratio between coal and leaching reagent, coal particle size, and reaction time. The degree of leaching efficiency is measured by the level of demineralization and desulphurization [3]. The current review summarises recent results and further plans for the development of an efficient and environmentally friendly method for the chemical leaching of Serbian sub-bituminous coal.

All over the world, huge amounts of coal are available and it is utilized in large quantities for different purposes. The coal combustion causes environmental problems, such as the release of toxic metals and other pollutants into wastewaters, emission of noxious gases, produce of ash dumps, etc. One of the solutions for the reduction of environment pollution, caused by coal combustion, is demineralization and desulphurization of coal. In that sense, treatment of coal by different chemical reagents becomes important. A subbituminous coal, used in this study was taken from the Bogovina - East field (Lower Miocene » 20-16 Ma) of the Bogovina Basin, which is located in Eastern Serbia. The sample was selected based on the previous studies of Bogovina - East field which indicated a high amount of sulphur, relatively high percent of mineral matter and considerably amount of liptinites for humic coal, which represent the most reactive maceral group. The aim of the study was an attempt to reduce the amount of ash and sulphur in coal, keeping the organic matter unaltered as possible, using simple and cheap method e.g. treatment with hydrochloric acid (HCl). Ash and total sulphur content was determined before and after HCl leaching. In addition characteristics of initial and treated coal were tracked by X-ray diffraction (XRD) analysis and Fourier-transform infrared (FTIR) spectroscopy. The obtained results showed that the high percentage of deashing (» 80 %) was achieved with cheap hydrochloric acid. XRD analysis of ash before and after sample treatment provides more information about mineral phases in coal and effects of chemical leaching. FTIR analysis indicates almost no changes in structure of coal organic matter after treatment by HCl, which is important for further coal usage (e.g. combustion). On the other hand, the applied chemical leaching with HCl had low impact on the sulphur content in Bogovina coal (desulphurization percentage » 8 %). Therefore, in future resear

Acer negundo L. is recognized as an invasive deciduous tree species that tends to grow and spread out of its natural range posing a threat to the biodiversity of the impacted areas. Although invasive plant species are considered to negatively affect ecosystems, their biomass can be used for environmental benefits. In order to find abundant and inexpensive sorbent for wastewater purification and metal pollution minimization, A. negundo leaf biomass was selected and investigated for that purpose. Since lead is well known as a common pollutant occurring in various industrial effluents with harmful effects on biota, it was selected for the sorption experiments. Acer negundo L. (AN) samples were collected at the unpolluted area in Mountain Avala, Serbia. After milling and sieving, the prepared sorbent was used in batch system sorption experiments. Experiments were conducted under isothermal conditions, by adding a precise amount of sorbent in the lead solution of known initial concentration. The adsorption performance of the obtained biomass-derived material (AN) was evaluated by testing several operational parameters: initial pH value, initial sorbent dosage, contact time, and initial lead concentration. The experimental parameters were optimized in order to determine the most appropriate conditions for Pb(II) removal. Maximum lead uptake occurs at pH 5, with 2g/L of sorbent dosage. The kinetic study revealed very fast adsorption, with equilibrium occurring after an initial 15 min of contact between sorbent (A. negundo leaf biomass) and sorbate (1mmol/L of lead solution). After this contact time, the residual metal concentration started to increase indicating the desorption process. Data obtained from sorption experiments were subjected to equilibrium modeling: they were fitted by two-parameter models (Langmuir and Freundlich). Results showed that the maximal adsorption capacity of a sorbent is 109 mg/g. Obtained results suggest that Acer negundo leaf biomass can be suc

Due to the tendency of spreading out of its natural habitat and posing a menace to the surrounding species and biodiversity of the area under its influence, Acer negundo L. is known as the deciduous invasive tree species. Even though it is considered harmful for ecosystems, the biomass of this invasive species can be utilized for the purpose of wastewater remediation. A. negundo leaf biomass (AN) was investigated for its adsorption potential to bind the lead ions from an aqueous solution. The lead was selected for the sorption experiments, as it is a well-known pollutant often found in various industrial effluents. Acer negundo L. leaves were collected from the protected area of the outstanding natural landscape “Veliko ratno Ostrvo” in Belgrade. Experiments were carried out in a batch system under specific operational conditions. Precise amounts of sorbent were added in the Pb (II) solutions of known initial concentrations, and the optimal operational parameters were further evaluated. Parameters such as lead concentration, pH value, contact time, and sorbent dosage were tested and optimized for increasing the adsorption performance of the obtained sorbent. Maximum Pb (II) uptake occurred at pH 3,5 and sorbent dosage of 2 g/L. Very fast adsorption was noticed by the kinetic study, with equilibrium state achieved after the initial 2 min of sorbent (A. negundo)-sorbate (1 mol/L Pb (II) solution) contact. Obtained data were subjected to equilibrium modeling by using Langmuir and Freundlich equations. Maximum adsorption capacity reached 101,5 mg/g. According to these results, sorbent prepared from Acer negundo leaf powder has an outstanding potential to be applied for lead removal from contaminated waters.

Phytomining is a new promising technique that is based on using hyperaccumulating plants which biomass is utilized as a bio-ore for metal extraction. The Ni-hyperaccumulating species Odontarrhena muralis is widely distributed on ultramafic soils in Serbia, and could be a promising candidate for Ni agromining. In the present study, efficiency of a hydrometallurgical process for Ni recovery using biomass of O. muralis wild population through the synthesis of Ni salts from plant ash in the form of ammonium nickel sulfate hexahydrate, Ni(NH4)(2)(SO4)(2) 6H(2)O-(ANSH) was assessed. The average Ni content in the plant from ultramafic sites in West Serbia was up to 3.300 g kg(-1). The mass yield of ANSH crystals from the crude ash was similar to 12 % with the average purity of 73 % were obtained. By optimizing the purification process before precipitation of ANSH crystals, it is possible to obtain salt crystals of higher purity, which increases the economic profitability of this process. The results of this preliminary study on wild population of O. muralis show the increased potential for implementation of phytomining practices as an alternative way of Ni extraction on ultramafic sites in Serbia.

Sodium carbonate is a material that is very good sorbent of carbon dioxide from the atmosphere, and it is a reason of it is increasing importance in environmental protection. In order to improve it is sorption characteristics, activation of Na2CO3 was performed by mechanochemical procedure and monitoring of changes during the relaxation time. This research is based on differential thermal analysis with thermogravimetry, in order to determine the changes that occurred on the activated samples during the relaxation period under controlled conditions. Sodium carbonate was activated for 2 and 7 minutes in a vibro mill, and then the activated samples were deposited in at room temperature and atmosphere of carbon dioxide at a humidity of 95% for 96h.

Isothermal transformation characteristics of a medium carbon Ti-V microalloyed steel were investigated using light microscopy, scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and by uniaxial compressive testing. Samples austenitized on 1100 degrees C were isothermally treated in the range from 350 to 600 degrees C and subsequently water quenched. The final microstructure of the samples held at 350 degrees C consisted of bainitic sheaves and had compressive yield strength, approximately from 1000 MPa, which is attributed to high dislocation density of low bainite. At 400 and 450 degrees C, acicular ferrite became prevalent in the microstructure. It was also formed by a displacive mechanism, but the dislocation density was lower, leading to a decrease of compressive yield strength to approximately 700 MPa. The microstructure after the heat treatment at 500 degrees C consisted of coarse non-polygonal ferrite grains separated by pearlite colonies, principally dislocation free grains, so that the compressive YS reached a minimum value of about 700 MPa. The microstructure of the samples heat-treated at 550 and 600 degrees C consisted of pearlite and both grain boundary and intragranular ferrite, alongside with some martensite. After 600 s, austenite became stable and transformed to martensite after water quenching. Therefore, the presence of martensite increased the compressive YS to approx. 800 MPa.

U radu su prikazani i diskutovani rezultati luženja polimetalnog sulfidnog Cu-Zn-Pb koncentrata rastvorom natrijum-nitrata i sumporne kiseline pri atmosferskom pritisku. Prikazan je hemijski i mineraloški sastav polaznog koncentrata i čvrstih ostataka nakon procesa luženja. Hemijske reakcije luženja i mogućnosti njihovog odvijanja analizirane su primenom termodinamičke analize na osnovu izračunatih Gibbsovih energija i analize E-pH dijagrama. Eksperimentalno je analiziran uticaj temperature i vremena na stepen izluženja korisnih metala iz sulfidnog koncentrata. Pokazano je da je moguće dobiti bakar, cink i železo u rastvoru u obliku sulfata, dok olovo u obliku anglesita (PbSO4) ostaje u čvrstom ostatku nakon procesa luženja. Železo se oksidiše u Fe (III) -sulfat, koji učestvuje u luženju sulfidnih minerala i prelazi u Fe (II) -sulfat., The results of polymetallic sulphide Cu-Zn-Pb concentrate leaching with sulphuric acid in the presence of sodium nitrate as an oxidizing agent, at atmospheric pressure, are presented and discussed. Chemical composition and phase ratio of the starting concentrate and solid residuals after the leaching process are shown. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the calculated Gibbs energies and analysis of E-pH diagrams. The influence of temperature and time on the leaching degree of the concentrate's components is experimentally determined. It is shown that it is possible to obtain copper, zinc and iron in a solute form, while lead in the anglesite (PbSO4) form remains in the solid residual after the leaching process. The iron is being oxidized to Fe(III)-sulphate, which takes part in a sulphide leached minerals and turns into Fe(II)-sulphate.