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Exploring wood-derived biochar potential for electrochemical sensing of fungicides mancozeb and maneb in environmental water samples
No full textThe sustainable material, biochar (BC) from a hardwood source, was synthesized via pyrolysis process at 400 ◦C
(BC400) and 700 ◦C (BC700) and used as a modifier during the electrochemical sensor design. The prepared BCs
were characterized by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and
elemental analysis (CHNS). The development of rapid analytical techniques for detecting pesticides employing a
low-cost carbon paste electrode (CPE) modified with BC is a novel strategy to provide a sensitive response to
water pollution. The prepared working electrodes (unmodified CPE, BC400-CPE, and BC700-CPE) were
compared for selected fungicides mancozeb (MCZ) and maneb (MAN) sensing, and BC700-CPE provides the most
favorable analytical response of target analytes. Cyclic voltammetric investigations revealed that the electrode
reaction is irreversible and controlled by the adsorption of MCZ and MAN at the surface of the BC700-CPE, which
led to an optimization of the differential pulse adsorptive stripping voltammetric (DP-AdSV) method. The obtained working linear concentration ranges were 25–2780 μg L− 1 MCZ and 49–1840 μg L− 1 MAN in BrittonRobinson buffer pH 7.0 using CPE modified with 10 % BC700. The evaluated limit of detection was 7.5 μg
L− 1 for MCZ and 15.0 μg L− 1 for MAN. Investigated interferences did not significantly affect the MCZ and MAN
oxidation signal intensity. The developed DP-AdSV method was successfully applied to determine selected
fungicides in spiked river water and wastewater samples, with good recovery and reproducibility
Thermodynamic simulation of fly ash and flotation tailings geopolymerisation process
No full textThis work aims to develop a thermodynamic model for the geopolymerisation process of fly ash (FA) and flotation tailings (FT) with a prediction of the physicochemical composition of the geopolymers based on the initial materials (FT, FA), alkali reagents, and water. Modeling was carried out using the thermodynamic model (Gibbs Energy Minimization Software) GEM-Selektor. The simulation was done for the four compositions of geopolymer mixtures (100%, 80%, 65%, and 50% of FA). The validation of the thermodynamic simulation relies on experimental results. It involves comparing the geopolymerization products predicted by the model with those obtained through experimental quantification. This comparison focuses on the structural and mechanical properties of the geopolymers, specifically using techniques such as Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) and measuring the Unconfined Compressive Strength (UCS) of geopolymer materials for 28 days of curing. The simulation results from the model confirmed an increase in the quantity of C-A-S-H formed with the addition of FT. Additionally, the results indicated that distinguishing between the proportions of C-A-S-H and N-A-S-H is crucial for predicting material stability. According to both the experimental results and the literature, it is important not to exceed the optimal limits for the three parameters studied: Ca/Si, Si/Al, and Na/Al molar ratios. This model can be utilized to predict and enhance understanding of how various parameters affect the final composition of geopolymers. This approach will help minimize the number of trials needed to investigate these parameters and optimize them
Treatment of flue gas and coal to reduce air pollution-overview
No full textThis paper presents the procedures that can be used to reduce air pollution that originates from the burning of fossil fuels. Research has shown that burning coal is the largest source of emissions of greenhouse gases such as carbon dioxide, sulfur oxides, nitrogen oxides and suspended particles. In order to reduce the emission of harmful agents from thermal power plants, several procedures based on various technologies are applied. It is possible to treat the already created flue gases created by burning coal in the classic way, treatment of the coal itself before the start of combustion in the thermal power plant and special procedures for coal treatment. Very effective procedures applied to protect air from pollution in the energy sector are: flue gas desulphurization (FGD), coal purification before the combustion process (coal washing), coal gasification and coal combustion in a fluidized bed. The paper also provides a detailed account of the advantages and disadvantages of the procedures described with an analysis of the contribution of scientific research in defining the technology itself
Optimization of Milling Process Parameters for Waste Plum Stones for Their Sustainable Application
No full textThe impact of milling process parameters on the physicochemical properties of waste plum
stones was investigated to enable their further utilization as a functional material. The
experiments were conducted using a planetary ball mill, with variations in milling duration
(1–3 h), the ball-to-powder ratio (bpr) (10:1 and 20:1), and the rotation speed (250 and
500 rpm). Transformations of material in a function of process parameters were assessed by
XRD, FTIR, and SEM analysis, revealing differences in particle size distribution, functional
group composition, and surface morphology. Optimization of milling process parameters
was focused on promoting fine particle formation and surface activation without causing
significant material degradation. The best result was achieved with the PS-M10 sample,
processed at a speed of 500 rpm and a bpr of 20:1 during a short milling time of 1 h. The
milled sample demonstrated promising potential for further applications, particularly for
heavy metal ion (Pb2+ and Cu2+) removal from aqueous solutions through adsorption
Biomimetic recovery of valuable metals from old flotation tailings in Majdanpek, Serbia, using Aspergillus niger for bioleaching and nanomaterial synthesis
No full textThe accumulation of old flotation tailings in Majdanpek, Serbia, presents significant environmental challenges and highlights the need for innovative, sustainable approaches to metal recovery. This study evaluates the bioleaching potential of the mould Aspergillus niger (A. niger) for extracting valuable metals from these tailings. Utilizing a batch system with A. niger cultivated in soybean broth we investigated its efficiency in leaching copper (Cu), zinc (Zn), manganese (Mn), aluminum (Al), and iron (Fe) under controlled conditions: initial pH 4, temperature 25 °C, and a solid-to-liquid (S/L) ratio of 1:20 (w/v). Over a 35-day period, approximately 45 % Cu, 40 % Zn, 35 % Mn, 5 % Fe, and 3 % Al were extracted from the tailings. Analytical techniques, including X-ray diffraction (XRD), optical microscopy (OM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), confirmed transformations in the mineral phases, with secondary minerals such as oxalates and oxides forming. Field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDS) revealed the degradation of sulfides and carbonates, leading to the formation of oxides and crystallized oxalates on the mineral surfaces. Additionally, FESEM-EDS analysis of the bioleaching liquor identified nano-sized metal-based particles of Cu, Zn, Mn, Al, and Fe. The proposed bioleaching mechanism involves acidolysis, complexolysis, alkaline lysis, and biosorption. This study demonstrates that A. niger offers a viable green technology for both sustainable metal recovery and nanomaterial synthesis from mining tailings, presenting a novel biomimetic approach to utilizing unconventional raw materials
Sustainable Integrated Approach to Waste Treatment in Automotive Industry: Solidification/Stabilization, Valorization, and Techno-Economic Assessment
No full textAn integrated approach to waste management is based on efficient and safe methods for
waste prevention, recycling, and safe waste treatment. In accordance with these principles,
in this study, non-hazardous aluminosilicate waste (dust and sand) was used in the solidification/
stabilization (S/S) treatment of hazardous waste (coating, emulsion, and sludge)
from the automotive industry. Also, the oily component of the waste was valorized and
investigated for energy recovery through co-incineration. The two S/S processes were proposed
and their sustainability was assessed by utilizing all types of waste generated in the
same plant, obtaining stabilized material suitable for safe disposal and oil phases for further
valorization, and by techno-economic analysis. The efficiency of the S/S processes was
evaluated by measuring unconfined compressive strength, hydraulic conductivity, density,
and the EN 12457-4 standard leaching test of S/S products, along with XRD, SEM-EDS, and
TG-DTG analyses. The possibility of using the oil phase was assessed based on its calorific
value. The techno-economic assessment compared the investments, operating costs, and
potential savings of both treatment scenarios. The results show that an integrated approach
enables safe waste immobilization and resource recovery, contributing to environmental
protection and economic benefits
Synthesis, characterization and application of multifunctional biochars based on waste lignocellulosic biomass
No full textIstraživanje u okviru ove doktorske disertacije usmereno je na održivo korišćenje otpada iz
prehrambene industrije u cilju razvoja multifunkcionalnih biočađi. Otpadne koštice voća: breskve
(KB), višnje (KV) i šljive (KŠ), poreklom iz lokalne fabrike voća, pirolizovane su kako bi se
proizvele biočađi KBB, KVB i KŠB, redom. Dobijene biočađi su prosejane na željene granulacije i
detaljno okarakterisane različitim fizičko-hemijskim analizama kao i primenom: SEM-EDX, XRD,
FTIR-ATR, BET i TGA/DTG tehnike. Zahvaljujući velikoj specifičnoj površini, razvijenoj
poroznoj stukturi i prisustvu velikog broja funkcionalnih grupa, sintetisane biočađi su se pokazale
kao efikasni adsorbenti za uklanjanje toksične boje brilijantno zelene (BZ) u šaržnom sistemu. U
cilju optimizacije adsorpcionog procesa, ispitani su procesni parametri, pri čemu su optimalni uslovi
postignuti primenom adsorbenta prečnika 0,5-1 mm, na pH vrednosti 6, dozi adsorbenta od 2 g/L,
vremenu kontakta od 90 min, temperaturi od 35 °C i inicijalnoj koncentraciji boje od 50 mg/L.
Radi boljeg razumevanja mehanizma adsorpcije BZ primenom sintetisanih biočađi,
eksperimentalni podaci su analizirani primenom različitih kinetičkih (pseudo-prvi red, pseudo-drugi
red i Weber-Morrisov model) i izotermnih modela (Langmuirov, Freundlichov i Sipsov model).
Primenjene adsorpcione izoterme, potvrdile su visoke adsorpcione kapacitete biočađi prema BZ, pri
čemu su najviši kapaciteti ostvareni primenom Sipsovog modela: 114,46 mg/g za KVB, 101,11
mg/g za KBB i 100,38 mg/g za KŠB. Da bi se ispitao uticaj mešanja na kinetiku adsorpcije,
eksperiment je dodatno izveden u air-lift reaktoru (ALR) pri dva različita protoka vazduha.
Rezultati su pokazali da je primenom KVB u ALR-u postignuta približno ista efikasnost uklanjanja
BZ kao u šaržnom sistemu, ali za dvostruko kraće vreme, što ukazuje na značajan potencijal air-lift
sistema za efikasno uklanjanje boje uz značajno smanjenje trajanja procesa i energetskih troškova.
Na osnovu eksperimentalno dobijenih rezultata, primenom veštačkih neruonskih mreža,
razvijen je model koji omogućava pouzdano predviđanje adsorpcionog kapaciteta sintetisanih
biočađi prema drugim katjonskim bojama. Model je pokazao dobru tačnost predikcije, čime je
potvrđen potencijal proizvedenih biočađi za širu primenu u tretmanu otpadnih voda.
Pored toga, proizvedene biočađi su hemijski aktivirane i ispitivane kao nosači za imobilizaciju
lakaze iz Trametes versicolor. Uzorak KVB se pokazao kao najefikasniji nosač, a uspešna
imobilizacija lakaze potvrđena je pomoću SEM-EDX i FTIR-ATR analiza. Imobilisana lakaza na
KVB uspešno je primenjena za razgradnju BZ, pri čemu je u šaržnom sistemu postignuta efikasnost
uklanjanja od 93% nakon 4 h, dok je u ALR-u ostvarena efikasnost od 98% za 2,5 puta kraće
vreme. Imobilisana lakaza na KVB pokazala je efikasnost razgradnje boje veću od 80% nakon
devet uzastopnih ciklusa u šaržnom sistemu, što ukazuje na dobru stabilnost imobilisanog enzima
na biočađi.
Rezultati ove doktorske disertacije ukazuju da se otpad iz prehrambene industrije može
prevesti u multifunkcionalne biočađi, koje su se pokazale kao ekološki prihvatljivi i ekonomski
isplativi adsorbenti i nosači za imobilizaciju enzima. Pretvaranjem otpada iz prehrambene industrije
u biočađ, ne samo da se smanjuje njegovo taloženje po deponijama, već se istovremeno doprinosi i
ostvarivanju principa cirkularne ekonomije kroz razvoj novih proizvoda visoke upotrebne vrednosti
sa širokom potencijalnom primenom u različitim oblastima.The research presented in this doctoral dissertation focuses on the sustainable utilization of food industry waste for the development of multifunctional biochars. Waste fruit stones from peach (KB), sour cherry (KV), and plum (KŠ), obtained from a local fruit processing factory, were pyrolysed to produce the biochars KBB, KVB, and KŠB, respectively. The obtained biochars were sieved to the desired particle sizes and thoroughly characterized through various physico-chemical analyses, as well as: SEM-EDX, XRD, FTIR-ATR, BET, and TGA/DTG techniques. Owing to their high specific surface area, highly developed porous structure and the presence of numerous surface functional groups, the synthesized biochars demonstrated high efficiency as adsorbents for the removal of the toxic dye Brilliant Green (BZ) in a batch system. In order to optimize the adsorption process, various operational parameters were investigated, and the optimal conditions were achieved using an adsorbent with a particle size of 0.5-1 mm, at pH value of 6, an adsorbent dose of 2 g/L, a contact time of 90 min, a temperature of 35 °C, and an initial dye concentration of 50 mg/L.
To gain a better understanding of the adsorption mechanism of BZ using the synthesized biochars, experimental data were analyzed using various kinetic (pseudo-first order, pseudo-second order and Weber–Morris model) and isotherm models (Langmuir, Freundlich, and Sips models). The applied adsorption isotherms confirmed the high adsorption capacities of the biochars for BZ, with the highest capacities obtained using the Sips model: 114.46 mg/g for KVB, 101.11 mg/g for KBB, and 100.38 mg/g for KŠB. To examine the influence of mixing on adsorption kinetics, the experiment was additionally conducted in an air-lift reactor (ALR) at two different air flow rates. The results showed that the use of KVB in the ALR achieved approximately the same BZ removal efficiency as in the batch system, but in half the time, indicating the significant potential of the air-lift system for efficient dye removal with substantial reductions in both process duration and energy consumption.
Based on the experimentally obtained results, the model was developed using artificial neural networks to enable reliable prediction of the adsorption capacity of the synthesized biochars for other cationic dyes. The model demonstrated good predictive accuracy, confirming the potential of the produced biochars for broader application in wastewater treatment.
In addition, the produced biochars were chemically activated and investigated as carriers for the immobilization of laccase from Trametes versicolor. The KVB proved to be the most efficient carrier, and successful laccase immobilization was confirmed using SEM-EDX and FTIR-ATR analyses. The immobilized laccase on KVB was successfully applied for the degradation of BZ, achieving a removal efficiency of 93% after 4 hours in the batch system, while in the ALR, an efficiency of 98% was achieved in 2.5 times shorter duration. The immobilized laccase on KVB retained more than 80% degradation efficiency after nine consecutive cycles in the batch system, indicating good stability of the immobilized enzyme on the biochar.
The results obtained in this doctoral dissertation indicate that food industry waste can be converted into multifunctional biochars, which have proven to be both environmentally friendly and economically viable as adsorbents and carriers for enzyme immobilization. Converting food processing waste into biochar, not only is landfill disposal reduced, but the principles of the circular economy are also supported through the development of new high-value products with broad potential applications across various fields
Bentonites modified with surfactants in the removal of non-steroidal anti-inflammatory drugs from water
No full textНестероидни антиинфламаторни лекови (НСАИЛ) доспевају у животну средину током њихове производње, употребе и одлагања, угрожавајући на тај начин водене екосистеме. Они представљају значајан еколошки проблем јер се не уклањају ефикасно конвенционалним методама које се користе у постројењима за пречишћавање вода. Стога је неопходно развити нове методе за третман отпадних вода. Адсорпција се издваја као ефикасна, економична, еколошки прихватљива и једноставна метода. Модификовани природни минерали, као што су глине (бентонит, каолин) и зеолити, показују високу ефикасност у уклањању НСАИЛ из водених средина, пружајући могуће решење овог проблема. У овом раду приказан је преглед резултата истраживања уклањања НСАИЛ на бентонитима модификованим различитим сурфактантима.Non-steroidal anti-inflammatory drugs (NSAIDs) enter the environment during their production, use, and disposal, thereby threatening aquatic ecosystems. They represent a significant environmental issue because they are not effectively removed by conventional methods used in wastewater treatment plants. Therefore, it is necessary to develop new methods for wastewater treatment. Adsorption stands out as an efficient, economical, environmentally friendly, and simple method. Modified natural minerals, such as clays (bentonite, kaolin) and zeolites, have shown high efficiency in removing NSAIDs from aquatic environments, offering a potential solution to this problem. This paper presents a review of research results on the removal of NSAIDs using bentonites modified with various surfactants
Metal exclusion and physiological plasticity shape orchid success across diverse geologies
No full textEdaphic stress is a major factor influencing plant fitness, yet it remains insufficiently understood, especially in rare species like orchids. Orchids, with their complex ecological requirements and sensitivity to soil chemistry, provide valuable models for studying adaptations to contrasting geologies. We investigated the ecophysiological responses and elemental accumulation strategies of two terrestrial orchids — Gymnadenia conopsea and Dactylorhiza sambucina — growing on carbonate, ultramafic, and siliceous substrates in the Central Balkans. Despite differences in phylogeny and ecology, both species showed strikingly similar patterns of elemental partitioning. Macroelements (Ca, Mg, K, and P) consistently accumulated in the above-ground organs, particularly in leaves and inflorescences, while most trace elements (Cr, Co, Ni, Fe, and Mn) were retained in the roots, indicating an exclusion-based tolerance strategy. However, D. sambucina exhibited a notable capacity for Zn and Cu accumulation in shoots, suggesting species-specific flexibility in metal handling. Physiological analyses revealed that individuals from carbonate soils exhibited the lowest stress levels, as indicated by higher photosynthetic pigment concentrations, whereas plants from ultramafic sites showed elevated antioxidant activity and accumulation of phenolics and lipid peroxidation products, reflecting a stronger stress response. These findings demonstrate that exclusion remains the dominant metal tolerance mechanism in terrestrial orchids, but species-specific physiological adjustments and selective metal accumulation strategies contribute to their successful establishment on chemically contrasting substrates
The significance of the circular economy in solid waste management
No full textThe article shows the importance of applying the circular economy strategy in the field of
solid waste management. The circular economy was analyzed as a model of economic development
that deals with the restructuring and modernization of the economic system in accordance with the
laws that regulate the circulation of materials and the flow of energy in the natural ecological
system. It was pointed out the importance of accepting this concept at the global and local level,
because this way a great contribution is made in solving the issue of environmental protection. It
was pointed out that the best model for the development of a circular economy is a production
method in which people live in harmony with the ecosystem. The dynamics of ecological
productivity, also known as ecodynamics, promotes the harmonious exchange of information,
energy and materials between people and nature. Also, the article shows the procedures for solid
waste management, depositing and recycling, with the advantages and disadvantages indicated.
The main goal of the circular economy is apostrophized, which is to limit the disposal of solid waste
in landfills and to encourage an increase in the rate of its separation, recycling and conversion into
circulating material