Journal of Chemical Technology and Metallurgy

NAPHTHALENE AND PHENANTHRENE BIODEGRADATION BY ANTARCTIC SOIL - ISOLATED ASPERGILLUS FUMIGATUS STRAINS

2025-06-26T04:47:53+00:00

This article describes the experiments with the two investigated fungal strains isolated from soils on Livingston Island, Antarctica. Our studies by gas chromatography - mass spectrometry (GC - MS) analyses showed the ability degree of the strains to degrade low molecular weight polyaromatic compounds such as naphthalene and phenanthrene. The different degradation capacity of both strains towards each one of the compounds studied was established. The amount of naphthalene in the medium decreased by 44 % during the 9 days cultivation of Aspergillus fumigatus AL3, while it decreased by 37 % when grown in a medium inoculated with Aspergillus fumigatus AL9. The strain A. fumigatus AL3 was able to reduce the phenanthrene amount in the medium by 44.5 %, whereas A. fumigatus AL9 reduced it by a significant 90.5 % under the same conditions and the same period. Some of the intermediates, such
as naphthalene - 1, 2 - diol, 2 - hydroxybenzaldehyde, 2 - hydroxybenzoic acid, naphthalene - 1 - ol, benzene - 1, 2 - dicarboxylic acid, and benzene - 1, 2 - diol, in the catabolite chain of both compounds were also identified. They are typical for the biodegradation of the investigated compounds also with the help of other types of microorganisms.

GREEN SYNTHESIS AND CHARACTERIZATION OF TiO2 NANOPARTICLES USING BIO-WASTE EXTRACTS FOR PARACETAMOL PHOTODEGRADATION

2025-10-02T14:23:57+00:00

Pharmaceutical residues such as paracetamol are increasingly detected in aquatic environments, posing ecological risks and demanding sustainable removal strategies. In this study, TiO₂ nanoparticles were synthesized via a green route using bio-waste such as avocado peel, petai pod, and pomelo peel ethanol extracts as natural capping and stabilizing agents. FT-IR analysis confirmed the presence of phenolic and flavonoid groups, while UV-DRS revealed slight variations in band gap energy (3.18 - 3.27 eV), with TiO₂-EEPPo exhibiting the narrowest band gap. XRD patterns showed that all samples were dominated by the anatase phase with crystallite sizes of 9.9 - 17.7 nm, and FE-SEM/PSA analysis demonstrated nanoscale particle sizes (23 - 98 nm) with porous but agglomerated
morphologies. Zeta potential values (-17.11 to -24.16 mV) indicated sufficient colloidal stability, while adsorption studies highlighted improved affinity in biowaste-modified TiO₂ due to hydroxyl, carboxyl, and phenolic groups. Photocatalytic degradation experiments demonstrated that photolysis alone removed only 36.52 % of paracetamol after 180 min. Biowaste-modified catalysts also exhibited high efficiencies, with TiO₂-EEPA, TiO₂-EEPPi, and TiO₂-EEPPo degrading 91.75 %, 90.1 %, and 95.89 %, respectively, under UV irradiation. These findings confirm that agro-waste-derived extracts not only enhance the structural and photocatalytic properties of TiO₂ but also provide an eco-friendly approach for pharmaceutical wastewater remediation and bio-waste valorization.

SYNTHESIS AND APPLICATION OF BIS-NAPHTHALIMIDE DYE CONTAINING UV ABSORBER AND POLYMERIZABLE GROUPS

2025-10-16T04:31:46+00:00

New bis-naphthalimide dye (BND), containing an UV absorber and two unsaturated allylic groups in its molecule has been synthesized. It was evaluated for applicability on polyamide fibres and sample with intensive yellow-orange colour and yellow fluorescence has been obtained. The degree of exhaustion and fixation were assessed. The colour characteristics and optical properties from the CIE Lab colour space have been examined of the textile sample. The photostability of the dye in solution, as well as of dyed textile material was determined. The possibility for copolymerization of the dye with methyl methacrylate has been investigated and a polymethyl methacrylate with intensive colour and fluorescence has been obtained. It was spectrophotometrically estimated that 82 % of the initial amount of the compound was chemically bonded in the copolymer. Results obtained lead to the conclusion that the synthesized dye have good photostability and can be applied both as fluorescent dye for dyeing of polyamide fibres and as colour fluorescent monomer for obtaining of coloured polymethyl methacrylate.

SYNTHESIS AND ANALYSIS OF THE PROPERTIES OF FATTY ACID AMIDES OF LINSEED OIL

2025-03-18T07:48:53+00:00

In the recent years, interest in obtaining and studying surfactants synthesized from natural raw materials, has been increased. Flaxseed oil, rich in polyunsaturated fatty acids, is a significant object of study in this field. The synthesis and analysis of the properties of amides derived from linseed oil are important for understanding their potential applications in industry. Previously published studies claimed that the amidation of linseed oil fatty acids is possible only with the use of diethanolamine. However, new research has shown that in addition to diethanolamine, diethylamine can also be successfully used for this process. This discovery opens new prospects for the synthesis of fatty acid amides of linseed oil and expands the possibilities of research in this area.

ENHANCED PERFORMANCE OF DSSCs USING Ag-DOPED ZnO THIN FILMS SYNTHESIZED BY SUCCESSIVE IONIC LAYER ADSORPTION AND REACTION METHOD

2025-05-12T02:54:56+00:00

Pure ZnO thin films and Ag doped ZnO (Ag:ZnO) thin films are successfully synthesized using low-cost method. SILAR (Successive Ionic layer Adsorption and reaction) technique is also very easy and simple. The dopant amount is further optimized by varying Ag percentages and investing corresponding optical properties. For 6 wt. % Ag:ZnO, maximum red shift is observed (from 372 to 400 nm). Band gap is also observed to be altered with maximum reduction achieved for 6 wt. % Ag:ZnO thin film (from 2.99 eV for pure ZnO to 2.7 eV). Consequently, optimum (6 wt. %) Ag:ZnO thin film is further used as photoanode in dye sensitized solar cell (DSSC). Additionally, low-cost dye is used in place of expensive dyes used generally in DSSCs. Further structural and morphological characterization of optimum (6 wt. %) Ag:ZnO thin film is also carried over by X-ray diffraction (XRD) and scanning electron microscopy
(SEM). Prepared films are observed to be polycrystalline and hexagonal in structure. DSSC made of Ag:ZnO thin film along with inexpensive dye could yet lead to reasonable conversion efficiency. Furthermore, reasonable increment in efficiency (50 %) is achieved compared to DSSC made with pure ZnO film.

CONVERSION OF ALGAL BIOMASS VIA PYROLYSIS PROCESS INTO PYRO-CHAR PRODUCTION AT WASTEWATER TREATMENT NRC BAIJI

2025-07-11T01:51:48+00:00

Herein, the algal biomass (AB) was crushed for converted into sustainable, renewable as alternative fuel (pyro-char) by pyrolysis processes during effect of reaction temperatures and contact times. The pyrolysis processes accord by drying AB at 105°C for 24 h to ensure the dried status. In this experiment the range of temperatures by 5g of OS-AB, 5 L h-1 flow rate of N2 pressure, with a fixed residence time of 60 min, and a range of temperatures of 300, 500, and 700°C, were called (AB@60min-300°C, AB@60min-500°C, and AB@60min-700°C) respectively. Optimum pyro-char was produced at 60min, 500°C. At the range of duration times with fixed temperature at 500°C optimum temperature was found in the previous run, and the range of the residence time of 30, 60, and 90 min, were called (AB@500°C-30min, AB@500°C-60min, and AB@500°C-90min) respectively. Optimal pyro-char created at 500°C for 90 min. The energy characteristics of AB and pyro-chars comprised high heating value (HHV), proximal and ultimate analysis, energy recovery (ER), energy yield (EY), atomic ratio, and fuel ratio (FR). The findings revealed that AB had the highest carbon content and HHV. Despite the presence of contaminating components, AB pyrolysis might provide pyro-char (solid carbon fuel) for electricity generation at NRC Baiji.

ASSESSMENT OF TOXIC METAL IONS REMOVAL BY NOVEL NANOPOROUS BIO-CHARS

2025-07-27T19:02:35+00:00

Novel nanoporous bio-chars with well-developed mesoporous structure, derived from juice industry residues, are obtained by applying new energy-saving treatment method. Using a precursor with a significantly high content of cellulose, hemicellulose, and lignin (cherry stones) results in the formation of carbonaceous material with micro- and mesopores, whereas a raw material with a higher content of lipids and lignin (dried aronia fruit residue) produces carbon with narrow microporosity. The cadmium adsorption capacity values for activated carbon from cherry stones and aronia residue are 93 and 70 mg g^-1, and mercury adsorption capacities are 83 and 104 mg g^-1, respectively. The characteristics of the obtained nanoporous bio-chars indicate that they are suitable for the removal of highly toxic
metal ions from wastewater.

AGROECOLOGICAL TOURISM AND GENERATED PUBLIC VALUE: THE CASE OF MASSERIA CASACAPANNA IN CHIEUTI (APULIA)

2025-11-20T16:44:14+00:00

In Italy, rural tourism has become an increasingly important form of sustainable development, capable of combining economic, environmental, social, and cultural objectives. This study examines the principles of agroecology applied to rural tourism, analysing the generated public value. Specifically, the case of Masseria Casacapanna, a multifunctional agritourism farm, is analysed through qualitative and quantitative data obtained through a structured questionnaire administered to the managers. The results show that the agro-ecological practices significantly contribute to the creation of Public Value by generating equitable and sustainable well-being in the region: they create local employment, support local economic networks, preserve traditions, and reduce environmental impact
through innovative agro-economic practices. In conclusion, we emphasize the need to integrate the assessment of these impacts into territorial planning decision-making processes and rural development strategies, in line with the national objectives of Equitable and Sustainable Well-being.

STUDY OF THE STRUCTURE AND SURFACE MORPHOLOGY OF ACTIVATED CARBON FROM BLACK CUMIN SEED MEAL (Nigella sativa L.)

2025-08-25T08:08:30+00:00

The present study explores the potential of black cumin seed meal (Nigella sativa L.) (a by-product of industrial oil extraction) to produce activated carbon. The meal was carbonized at 500°C and chemically activated with 85 % H₃PO₄ at 500°C for 1 h. The obtained materials were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and elemental analysis (C, H and N). FT-IR spectra revealed the formation of a carbonized structure with surface oxygenated and phosphate functional groups. SEM micrographs provided a visual indication of a developed surface morphology with finely distributed pores; however, this observation does not substitute for a quantitative pore structure analysis such as N₂-sorption/BET. The obtained results confirm that black cumin seed meal can be used as a promising material for activated carbon production under phosphoric acid activation.

STRUCTURE AND OPTICAL CHARACTERISTICS OF GLASSES IN THE TeO2-BaO-Bi2O3-B2O3 SYSTEM

2025-11-26T15:44:49+00:00

A series of glasses in the BaO-TeO₂-Bi₂O₃-B₂O₃ system, was prepared by melt quenching technique. The amorphous nature of the obtained glasses was confirmed by X-ray powder diffraction analysis. The experimental densities were found to be in the range 5.170 to 5.831 g cm-³. Key structural parameters, including molar volume, oxygen packing density, optical basicity, interionic interaction parameter, and single bond strength, were evaluated to understand the compositional effects on the glass network. Structural characterization using infrared and Raman spectroscopy further elucidated the bonding and vibrational features of the glasses. The refractive indices were measured experimentally and compared with theoretical values calculated using the polarization approach, revealing a strong correlation between experimental and theoretical results.

THERMODYNAMIC SUBSTANTIATION OF PRODUCING SILICON-CONTAINING FERROALLOYS FROM PERLITE

2025-07-01T05:24:21+00:00

Perlite, which is quite widely used in various industries (construction, oil, chemical, food, agriculture and several other industries) due to the content of amorphous silica, which has increased reactivity, can become a reserve raw material for producing silicon-containing ferroalloys. The article presents the results of studies on the possibility of producing ferrosilicon and ferrosilicoaluminium from perlite in the presence of iron and carbon. The studies were carried out by thermodynamic modelling using the HSC-6.0 software package, as well as by methods of rotatable planning and geometric optimization. The conditions (temperature, amount of iron) have been determined that allow the extraction of 75 - 80 % of silicon into FeSi45 grade ferrosilicon (41.3 - 42.2 % of Si) and into FSA5510 grade
ferrosilicoaluminium, containing 51.8 - 52.2 % of Si and 7.5 - 8.8 % of Al.

EXPERIMENTAL BENEFICIATION APPROACH TO IMPROVE PERFORMANCE OF BRICK RECYCLED AGGREGATE IN CEMENT MORTAR

2025-04-10T02:32:47+00:00

The increasing volume of construction and demolition waste (CDW) poses significant environmental challenges, necessitating effective recycling strategies to promote sustainable development in the construction sector in India. This paper examines the current state of CDW management, particularly focusing on brick waste, which is a major contributor to the overall waste generated in country. The study explores experimental techniques to enhance the properties of recycled aggregates, including water absorption and efflorescence tests, conducted according to established IS codes. From CDW, brick waste was derived as fine aggregates. Prior literature results indicated that brick aggregates (BA) exhibit higher water absorption due to their porous structure, highlighting the need for effective treatment methods. Different surface treatment slurries, such as cement, fly ash, and ground granulated blast-furnace slag (GGBS), were applied considering the Beneficiation approach to brick aggregates to improve their performance.
Utilizing treated 3 types of aggregates, mortar cubes were casted, and results are then compared to cubes casted using conventional sand and brick aggregate without any coating. The compressive strength result of GGBS coated brick aggregates at 28 days compared with sand and BA shows 5.57 % and 29.17 % more respectively. Fly ash and cement-coated aggregated performed comparatively lesser results than GGBS coating. Similar results are observed for water absorption and GGBS aggregates as the findings underscore the potential of utilizing recycled materials in construction, contributing to resource conservation and environmental protection. This research advocates for a paradigm shift towards sustainable practices in the construction industry, emphasizing the importance of recycling and reusing materials to mitigate the adverse effects of CDW on the environment.

PRODUCTION, PHYSICOCHEMICAL AND THERMODYNAMIC CHARACTERIZATION OF BIOETHANOL DERIVED FROM CORK: A PROMISING VALORIZATION PATHWAY FOR A NON-FOOD LIGNOCELLULOSIC WASTE

2025-10-02T15:13:57+00:00

This study investigates the potential of cork biomass, an underutilized lignocellulosic residue, to produce second-generation bioethanol. The process involved biomass preparation, Thermochemical pretreatment, concentrated acid hydrolysis, and alcoholic fermentation to convert the carbohydrate fraction of cork into fermentable sugars. The resulting bioethanol, obtained through distillation, reached a purity of 30 % (v/v). Physicochemical and thermodynamic caracteristics of the produced bioethanol included measurements of density, viscosity, flash point, calorific value, and vapor pressure. Spectroscopic analyses (FT-IR and Raman) were also conducted to confirm ethanol composition and purity. Despite its moderate purity, the bioethanol exhibited properties in line with initial fermentation - stage fuels, confirming the feasibility of cork as a raw material for biofuel production. These findings demonstrate a promising valorization route for cork waste within the framework of circular bioeconomy and sustainable energy development.

HARDNESS AND TRIBOLOGICAL BEHAVIOR OF CRAB SHELL PARTICLES REINFORCED ALUMINUM 6063 COMPOSITES

2025-05-26T22:49:04+00:00

The hardness and tribological behaviour of crab shell particles (CSPs) reinforced aluminium 6063 (Al-Mg-Si alloy) composites produced by the double stir casting method were investigated. Adding CSPs caused a marked improvement in the hardness and fracture toughness of the CSP composites, reflecting enhanced fracture resistance. The wear resistance enhancement of 1.56 % was noticed in 20 wt. % CSP composite, and abrasive wear was confirmed as the main wear process for the composites. The CSP composites showed a slight reduction in the density; with very low porosity indicating satisfactory wettability for the aluminium matrix, thus making the produced composite a good candidate material for the area of engineering lightweight applications.

INVESTIGATION OF THE MECHANICAL PROPERTIES OF TOOL STEEL 45WCrV7 AFTER RADIAL-SHEAR ROLLING

2025-11-24T14:07:09+00:00

The work is devoted to the study of the mechanical properties of low carbon tool steel 45WGrV7 after its volume-modification by application of an intensive plastic deformation process. Radial-shear rolling is a proven method of intensive plastic deformation in engineering practice, which produces quality long products with improved structure and properties.

In the present work, rods with different final diameters, obtained by radial-shear rolling were investigated by carrying out three different degrees of relative deformation along the diameter of the rots - 30, 50 and 60%. On the basis of tensile and hardness tests, the influence of radial-shear rolling on the mechanical properties of the investigated steel - hardness, tensile strength, conditional yield strength and elongation after failure - was established. The comparative analysis shows that the strength properties after rolling increase by more than 2 times compared to those of the original steel, approaching the properties of expensive high-alloy, high-carbon steels. The findings are a prerequisite for continuing research in order to study and improve the operational properties of the studied steel.

EFFECT OF AUSTENITIZATION AND COOLING MEDIUM ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF 12 % MANGANESE STEEL

2025-08-22T08:14:30+00:00

This study evaluates the mechanical properties of high manganese steel used in manufacturing hammers and grinding jaws, which reduce rocks into small particles. Four austenitization heat treatments (1025°C, 1050°C, 1075°C, and 1100°C) were applied, followed by quenching in water and ice water. Samples were characterized for microstructural and structural properties, as well as phase identification, using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Microhardness measurements revealed an increase in hardness from 436 HV0.2 for samples quenched in water at 1025°C to 680 HV0.2 for samples quenched in ice water at 1050°C. Impact resistance testing showed a resilience increase from 20 J cm-2 for samples treated at 1075°C in water to 161.27 J cm-2 for those treated at 1050°C in ice water. Tribological testing indicated a wear rate reduction from 6.23.10-4 mg m-1 for samples quenched in water to 0.3.10-4 mg m-1 for samples quenched in ice water. XRD results revealed an austenite solid solution phase across all samples, with additional martensitic and Mn7C3 - type carbide phases in those quenched in ice water. SEM analysis confirmed that manganese steel, austenitized for 45 min and quenched in water, shows coarse-grain carbide aggregates within an austenitic matrix. In contrast, samples quenched in ice water exhibit a compact matrix with fine-grain Mn7C3 - type carbides and martensite, resulting in enhanced mechanical performance. The 12 % Mn steel, austenitized at 1050°C and quenched in ice water, demonstrated the optimal combination of impact resistance and wear resistance.

MODELING OF ROLLABILITY OF SURFACE DEFECTS DURING COLD ASYMMETRIC ROLLING

2025-10-10T12:32:15+00:00

This paper presents the results of finite element modeling of the rollability of the most common surface defects (scratch, puncture, pressure) during cold rolling under symmetrical and asymmetric conditions with an asymmetry coefficient from 1 to 16. A steel strip with a thickness of 3 mm was used as an initial blank. The three surface defects were created on the surface, all defects had a depth of 0.5 mm. It was revealed that complete closure of all the defects studied during symmetrical rolling occurred only when initial blank was compressed by 80% higher (0.9 mm) than the initial defects depth. When using asymmetric rolling, an additional compression of 20% (0.6 mm) and an asymmetry level of 8 were required. Thus, asymmetric rolling can be considered an effective way to eliminate surface defects of a cold-rolled strip while providing a significantly lower compression level compared to symmetrical rolling.

ELECTRON BEAM WELDING OF TITANIUM AND ALUMINUM ALLOYS WITH A VANADIUM FILLER

2025-08-25T07:53:10+00:00

This work demonstrates the influence of using a V filler as an intermediate layer between Ti₆Al₄V and Al6082T6
plates. The study focuses on the microstructure and some mechanical properties of the weld seams created by electron
beam welding. The microstructure of the specimens was examined by X-ray diffraction (XRD), scanning electron
microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses. The study measured microhardness
and tensile properties of the samples. A weld seam rich in titanium was formed. This resulted in the presence of
γ-TiAl (L10) and α₂-Ti₃Al (D019) intermetallic phases. Using the V interlayer improved the distribution of Ti-Al
intermetallic in the fusion zone. The microhardness of the samples did not change substantially with the addition of
a V interlayer. In the fusion zone, it was 537 ± 43 HV0.05. With a V layer, it was 548 ± 50 HV0.05. However, tensile
properties showed a slight increase. The sample without a filler had an ultimate tensile strength of 45 ± 6 MPa. With
a V filler, it increased to 71 ± 11 MPa. This work proves that using V as an interlayer between Ti64 and Al6082T6
alloys is feasible for improving the structure and some mechanical properties. However, future studies are needed
to optimize the V integration procedure.