Faculty of Technology and Metallurgy

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Electrochemical sensors based on polymer-modified screen-printed graphene electrodes for the detection of pharmaceuticals in aquatic environments
(SAGE Publications, 2025-10-06)
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Paunović, Perica
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Detecting contaminants in aquatic environments, including wastewater and natural water bodies, is essential for safeguarding environmental health and ensuring water quality. Pharmaceuticals, often incompletely metabolised by humans and animals, persist in the environment and pose risks to ecosystems due to their bioactivity and accumulation potential. Water, as a vital resource for all industries, including mineral and metallurgy, faces increasing challenges from pollutants, making advanced detection methods crucial. This study investigates the application of polymer-modified screen-printed graphene electrodes for the sensitive detection of doxorubicin. The use of graphene not only in energy storage devices but also in sensors makes such materials important for a green and sustainable economy. Electrode performance was evaluated at three pH levels, within a linear concentration range from 1.5 to 7.4 µmol L−1. The electrodes’ excellent stability and enhanced sensitivity highlight their potential as cost-effective and rapid tools for monitoring pharmaceutical residues in aquatic environments, contributing to pollution management and environmental protection.
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REDUCING THE BAND-GAP ENERGY OF TiO2 AS A CRUCIAL OBJECTIVE IN GREEN PHOTOCATALYSIS
(Ss Cyril and Methodius University in Skopje, Faculty of Technology and Metallurgy, 2025-06-12)
Perica Paunović, Anita Grozdanov, Petre Makreski, Martin Stojčevski, Kiril Stoimčev, Gorazd Čepiševski
Green photocatalysis focuses on developing processes to address various environmental challenges, such as the treatment of contaminated water and air, the generation of renewable energy, biomass management, carbon monoxide oxidation, and organic synthesis. TiO2 nanoparticles are relatively inexpensive, non-toxic, and chemically stable. They are available in diverse structural forms and exhibit unique semiconductive properties, making them the most widely utilized photocatalysts in this domain. TiO2 has a wide array of applications in green photocatalysis, including i) photocatalytic remediation and ii) the development of alternative, sustainable energy sources. A significant challenge in modern green photocatalysis is the reduction of the band gap energy (Eg), which is essential for determining the suitability of materials for photocatalytic activity. Decreasing Eg enables TiO2 to effectively harness visible light rather than being limited to ultraviolet light. This study investigates the structural changes and subsequent reduction in Eg resulting from two types of TiO2 modification: i) ionizing irradiation and ii) the incorporation of carbon nanotubes. We synthesized TiO2 nanoparticles using our proprietary sol-gel method, followed by thermal treatment at 400 °C. Structural changes were analyzed using X-ray powder diffraction (XRPD) and Raman spectroscopy, while the band gap energy of the samples was assessed through UV-Vis spectroscopy.
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Polymer-modified screen-printed electrode-based electrochemical sensors for doxorubicin detection
(The Association of South-East European Electrochemists (ASEEE), 2025-02-27)
Iva Dimitrievska, Perica Paunovikj, Anita Grozdanov
In the last decade, intensive research has been performed in the field of analytical electrochemistry, seeking designs of electrochemical sensors capable of providing better analytical characteristics in terms of sensitivity, selectivity, reliability, ease of fabrication and use, and low cost, especially for pharmaceutical drug monitoring. Our research has primarily focused on developing screen-printed electrode-based sensors and their application as electrochemical platforms for drug determination and monitoring, specifically emphasizing their suitability for surface modification. A commercial screen-printed graphene electrode was used as the electrochemical sensing component, which was subsequently modified with polymers, such as polyvinylidene fluoride and chitosan. All studied electrodes were tested using a doxorubicin hydrochloride (DOX) solution with a concentration of 0.002 mol L-1 dissolved in 0.1 mol L-1 phosphate-buffered saline at pH 6.7. Cyclic voltammetry was used as an electrochemical characterization technique to gather data on all tested electrodes' electrochemical activity. The morphological characterization of the electrodes was done using scanning electron microscopy. The changes in the electrolyte during the electrochemical measurements were followed through ultraviolet-visible spectroscopy. The modified electrodes demonstrated a favorable electrochemical response to DOX and exhibited higher electrical conductivity than the commercial one. The characterization results indicated that the Ch-modified electrode exhibited excellent electrochemical conductivity and demonstrated strong electrochemical performance. The evaluations of this electrode comprised the definition of the lowest limit of detection and limit of quantification among the tested electrodes, with values of 9.822 and 32.741 µmol L-1, respectively, within a linear concentration range from 1.5 to 7.4 µmol L-1. Additionally, the electrodes showed excellent repeatability, stability, and reproducibility, confirming their suitability for sensitive DOX detection.
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Influence of irradiation treatment on sensing performances of screen-printed electrodes aimed for doxorubicin monitoring
(Association of South-East European Electrochemists (ASEEE), 2025-05-05)
Perica Paunovikj, Iva Dimitrievska, Marija Katerina Paunovikj, Marija Mitevska, Anita Grozdanov
The subject of study is the development of nanosensors based on carbon nanotubes (CNTs) and polyaniline (PANI) aimed at effective detection and monitoring of doxorubicin - a chemotherapy drug used in the treatment of different types of cancer. The main goal is the design of nanosensors that provide precise and reliable detection and monitoring of doxorubicin, providing an effective approach to monitor drug levels during treatment. The research was carried out on the screen-printed electrodes (SPE) with a working electrode of commercial CNTs and PANI and their modification by irradiation with electron irradiation (50 kGy). The structural changes resulting from the e-beam irradiation were observed by scanning electron microscopy, Raman and FTIR spectroscopy, and thermogravimetric analysis. An electrochemical study employing cyclic voltammetry was done to characterize and test the performance of the nanosensors. Modification with electron irradiation was shown as an effective approach to improve the sensing characteristics of the studied SPE, resulting in a lower limit of detection for the modification. The irradiated SPEs exhibit a limit of detection of 12.674 µmol L⁻¹ for the modified multi-walled CNT (MWCNT) electrode and 12.712 µmol L⁻¹ for the modified PANI electrode, compared to 12.773 µmol L⁻¹ for the MWCNT and 12.712 µmol L⁻¹ for the PANI commercial electrodes.
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Characterization of Al-Containing Industrial Residues in the ESEE Region Supporting Circular Economy and the EU Green Deal
(MDPI AG, 2024-12-20)
Fidanchevski, Emilija
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Šter, Katarina
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Mrak, Maruša
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Rajacic, Milica
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Koszo, Bence David
The increase in industrial waste generation presents a global problem that is a consequence of the needs of modern society. To achieve the goals of the EU Green Deal and to promote the concept of circular economy (CE), the valorization of industrial residues as secondary raw materials offers a pathway to economic, environmental, energetic, and social sustainability. In this respect, Al-containing industrial residues from alumina processing (red mud), thermal power plants (fly ash and bottom ash), and metallurgy (slag), as well as other industries, present a valuable mineral resource which can be considered as secondary raw materials (SRMs) with the potential to be used in construction, supporting the concept of circular economy. This paper focuses on the characterization of 19 secondary raw materials from the East South-East Europe (ESEE) region regarding their physical, chemical, mineralogical, and radiological characteristics. The goal is to provide a foundation for future innovations based on secondary raw materials, in alignment with the EU Green Deal and the principles of circular economy. The results showed that fly ash has the potential to be the best material among those analyzed to be used in the cement industry, mainly due to its favorable radiological and mineralogical properties. However, it is important to control the amount of free lime in the mixture, ensuring it remains below 10%. After evaluating secondary mineral raw materials for metal recovery, the results indicate that these materials are not viable sources for base metals or other technology-critical metals, such as REEs.
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Voltammetric Detection of Diclofenac with Screen-printed Electrodes Based on Graphene and PVDF-Modified Graphene
(The Croatian Society of Chemical Engineers – CSCE, 2024-07-15)
Perica Paunovic
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Anita Grozdanov
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Iva Dimitrievska
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Ana Tomova
In recent years, the detection and determination of numerous drugs and pharmaceuticals in various media have become crucial aspects of modern healthcare and environmental management. Among the available sensing techniques, electrochemical methods, particularly those utilising screen-printed electrodes (SPEs) and different portable equipment have emerged as rapid, effective, sensitive, and inexpensive. This study focuses on the detection of the anti-inflammatory drug diclofenac in neutral media. Cyclic voltammetry measurements were conducted to identify diclofenac and determine the kinetics and electrochemical mechanism of its oxidation, along with assessing the surface characteristics of the employed SPEs. Graphene and modified graphene SPEs were explored as nanosensors for this purpose. The surface of the graphene SPE was modified using polyvinylidene fluoride, applied through a drop modification procedure. The morphology of the examined SPEs was observed by means of scanning electron microscope, while the electrolyte (0.1 g of diclofenac per litre of phosphate-buffered solution, pH = 7.4) was analysed using UV-Vis spectroscopy. The results indicate that the studied SPEs exhibit promising potential for the detection of diclofenac.
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Influence of baking time and formulation of part-baked wheat sourdough bread on the physical characteristics, sensory quality, glycaemic index and appetite sensations
(Frontiers Media SA, 2024-06)
Temkov, Mishela
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Rocha, João Miguel
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Rannou, Cécile
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Ducasse, Maren
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Prost, Carole
Raw materials and process parameters in bread production can modulate the glycemic index, which on itself has been linked with provision of better hunger satisfaction and maintaining better satiation. The objective of this research was to investigate if using unrefined wheat flour or the addition of intact cereals in formulation or alternating the baking time would have an effect on physical characteristics, sensory quality, glycaemic index and appetite sensations in wheat sourdough bread. In the study, three types of commercial part-baked frozen sourdough bread, baked to the final baking for two different times (long and short baking time) were used. A randomized controlled crossover trial was performed with 10 healthy adults who consumed sufficient quantity of bread to ingest 50 g available carbohydrates. Participants self-reported appetite sensations (desire to eat, hunger, fullness, satisfaction, appetite) on a 10 cm visual analog scale (VAS) scale in a course of 180 min. In addition, bread products were subjected to overall acceptability and different sensory attributes were examined on JAR "just about right" scale. Different bread formulations (refined flour, unrefined wheat flour, cereal flour or intact cereals) and different length of baking time significantly influenced (p < 0.005) physical, textural and sensory features of products. The alternation of aforementioned parameters decreased the glycemic index, but not significantly (p > 0.005). No correlation was found between lower GI, satiety and satiation. Liking score and incremental area under the curve (iAUC) of satiety and satiation were calculated as highest in sourdough bread with added cereals.
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Synthesis and Characterisation of Nano Zero-Valent Iron for the Reduction and Immobilisation of Cr(VI) in Water Resources
(The Croatian Society of Chemical Engineers – CSCE, 2025-03-15)
Martin Stojchevski, Stefan Kuvendziev, Zoran Bozinovski, Petre Makreski, Perica Paunović, Mirko Marinkovski, Kiril Lisichkov
Nano zero-valent iron (nZVI) was synthesised through the chemical reduction of Fe(III) ions using iron(III) chloride and sodium borohydride solutions under atmospheric conditions. Structural and chemical characterisation of nZVI was performed using scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), energy dispersive X-ray fluorescence spectrometry (EDXRF), thermogravimetric/differential thermal analysis (TGA/DTA), specific surface area analysis (SSA), and ultraviolet-visible spectroscopy (UV/Vis). The synthesised iron exhibited a zero oxidation state and a nearly one-dimensional morphology. The zero-valent iron nanoparticles with a body-centred cubic crystal structure remained chemically stable for several months. The mean diameter of individual nanoparticles was less than 60 nm, with an SSA of 23.79 m2 g–1. The synthesised nZVI was applied for the catalytic reduction of Cr(VI) in an aqueous solution. The effects of contact time and initial nZVI concentration on the efficiency of Cr(VI) removal from aqueous solution were investigated. The removal efficiency reached 44.2, 74.6, and 94.5 % after 300 min at initial nZVI concentrations of 20, 40, and 60 mg l–1, respectively. This study suggests that the obtained nZVI is an environmentally friendly and effective reducing agent for treating wastewater and groundwater contaminated with hexavalent chromium.
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DETERMINATION OF WORKING STYLES OF STUDENTS OF TECHNOLOGY AT THE FACULTY OF TECHNOLOGY AND METALLURGY IN SKOPJE IN RELATION TO CURRICULUM CHOICE
(KNOWLEDGE – International Journal, 2023)
Ana Tomova
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null, null
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Beti Andonovic
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Kiril Lisickov
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Aleksandar Dimitrov
The purpose of this paper is to examine the benefits and drawbacks of Working Styles in a broad sense, with a focus on identifying and interpreting the dominant Working Styles among students of technology in various curricula at The Faculty of Technology and Metallurgy in Skopje. This research included Julie Hay's questionnaire to determine students’ Working Styles. The objective was to identify characteristics that are reflected through specific Working Styles and their combination, representing a distinct pattern of expected behaviors, known as the script pattern. These findings were summarized for each group of students of technology in five different curricula and subjected to a detailed analysis. The advantages and disadvantages of the identified Working Styles were determined, and essential steps to enhance the benefits and minimize the drawbacks were outlined. Additionally, recommendations were provided to motivate students to further utilize their potential. The study established a connection between the demonstrated Working Styles of student groups and their choice of curriculum. The intention of this research is to contribute to the improvement of curricula and teaching methods, ultimately benefiting current and future students.
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Nano-structured Electrode Materials with Reduced Amount of Platinum Aimed for Hydro gen Evolution. Part I: Effect of cobalt
(INTERNATIONAL SCIENTIFIC JOURNAL "INDUSTRY 4.0", 2023)
Perica Paunovic
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null,null
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Ana Tomova
The subject of this study is electrochemical and structural characterization of nano-dimenzioned composite electrode materials for hydrogen evolution consisted of Co, Pt or CoPt metallic phase and TiO2, both grafted on multiwalled carbon nanotubes (MWCNTs) as a support material. The main idea was to replace platinum entirely or to some extent as an electrode material. The electrode materials with different The common composition of the studied electrode materials was 10%Me + 18%TiO2 + MWCNTs, where Me = Pt, CoPt (1:1, wt.), CoPt (4:1, wt.) and Pt. The structural and surface changes, as well as their influence on electrocatalytic activity were analyzed by means of XRD, TEM, SEM and FTIR. It was found that Co considerably reduces Pt particle size, from 11 nm (in pure Pt metallic system) to 3–4 nm (in mixed CoPt systems). This is a reason for better activity of the electrode material with CoPt (1:1) metallic phase than that with pure Pt, while the CoPt (4:1) with very low quantity of Pt approaches the acitivity of the electrode material with pure Pt.

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