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Towards Circularity in Serbian Mining: Unlocking the Potential of Flotation Tailings and Fly Ash
No full textThis paper examines sustainable industrial practices in Serbia, particularly in
the mining and energy sector, focusing on the potential of flotation tailings and fly ash, as
materials with the largest share in disposed waste in Serbia in 2023 (95%). It highlights
the environmental challenges of mining waste and explores innovative approaches to
waste management within the circular economy framework. The study analyzes the
current state of mining waste in Serbia, particularly in copper mining regions in the east
of the country. It discusses the potential for metal recovery from waste and its reuse in
various industries. The research also investigates the use of fly ash from thermal power
plants as a valuable resource in the construction industry and other sectors. The paper
reviews existing initiatives and legislation in Serbia in order to promote sustainable mining
practices and waste utilization. By presenting case studies and potential applications, the
study demonstrates how implementing circular economy principles in the mining sector
can contribute to environmental protection, resource conservation, and economic growth
in Serbia. The comprehensive overview of the current state in Serbia provides a solid
foundation for establishing a higher degree of circularity in the mining and energy sectors
Theoretical fundamentals of chemical reactions in the solid phase
No full textChemical reactions in the solid phase are characterized by many specificities. The study of such reactions, with regard to the condensed state, eliminates the need to introduce many approximations that are common when considering reactions in the liquid phase or heterogeneous reactions, other laws, specific and inherent only to the solid state of matter. These make the scientific field of solid-state chemistry far more complex, due to the very strong need for a comprehensive multidisciplinary approach. The basic theoretical principles from the fields of physics, chemistry, physical chemistry and chemical technology are equally important. The article gives an example of mechanochemical synthesis of the neutralization type, and barium oxide as the base component and titanium oxide as the sisal component of the mixture are activated. In order to determine the changes that occur due to the mechanical activation of the starting materials, barium oxide and titanium oxide were ground in a stoichiometric ratio for 440 minutes. The analysis determined that a mechanochemical synthesis had taken place and that barium titanate with a degree of synthesis of 0.99 had been obtained. This was confirmed using X-ray structural analysis, which monitored the state of the activated material as a function of the time of activation
Significance of 3’-methyl-1,2-cyclopentenophenanthrene in characterization of crude oils (SE Pannonian Basin, Serbia)
No full textC20, C21 and C26-C28 triaromatic steroids are widely used in investigations of sedimentary organic matter (OM). On the other hand, C18 triaromatic steroid, 3’-methyl-1,2-cyclopentenophenanthrene, also known as Diels’ hydrocarbon, has attracted much less attention. During the investigation of crude oils from the most important oil fields in Serbia (in the southeastern part of the Pannonian Basin), considerable concentrations of 3’-methyl-1,2-cyclopentenophenanthrene (abbreviated here as MCpP) were observed in the total ion chromatograms of aromatic fractions. Therefore, the objective of this study is to establish the applicability of MCpP in characterization of crude oils.
Rowland et al. (1986) detected MCpP in the hydrous pyrolysis products of dolomitic siltstone and organic-rich oil shale, and suggested that this compound is the main product of thermal degradation of C26-C28 (S+R) triaromatic steroids, whereas C21 and C22 homologues were obtained with very low abundances. Therefore, in the current study, a MCpP index: MCpPI = 10 × MCpP/(MCpP+ΣC26-C28 (S+R) triaromatic steroids) was introduced and its applicability was estimated on the set of 57 crude oils (from non-biodegraded, up to the 4th stage of biodegradation), which maturity ranges from early mature to very mature, corresponding to a vitrinite reflectance (Rr) of 0.60-1.05%.
To test a possible impact of the sources and depositional environment of precursor OM on the MCpPI, it was correlated with the following ratios: Σsteranes/Σhopanes, oleanane index, gammacerane index, C27αα(R)/C29αα(R) sterane, C28αα(R)/C29αα (R) sterane, (C19+C20)/C23 tricyclic terpane, C25/C26 tricyclic terpane, C35αβ(S)/C34αβ(S) hopane, pristane/phytane, dibenzothiophene/phenanthrene and the MTTC parameter derived from distributions of alkylated 2-methyl-2-(4,8,12-trimethyltridecyl)chromans. No correlation was observed with any of the mentioned parameters.
MCpPI showed an excellent positive correlation with the related maturity parameters based on triaromatic steroids, C20/(C20+C28 R) and (C20+C21)/ΣC26-C28 (S+R), with correlation coefficients (r) of 0.96 and 0.99, respectively (linear dependence). The proposed parameter also has a significant positive correlation with frequently used sterane maturity ratios, C29αα(S)/(C29αα(S)+αα(R)) and C29ββ(R)/(C29ββ(R)+αα(R)) (r = 0.91 and 0.93, respectively). However, the best fit curve in this case was logarithmic, which is reasonable since the mentioned sterane ratios attain their empirical equilibrium values at the peak of the main stage of oil window and at the beginning of the late stage of oil window. MCpPI was further correlated with the Ts/(Ts+Tm) and C27 βα(S) diasterane/(C27 βα(S) diasterane + C27 αα (R) sterane) ratios; a significant positive correlation for the linear regression was detected (r = 0.89 and 0.91, respectively).
MCpPI was also correlated with the parameter MDBTR derived from the distribution of methyldibenzothiophenes. The linear regression was observed with the correlation coefficient of r = 0.98. The correlation of MCpPI with phenanthrene maturity ratios MPI 1 and MPDF was also statistically significant at a level of 99.9%, but the correlation coefficients (r = 0.74 and 0.73) were apparently lower than for the other tested parameters. This result may be attributed to a possible thermal cracking of the D-ring of MCpP, which yields alkylphenanthrenes, including 2- and 3-methylphenanthrene (MP) as expected products. Indeed, an excellent correlation was observed between 2-MP/MCpP and 3-MP/MCpP, with a correlation coefficient of r = 0.99. Furthermore, 2-MP/MCpP exhibited a significant positive correlation with MCpPI (r = 0.84) and MDBTR (r = 0.90), with the applicability of latter being well proven at higher maturities. However, for the correlations of the 2-MP/MCpP ratio, oils biodegraded at 4th stage should be removed from the data set, since at this level of biodegradation 2-MP is altered, which decreases the parameter’s value.
The typical values of MCpPI at different maturity levels are as follows: 2.50 for very mature oils (Rr = 0.95-1.05%).
A novel maturity parameter MCpPI is herewith proposed. It showed statistically significant correlations with many frequently used maturity ratios, and proved its applicability in a wide range of maturity, corresponding to Rr = 0.60-1.05%. Furthermore, it can be used up to the 4th stage of biodegradation. Yet another maturity parameter is introduced here, the 2-MP/MCpP ratio, which is particularly applicable at higher maturities, but can be used only for oils which did not exceed the 2nd stage of biodegradation
Photocatalytic degradation of methyl violet dye using ZnO
No full textMethyl violet (MV) is a widely used cationic dye in industries such as textile, paint, and printing, but it comes with significant environmental and health hazards, including toxicity and potential carcinogenic effects in humans [1]. In recent years, semiconductor photocatalysis has attracted significant interest in pollution control. It is a highly promising and sustainable advanced oxidation technology for wastewater treatment, which offers efficient degradation and complete mineralization of organic pollutants without generating harmful secondary pollution [2]. In this study, ZnO is evaluated for its efficiency in degrading MV dye in an aqueous solution under UV light irradiation at room temperature. The experimental setup consisted of a photoreactor equipped with a cooling system, a magnetic stirrer, and a UV lamp as the light source (Osram Vitalux, 300 W, UVA : UVB = 13.6 : 3, by manufacturer’s data). The entire system was kept in complete darkness to eliminate any interference from ambient light. The reaction suspension was prepared by mixing dye solution (c0 = 10 mg/L) with 10 mg of ZnO catalyst. The suspension was continuously stirred using a magnetic stirrer and irradiated with UV light after 30 min of mixing in dark. During the first 60 min of reaction, 3.5 mL samples were withdrawn from the photoreactor every 10 minutes, followed by sampling every 15 minutes thereafter. Each sample was immediately analyzed using a UV-Vis spectrophotometer (Shimadzu 1800, Japan). The dye degradation kinetic was monitored by measuring the absorbance of the collected samples at 580 nm, the characteristic absorption maximum of MV [3]. Results indicated that photodegradation of MV in the presence of ZnO was successful under applied experimental conditions. After 120 minutes of reaction, 91.6% of the dye was degraded. This promising result creates the possibility for further application of ZnO-based photocatalysts for the degradation of similar cationic dyes
Removal of organic pollutants – mycotoxin ochratoxin A and pharmaceutical ketoprofen by cationic surfactant modified kaolinite
No full textThe potential of kaolin modified with a cationic surfactant - hexadecyltrimethylammonium (HDTMA) bromide as an adsorbent for the removal of two different contaminants: mycotoxin - ochratoxin A (OCHRA) and the pharmaceutical - ketoprofen (KET) from buffer solutions (pH 7) was investigated. The amount of HDTMA used for modifcation was equal to 50% of kaolin’s cation exchange capacity (CEC). The obtained material (HKR-50) was characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry/thermogravimetric analysis (DSC/TG), and scanning electron microscopy (SEM), confirming successful surface modification of kaolinite with HDTMA. Adsorption experiments demonstrated that HKR-50 exhibited significantly enhanced removal efficiency for both OCHRA and KET compared to unmodified kaolin. Nonlinear adsorption isotherms suggested a complex mechanism involving both hydrophobic and electrostatic interactions between contaminants and HDTMA ions. The data fit well to the Langmuir model, with maximum adsorption capacities of 2.57 mg/g for OCHRA and 1.40 mg/g for KET. These findings indicate that surfactant-modified kaolin is a promising and cost-effective adsorbent for the removal of mycotoxins from animal feed and pharmaceuticals from contaminated water, contributing to environmental protection and public health
Carbon footprint calculator as an instrument for faster green transition: case study-glassmaking tradition meets innovation
No full textAccording to the United Nations Framework Convention on Climate Change, the carbon footprint represents climate change
that alters the composition of the atmosphere and is directly or indirectly attributed to anthropogenic activity. Depending on the nature
of the activity, different types of carbon footprint can be identified, considering typical annual greenhouse gas (GHG) emissions. The
individual carbon footprint is based on the consumption habits of the individual and takes into account GHG emissions originating from
the use of means of transport, consumption of electricity for heating and cooling residential (and other) spaces, eating habits,
consumption of goods and services, recycling habits, etc. The carbon footprint of a product includes emissions of harmful gases from
all stages, starting from the extraction of raw materials, the production process, the required energy, the transformation of the product
for the needs of other companies, the habits of customers when using the product and its treatment as waste, as well as transportation
between all production stages. The corporate footprint includes the inventory of greenhouse gas emissions related to the operations of a
particular company. This is the main information basis for identifying both energy efficiency measures at the level of an individual
company and joint activities at the level of the entire sector with the aim of reducing the number of harmful gases emitted into the
atmosphere. As part of the project ""Glassmaking Tradition Meets Innovation"" financed by the Creative Europe Program, it is planned
to create an online carbon footprint calculator for creative practices in the field of handmade glass products/objects. The design and
build calculator allow artists, craftsmen and creative entrepreneurs to work with glass to calculate the carbon footprint of a variety of
hand-crafted creative expressions of glass. The result of the project mentioned will adapt the green paradigm, that is, it will contribute
to the fact that artists and craftsmen in the glass industry become more aware, responsible and equipped for a future without carbon
dioxide. This unique calculator is an innovative tool that will directly enable and widely promote the digital and green transformation
of the creative and artistic production of glass objects through the development of innovative ways of dealing with the environmental
challenges of working with glass and minimizing the impact on the environment. Its original results (in knowledge, technology and art)
could significantly change the quality of work with glass in the EU countries, to increase the number of socially responsible creative
entrepreneurs, craftsmen and artists working with glass, to reduce CO2 emissions and to achieve zero waste production in the field of
handmade glass objects. The methodology of creating the calculator will be based on an interdisciplinary analysis of different types of
glass materials (especially glass waste) and ways of their creative processing. The calculator will be used in the evaluation and design
of sustainable ideas for work based on the application of the circular economy model.Prema Okvirnoj konvenciji Ujedinjenih nacija o klimatskim promenama, ugljenični otisak predstavlja promenu
klime koja menja sastav atmosfere i direktno ili indirektno se pripisuje antropogenoj aktivnosti. U zavisnosti od prirode aktivnosti, mogu
se identifikovati različite vrste ugljeničnog otiska, s obzirom na tipične godišnje emisije gasova sa efektom staklene bašte. Pojedinačni
ugljenični otisak zasniva se na potrošačkim navikama pojedinca i uzima u obzir emisije gasova sa efektom staklene bašte koje potiču
od upotrebe prevoznih sredstava, potrošnje električne energije za grejanje i hlađenje stambenih (i drugih) prostora, navika u ishrani,
potrošnje dobara i usluga, navika recikliranja itd. Ugljenični otisak nekog proizvoda uključuje emisije štetnih gasova iz svih faza, počev
od ekstrakcije sirovina, proizvodnog procesa, potrebne energije, transformacije proizvoda za potrebe drugih kompanija, navika kupaca
prilikom korišćenja proizvoda i njegovog tretmana kao otpada, kao i transporta između svih proizvodnih faza. Korporativni otisak
uključuje inventar emisija gasova sa efektom staklene bašte koji se odnosi na poslovanje konkretnog preduzeća. U pitanju je glavna
informaciona osnova za identifikaciju kako mera energetske efikasnosti na nivou pojedinačnog preduzeća, tako i zajedničkih aktivnosti
na nivou celog sektora sa ciljem da se smanji količina emitovanih štetnih gasova u atmosferu. U okviru projekta „Glassmaking Tradition
Meets Innovation“ finansiranog od strane Programa Kreativna Evropa je planirano kreiranje onlajn kalkulatora ugljeničnog
(karbonskog) otiska za kreativne prakse u domenu ručne izrade proizvoda/predmeta od stakla. Dizajn i izrada kalkulatora omogu ćava
umetnicima, zanatlijama i kreativnim preduzetnicima koji rade sa staklom da izračunaju ugljenični otisak različitih ručno izrađenih
kreativnih izraza od stakla. Rezultat pomenutog projekta će prilagoditi zelenu paradigmu, odnosno doprineće tome da umetnici i zanatlije
u staklarskoj delatnosti postanu svesniji, odgovorniji i opremljeniji za budućnost bez ugljen-dioksida. Ovaj unikatni kalkulator predstavlja inovativni alat koji će direktno omogućiti i naširoko promovisati digitalnu i zelenu transformaciju kreativne i umetničke
proizvodnje predmeta od stakla putem razvoja inovativnih načina suočavanja sa ekološkim izazovima u radu sa staklom i
minimiziranjem uticaja na životnu sredinu. Njegovi originalni rezultati (u znanju, tehnologiji i umetnosti) mogli bi značajno da promene
kvalitet rada sa staklom u zemljama Evropske unije, da povećaju broj društveno odgovornih kreativnih preduzetnika, zanatlija i umetnika
koji rade sa staklom, da smanje emisiju CO2 i da postignu nultu proizvodnju otpada u oblasti ručne izrade predmeta od stakla.
Metodologija izrade kalkulatora će se zasnivati na interdisciplinarnoj analizi različitih vrsta staklenih materijala (posebno staklenog
otpada) i načina njihove kreativne obrade. Kalkulator će se koristiti u proceni i dizajnu održivih ideja za rad koji je zasnovan na primeni
modela cirkularne ekonomije
Thermal decomposition of cerussite
No full textThanks to its distinctive physical properties, lead stands out as one of the most
valuable non-ferrous metals globally. Both pure lead and its alloys are extensively
used across various sectors, including mechanical engineering, radiation shielding,
battery manufacturing, and several other industrial applications [1,2]. In natural
deposits, lead is predominantly encountered as sulphide minerals, such as galena,
and to a lesser extent as carbonate minerals like cerussite. The aim of this study is
the thermal analysis of the dissociation of the mineral cerussite. The analysis is
performed using TGA, DTA and DSC methods, at a heating rate of 5 °C/min. It
was established that PbCO3 first decomposes into PbO. As the temperature rises,
PbO oxidizes, forming Pb2O3. A further increase in temperature leads to a reaction
between Pb2O3 and residual PbO, resulting in Pb3O4. Since the initial sample of
cerusite also contains CaCO3, at the very end of the thermal decomposition, CaCO3
breaks down into CaO, which reacts with Pb3O4 to form Ca2PbO4
Nanostructured Fluorapatite as a Multifunctional Material for Environmental Protection Solutions
No full textNanostructured fluorapatite (Ca₁₀(PO₄)₆F₂), traditionally known as a calcium phosphate-based bioceramic with tunable morphology and surface chemistry, has attracted growing attention in recent years for its multifunctional role in
environmental protection. Owing to its high chemical stability, ion-exchange capabilities, and biocompatibility, fluorapatitebased nanomaterials are increasingly being explored as efficient agents for the removal of environmental pollutants. Recent studies have demonstrated its efficacy in removing heavy metals ions (Pb2+, Cr3+, Fe3+), fluoride, and phosphate through adsorption and ion substitution mechanisms [1-3]. Additionally, nano-FAP has been engineered with photoreactive and luminescent dopants (e.g., Eu3+, Tb3+), enabling its application in the development of selective optical sensors for pH and toxic metal ion detection [4]. Furthermore, the integration of nano-FAP into vanadate-based or agarose-supported nanocomposites has shown promising results in photocatalytic degradation of organic pollutants under light sources [5]. The antimicrobial properties of modified nano-FAP are also well documented [6,7]. These multifunctional properties—adsorptive capacity, photocatalytic activity, luminescence, and biocompatibility—position nano-FAP as a versatile material for sustainable green technologies. However, futhere investigation into the long-term stability, environmental safety, and scalability of these nanostructures is essential to advance their real-world applications. This work provides a comprehesive overview of current trends and outlines key challenges in traslating laboratory-scale findings into practical environmental solutions
Thermally Activated Composite Y2O3-bTiO2 as an Efficient Photocatalyst for Degradation of Azo Dye Reactive Black 5
No full textWater pollution from textile effluents poses serious environmental risks, particularly due to persistent anionic dyes such as Reactive Black 5 (RB5). This study demonstrates that simple deposition of Y2O3 onto commercially available, biobased TiO2 (bTiO2) significantly enhances photocatalytic degradation efficiency under simulated sunlight, suppressing rapid recombination of electron–hole pairs. Addressing a key research gap, the proposed method replaces expensive nanoscale precursors and complex synthesis routes typically used for Y2O3/TiO2 systems with a low-cost, straightforward approach involving weak complexation and co-precipitation. The resulting Y2O3-bTiO2 composite was characterized using FTIR, XRD, SEM, EDX, TEM, XPS, and UV-DRS techniques, confirming efficient incorporation of Y2O3 on the TiO2 surface. Photocatalytic experiments revealed that nanoparticles calcined at 700 °C achieved complete RB5 degradation within 60 min—reducing the reaction time by half compared to undoped bTiO2. Systematic studies of initial dye concentration, catalyst loading, and irradiation time confirmed that the degradation followed pseudo-first-order kinetics with a rate constant of 0.064 min−1 (R2 = 0.98). Calculated quantum yields corroborated the reduced electron–hole recombination induced by Y2O3 deposition. These findings highlight the novelty and practicality of the developed Y2O3-bTiO2 photocatalyst as an efficient, affordable, and environmentally sustainable material for the degradation of industrial dyes
Cleaner Fuel from Coal: Chemical Leaching as a Tool for Environmental Risk Reduction
No full textCoal remains a vital component of the global energy portfolio [1]. However, its utilisation poses significant environmental
challenges. The release of sulfur compounds and fine particulate matter during combustion has raised serious concerns
regarding air pollution, climate stability and the integrity of surrounding ecosystems.
There are several types of coal, each with its specific characteristics and various applications in industry and energy
production. Low-rank coals, such as lignite, are among the most abundant fossil fuels but are characterised by elevated
levels of moisture, ash and sulfur, which render them energetically inefficient and environmentally problematic [2]. These
properties render them less efficient and more polluting compared to higher-grade coals. However, because of their
abundance and economic significance, improving their quality through pre-combustion treatments is a key environmental
priority. Their combustion contributes to the formation of acid rain, accelerates soil and water degradation and exacerbates
long-term ecological harm [3]. In response to these challenges, there is a growing need to develop and implement advanced
coal treatment technologies that aim to reduce pollutant emissions before combustion [4].
These upgrades can be achieved through various innovative methods, including chemical, biological, physical and
electrochemical approaches. By applying such treatments, the environmental footprint of coal use can be significantly
reduced [5]. Among these, chemical leaching, particularly with the use of acidic and oxidative reagents, has proven to be
especially effective in removing sulfur, as well as ash-forming minerals. By decreasing the release of SO₂ and particulate
matter during combustion, these processes facilitate cleaner energy production and support the transition toward more
environmentally friendly energy systems.
This study explores the application of oxidative and acid leaching techniques on lignite samples sourced from Serbian
deposits [6]. The experimental results reveal a marked improvement in coal quality, with significant reductions in sulfur and
ash content. Incorporating such pre-combustion treatments into broader sustainable energy strategies is essential to
minimising environmental damage while maintaining the energy security provided by coal.
Raising awareness of coal's ecological consequences and promoting cost-effective, eco-friendly treatment technologies is
a critical step toward reducing the environmental burden of fossil fuel use and enabling a cleaner energy transition. Such
outcomes emphasise the importance of incorporating pre-combustion treatments into sustainable energy strategies to
mitigate environmental damage