Chemical Industry & Chemical Engineering Quarterly
The Chemical Industry & Chemical Engineering Quarterly (CI&CEQ), as an international peer-reviewed research journal, invites contributions of original and novel fundamental research related to chemical industry and chemical engineering and connected areas. Papers describing novel theory and its application to practice as well as those reporting experimental work, which is soundly interpreted, are welcome. Articles published in this Journal are indexed in InCitesTMJournal Citation ReportsR - Clarivate and SCOPUS. The full search of the Journal is available through DOAJ. Need a Username/Password? P lease Register. Already have a Username/Password for CICEQ? GO TO LOGIN! Manuscript Submission Starting from June 2023 Processing Fee is 200 EUR +20 % VAT Editor-in-Chief Vlada Veljković Faculty of Technology, University of Niš, Bulevar oslobođenja 124, 16000 Leskovac, Serbia Associate Editors Srđan Pejanović Department of Chemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Serbia Dunja Sokolović Faculty of Technical Sceinces, University of Novi Sad, Serbia Ivona Radović Faculty of Technology and Metallurgy, University of Belgrade, Serbia Online ISSN 2217-7434 Print ISSN 1451-9372 This is an open access journal, which means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles in this journal without asking priorpermission from the publisher or the author.
Association of the Chemical Engineers of Serbia
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ENHANCING pH CONTROL IN A BIOREACTOR THROUGH EXPERIMENTAL SYSTEM IDENTIFICATION AND DYNAMIC ANALYSIS
The acidic by-products produced during fermentation can cause a drop in pH, which in turn affects the microorganisms' growth and the product's formation. In order to keep pH at the desired level, process control becomes necessary. The aim of this study is to develop a predictive model for pH behavior during the fermentation of Clostridium acetobutylicum through dynamic analysis and system identification. The First Order Plus Dead Time (FOPDT) model and the second-order Autoregressive Moving Average with Exogenous (ARMAX) model were the two approaches that were compared. While the FOPDT model was used to derive the PID controller parameters through transient analysis, the Smith and linear regression methods, the ARMAX model—identified with the Recursive Least Squares (RLS) method—was chosen for its better accuracy in capturing input-output dynamics. PID tuning was done with the Cohen-Coon method. The simulation results showed that setpoint tracking was successfully done, and the ARMAX model provided a more accurate representation of the system. The optimized PID controller recorded the minimum Integral of Squared Error (ISE) value of 50.82. This study points out effective modeling and control strategies for the production of stable pH during fermentation, thus providing very useful knowledge for other bioprocesses that require precise control.
Copyright (c) 2025 Zeynep Yilmazer Hitit, Gamze Demirtas, Bulent Akay https://creativecommons.org/licenses/by-nc-nd/4.0
TECHNO-ECONOMIC AND ENVIRONMENTAL ASSESSMENT OF ETHYL ESTER BIODIESEL PRODUCTION
Biodiesel is a key fuel for a zero-carbon future. Enzymatic synthesis using renewable materials can make it even more environmentally friendly. However, high enzyme costs and limited reuse hinder its economic feasibility. This study assessed the techno-economic and environmental performance of different processes for ethyl ester biodiesel production. The scenarios evaluated include: transesterification of soybean degummed oil using free and immobilized Eversa Transform 2.0, chemical alkaline catalysis of soybean oil, and transesterification of waste oil using ET. The main metrics were net present value and global warming potential. Results showed that the free enzyme outperformed the immobilized enzyme economically. However, chemical catalysis had an NPV nearly double that of the best free enzyme option. Sensitivity analysis revealed that enzyme cost and reuse rate were critical to net present value. Transesterification of waste oil with enzyme reuse had the lowest GWP (4.21 g CO2eq/MJ), making it the most environmentally favorable scenario. While life cycle assessment indicated lower global warming potential for enzymatic catalysis, further study is needed on emissions from enzymes. Depending on the enzyme and reuse rate, chemical catalysis might result in lower overall emissions. Integration with the biorefinery makes large-scale enzymatic biodiesel production economically viable and with low CO2eq emissions.
Copyright (c) 2025 Ediane S. Alves, Simone C. Miyoshi, Andrew M. Elias, Letícia P. Miranda, Paulo W. Tardioli, Roberto C. Giordano, Felipe F. Furlan https://creativecommons.org/licenses/by-nc-nd/4.0
ADVANCED pH NEUTRALIZATION CONTROL USING MODEL REFERENCE ADAPTIVE CONTROL (MRAC) WITH MIT RULE
This study presents the design and implementation of a Model Reference Adaptive Controller (MRAC) using the Massachusetts Institute of Technology (MIT) rule for a pH neutralization process in a continuous reactor. The inherent nonlinearity of acid-base reactions makes conventional Proportional–Integral–Derivative (PID) control insufficient in handling rapid pH variations. To address this, an adaptive control strategy was proposed, allowing the system to dynamically adjust control parameters based on real-time deviations from the reference model. The adaptation gain (γ) played a critical role in system stability and performance, with simulations and experimental results confirming that γ = 0.025 yielded optimal response characteristics. Higher adaptation gains accelerated convergence but introduced oscillations, while lower values slowed the response. MATLAB/Simulink simulations and real-time experimental validation demonstrated that MRAC effectively stabilized the system, achieving faster settling time and improved tracking performance compared to PID control. The findings suggest that MRAC with the MIT rule is a viable alternative for complex nonlinear processes, offering improved robustness against disturbances and set-point variations. Further enhancements, including the Normalized MIT rule and polynomial modeling, could further refine the controller’s effectiveness in industrial applications.
Copyright (c) 2025 Zeynep Yilmazer Hitit https://creativecommons.org/licenses/by-nc-nd/4.0
ADVISORY-BASED PRODUCT CONFIGURATOR USED IN CHILLER CONFIGURATION AND EVALUATION
This article presents the architecture and functional principle of an advisory-based product configurator. The program is used to create new and modify similar product configurations and is intended for users without in-depth expertise in technical fields. Due to its architecture, the configurator is designed to utilise the knowledge stored in the knowledge database. The selection is based on a combination of fuzzy inference rules and mapping techniques. Knowledge regarding the product is captured by using component-based matrices. The possibility of adding new knowledge and new rules is also provided. All this enables the configurator to link customer requirements and offers the possibility of selecting one or more products. In addition, it evaluates possible product variants based on the parameters specified by the user. The graphical representation of the results obtained includes the product technical documentation as well as a matrix representation of all the selected components and modules. The functional principle and evaluation of the product selection are demonstrated using a case study of a chiller for installation in an industrial plant. During the selection and evaluation of the chiller, better system performance is achieved with a chiller that has a water-based condenser.
Copyright (c) 2025 Krešimir Osman, Mato Perić, Dragi Stamenković, Mihailo Lazarević https://creativecommons.org/licenses/by-nc-nd/4.0
INFRARED DRYING OF CARROT SLICES: EFFECT OF POWER LEVELS ON KINETICS AND ENERGY EFFICIENCY
The aim of this study is to optimize the drying conditions for yellow carrots by investigating the effects of varying infrared (IR) power levels on drying kinetics. Following drying tests at IR power levels of 38, 50, 62, 74, and 88 W, the initial moisture content of carrot slices (6.95 kg water/kg dry matter) was decreased to 0.11 kg water/kg dry matter. Drying times ranged from 300 minutes at 38 W to 110 minutes at 88 W, demonstrating an inverse relationship between IR power and drying duration. Higher IR power levels accelerated the drying rate by enhancing energy transfer, which promoted moisture removal efficiency. Effective diffusion coefficients, calculated as ranging from 7.73×10-10 to 2.21×10-9 m²/s for the power levels of 38 W to 88 W, indicate an increase in moisture migration with higher power. The process's energy requirements were reflected in the activation energy for moisture diffusion (1.967 kW/kg). The Midilli and Kucuk model offered the best fit for characterizing the drying behaviour, and statistical analysis validated the model's correctness. These findings provide valuable insights for optimizing IR drying conditions to enhance the efficiency and quality of yellow carrot drying processes.
Copyright (c) 2025 Mehmet Soydan, İbrahim Doyma https://creativecommons.org/licenses/by-nc-nd/4.0
CROSS-FLOW MICROFILTRATION OF TRADITIONAL KOMBUCHA BEVERAGE USING CERAMIC TUBULAR MEMBRANE
The traditional kombucha beverage is produced through the metabolic activity of the microorganisms present in the kombucha culture on sweetened black tea at room temperature. The aim of this study was to investigate the influence of cross-flow microfiltration on the quality of the produced beverage. The produced beverage was microfiltered to assess the effect of cross-flow microfiltration on its quality. The quality characteristics examined included pH, total acidity, total soluble solids, turbidity, organic acids, in vitro antioxidant potential, and vitamin C as an antioxidant compound. The operational parameters of the process were transmembrane pressure (0.2, 0.6, and 1 bar) and feed flow rate (30, 90, and 150 Lh-1). The maximum permeate flux was achieved at the highest feed flow rates and transmembrane pressures. Microfiltration maintained (pH, total acidity, total soluble solids, lactic, formic, and oxalic acid), improved (turbidity and acetic acid), but also declined (malonic acid, vitamin C, and antioxidant potential), the quality of the traditional beverage. After the microfiltration, turbidity was reduced by 7-9 times, and the content of acetic acid amounted to around 1.20 g/L. The lowering of acetic acid content indicated the inhibition of acid buildup. Values of the coefficient of retention for all of the examined quality parameters, except turbidity, suggested that the overall influence of microfiltration was moderate.
Copyright (c) 2025 Jasmina Vitas , Aleksandar Jokić , Nataša Lukić , Selena Dmitrović , Danica Piper , Radomir Malbaša https://creativecommons.org/licenses/by-nc-nd/4.0
PERFORMANCE OPTIMIZATION OF ECM PARAMETERS FOR PALLADIUM COATED TOOL ELECTRODE USING MULTI-CRITERIA DECISION ANALYSIS METHOD
Electrochemical machining is an important process for fabricating difficult-to-cut materials. It is a much more advantageous process for creating excellent surface quality on a wide range of conductive materials. In this research, the electrode (cathode) is coated with less resistive palladium material through a sputtering process, and sodium electrolyte is added with 10 gl-1 ascorbic acid to improve Local electrolysis and reduce the sludge generation. The process parameters, specifically electrolyte concentration, machining voltage, duty cycle, and frequency, were varied on machining rate and overcut using the L27 orthogonal array experimental plan. ÉLimination Et Choix Traduisant la REalité (ELECTRE) is employed to find a suitable solution. Based on the ELECTRE method, the best factor combination is 29 g L-1electrolyte concentration, 12 V, 70% duty cycle, and 80 Hz frequency. The analysis of variance shows that machining voltage and electrolyte concentration are the considerable factors, with contribution percentages of 43.93% and 23.34%, respectively. As per the mean effect plot, the optimal combination is 29 g L-1electrolyte concentration, 12 V, 90% duty cycle, and 80 Hz frequency.
Copyright (c) 2025 https://creativecommons.org/licenses/by-nc-nd/4.0
POTENTIAL OF ULTRASONIC IRRADIATION IN POLYURETHANE DEGRADATION IN DEEP EUTECTIC SOLVENTS
This study explores the degradation of polyurethane (PU) using deep eutectic solvents (DES) combined with ultrasonic irradiation, aiming to develop sustainable recycling techniques for PU waste. DES, formed from choline chloride and urea, possesses environmentally friendly properties such as low toxicity and high solubility, making it suitable for chemical recycling. Degradation experiments were conducted at elevated temperatures (130-150 °C), both with and without ultrasonic assistance. The technique of GPC is applied to determine the molecular weight of raw PU and the degradation product. The structures of DES, PU, and its degradation products were analysed using FTIR and NMR. The results indicate that the application of ultrasonics significantly enhances the degradation rate at approximately 5.20% from 58.51 ± 0.04% to 63.71 ± 0.03% at a constant temperature of 150 °C. This improvement is attributed to cavitation-induced effects, which facilitate polymer chain breakdown. Molecular transformations were confirmed through the presence of NH₃ groups resulting from the break of the PU structure to form o-toluidine, as identified by NMR. Reaction pathways were established through structural analysis of both raw PU and its degradation products. These findings demonstrate the potential of ultrasonic-assisted DES in advancing chemical recycling strategies for PU, addressing environmental concerns related to persistent PU waste, and promoting sustainable waste management practices.
Copyright (c) 2023 Amirah Nasuha Mohd Razib, Nik Muhammad Azhar Nik Daud, Mohd Al Hafiz Mohd Nawi, Banu Ramasamy, Mohd Sharizan Sharizan Md Sarip, Amirul Ridzuan Abu Bakar, Mohd Asraf Mohd Zainudin, Ahmad Hazim Abdul Aziz https://creativecommons.org/licenses/by-nc-nd/4.0
STUDY OF COMBUSTION AND PERFORMANCE IN A DIESEL ENGINE FUELED BY BIODIESEL-NANOPARTICLE BLENDS
This study examines the combustion and performance of avocado waste peel biodiesel (AWPB) combined with graphene oxide nanoplates (GONPs) as a substitute fuel for diesel engines. It also aims to assess the impact of engine combustion and performance while considering the feasibility of employing waste materials in fuel generation. The test fuels diesel, AWPB, AWPB+GONPs 50 ppm, and AWPB+GONPs 100 ppm were evaluated. The results showed that in-cylinder pressure in AWPB decreased by approximately 3.6% compared to diesel, while the heat release rate (HRR) increased notably in the AWPB+GONPs 100 ppm blend. Additionally, diesel exhibited higher ignition delay (ID) and combustion duration (CD) than all biodiesel blends. The addition of GONPs in AWPB led to a 5.98% increase in brake thermal efficiency (BTE) and a 30.12% reduction in brake-specific energy consumption (BSEC) compared to diesel. However, diesel still demonstrated higher engine torque, indicated mean effective pressure (IMEP), and air-fuel ratio (A/F ratio) relative to biodiesel fuels, whereas AWPB showed a higher exhaust gas temperature (EGT). These findings suggest that avocado peel biodiesel, when enhanced with GONPs, is a viable and cleaner alternative to conventional diesel, offering improved combustion efficiency and reduced energy consumption.
Copyright (c) 2023 Mohanrajhu Nathamuni, Premkumar Duraisamy, Rajakumar Muthusamy Palani, Padmavathi Kuppusamy Ramamoorthy https://creativecommons.org/licenses/by-nc-nd/4.0
DESIGN OF INDUSTRY-CENTRIC CONTROLLER FOR MIMO CSTH PROCESS WITH ENHANCED DISTURBANCE REJECTION
This paper focuses on designing an advanced control scheme tailored for large-scale industrial processes, where controllers must maintain effective performance despite significant disturbances and setpoint changes. The primary focus of the proposed RTD-A controller is on robust disturbance rejection. RTD-A possesses the benefits of both conventional PID and MPC control schemes. As model-based methods face challenges in addressing increasingly complex processes, data-driven techniques have gained popularity in industrial system monitoring due to their ability to handle unknown physical models. In this work, both the first-principle and transfer function models of the CSTH system are developed using real-time data and represented as a multi-input, multi-output (MIMO) system. PID, MPC, and RTD-A controllers are then applied to regulate the temperatures of the two tanks. The performance of these controllers is carefully examined using integral performance criteria and the time domain analysis to accurately assess their dynamic behavior and control precision. The results demonstrate that the RTD-A controller exhibits superior performance in mitigating disturbances. The RTD-A control strategy exhibits outstanding performance with near-zero overshoot (0% in servo and about 0.05% in regulatory responses) and stable settling times close to 430 - 440 seconds in both tanks. Although MPC and PID controllers offer quicker responses, their greater overshoot and longer settling times establish RTD-A as the preferred method for achieving reliable, precise, and safe control in industrial processes.
Copyright (c) 2023 Pream Anand Siva Shankaran, Manamalli Deivasikamani, Vasanthi Damodaran, Mythily Mani https://creativecommons.org/licenses/by-nc-nd/4.0
COMBUSTION, PERFORMANCE, AND EMISSION CHARACTERISTICS OF A CI ENGINE USING Borassus flabellifer BIODIESEL BLENDS
Borassus flabellifer methyl esters (BFMEs) have a few attractive characteristics that make them a potential rival to diesel and other alternative fuels. This study presents the first comprehensive analysis of its performance, combustion, and emission characteristics in a diesel engine. In addition to a high calorific value, a high cetane number, and the availability of oxygen, constituting 10% of its total weight, it is also readily available. Experimental testing of BFMEs was conducted on a single-cylinder compression ignition (CI) engine in this stage. BFMEs were blended with diesel at various concentrations (20%, 40%, 60%, 80% and 100%). Blends of BFMEs were experimentally examined for their combustion properties, emissions, and performance. The CI engine was set to steady-state operation so that it would reach the optimum temperature for the conditions in which it was operating. Initially, it was found that neat BFMEs had the lowest thermal efficiency, while BFME20, BFME40, BFME60, and BFME80 all had a higher brake thermal efficiency (BTE) than BFME100 at rated load conditions (by 5.1%, 2.8%, 2.0%, and 1.4%, respectively). Compared to other blends, BFME20 and BFME40 have better fuel efficiency. Fuel efficiency was improved by a reason-able amount, and BFME20's consumption was reduced by 5.1% compared to BFME100. Compared to diesel, hydrocarbons, CO, and smoke emissions from BFME20 were reduced by 9.9%, 5.8%, and 3.71%, respectively. These results underscore the potential of low-ratio BFME blends as cleaner and more efficient biodiesel alternatives, highlighting BFME’s practical applicability in existing diesel engines without major modifications.
Performance and emission characteristics
Copyright (c) 2023 Sakthi Rajan Chandramurthy, Silambarasan Ragunathan, Ramesh Kumar Ayyakkannu, Anbarasan Baluchamy https://creativecommons.org/licenses/by-nc-nd/4.0
APPLYING DENSITY FUNCTIONAL THEORY TO PREDICT THE REDUCTION POTENTIAL IN THE INDIGO DYEING PROCESS
This study employs density functional theory (DFT) to quantify the electron donor-acceptor properties and polarizability of organic iron(II) salts as reducing agents in indigo dyeing processes. The potential of some iron(II) salts to serve as environmentally friendly alternatives to the ecologically harmful sodium dithionite in the indigo dyeing process was investigated. A comparative analysis assessed the redox potential of reduced indigo and the color strength of dyed fabrics. Experimental results identified iron(II) gluconate as the most efficient, yielding superior color intensity. Theoretical calculations using B3LYP/LANL2DZ confirmed the superior electron-donating ability of iron(II) gluconate compared to the other iron(II) salts. The indigo reduction ability with the iron(II) salts was evaluated on the basis of complexation energies. The theoretical thermodynamic study reveals that the indigo-iron(II) gluconate complex is the most thermodynamically stable, requiring less energy input for its formation compared to the other complexes. Iron(II) salts-to-indigo electron donations in the complexes studied have been revealed by Mulliken charge analysis. These findings highlight the efficiency of DFT-based approaches in accurately predicting the reducing capacity of iron(II) salts and their suitability as eco-friendly alternatives in indigo dyeing applications.
Copyright (c) 2023 Maha Abdelileh, Manel Ben Ticha, Nizar Meksi, Hatem DhaouadI https://creativecommons.org/licenses/by-nc-nd/4.0
GLUTEN AND GLUTEN-FREE BISCUITS WITH FUNCTIONAL COMPONENTS: PHYSICOCHEMICAL, NUTRITIONAL AND ANTIOXIDANT PROPERTIES
This study aims to determine the effect of different compounds on the nutritional, antioxidant, microstructural, and color characteristics of biscuits classified as gluten and gluten-free. Namely, biscuits are enriched with dietary fibers, acacia fibers, spent coffee grounds, and anthocyanins. The addition of these functional components to biscuit matrix affected the physical properties of the biscuits; namely, the spread factor value of all biscuits ranged from 2.98 to 7.88, the content of total polyphenols increased, the highest polyphenol content was obtained in the gluten-free biscuits with added coffee grounds (77.98 mg), while in the biscuits with wheat flour has in the range of 44.62–128.63 mg. All gluten-free biscuits can be labeled as products with "rich in fiber" (6.32–7.68 g/100 g) and with a higher antioxidant content compared to biscuits without added ingredients. The total number of microorganisms in the tested cookies is below acceptable limits. The findings of this study show that the inclusion of raw nutritional components in the recipe of traditional gluten and gluten-free biscuits leads to an improvement in the nutritional value and other quality characteristics of the fortified food products.
Copyright (c) 2023 Marija Menkinoska, Tatjana Pavlova, Zhivka Goranova, Angelina Sredovska Bozhinov, Zlatin Zlatev, Hyrije Koraqi, Anka Trajkoska Petkoska https://creativecommons.org/licenses/by-nc-nd/4.0
COMPARATIVE ANALYSIS OF MORINGA OIL AND RUBBER SEED OIL BIODIESELS IN DIESEL ENGINES
Energy resources are diminishing, and environmental problems are becoming more prevalent. In this regard, biodiesel from moringa oil (MO) and rubber seed oil (RSO) promises to be an excellent alternative to diesel fuels, while also requiring far less modification from existing diesel engines. Performance metrics analysis reveals that biodiesel consumes a slightly higher amount of fuel at lower loads because of its relatively lower calorific value. At 4.4 kW, MO methyl ester blend (MO20) achieved a brake thermal efficiency of 30%, outperforming diesel (26%) and RSO methyl ester blend (RB20) achieved a brake thermal efficiency of 28%. MO20 reduced CO emissions by 60% compared to diesel and 55% compared to RB20. Furthermore, MO20 increased NOx emissions by 10% at higher brake power levels compared to RB20 and 20% for diesel. RB20 and MO20 biodiesel blends exhibit lower HC compared to diesel by 24% and 28% respectively. These reductions in carbon monoxide and hydrocarbon emissions make biodiesel blends, mostly from MO, cleaner and well sustainable compared to conventional diesel, with their environmental and performance benefits for diesel engine applications.
SPRAY DRYING OF PHOSPHATE-SOLUBILIZING BACTERIA FOR THE PRODUCTION OF NEW BIOFERTILIZERS
Phosphate-solubilizing bacteria represent a sustainable solution to cope with phosphorus unavailability in agricultural soil. However, the success of their application is highly dependent on multiple environmental factors, and a novel approach is needed for bioformulations. The present study aimed to evaluate the suitability of the spray drying method for encapsulation of phosphate-solubilizing bacteria Azotobacter chroococcum F14/2, Bacillus megaterium 11/3, and Pseudomonas putida P1. Three strains were characterized, grown under optimal conditions, and encapsulated as a whole medium-cell system using the spray drying method and maltodextrin as carrier material. The described procedure provided encapsulates with an average particle size below 5 μm, moisture content under 10%, and satisfactory powder properties. The cell viability of encapsulates (after storage) was in the following order: Bacillus megaterium 11/3 > Azotobacter chroococcum F14/2 > Pseudomonas putida P1. Additional protection during spray drying was most probably achieved by the presence of microbial exopolysaccharides, which opened the possibilities for further optimization of encapsulation procedures.
REMOVAL OF ISOPROPYL ALCOHOL FROM WASTEWATER USING MODIFIED BENTONITE BY Fe, Cu, AND Fe-Cu
Catalysts based on purified bentonite (Be) pillared with Fe3+ (BeFe), Cu2+ (BeCu), and Fe-Cu (BeFe/Cu) were synthesized from Algerian bentonite and used to treat isopropyl alcohol (IPA) by catalytic wet peroxide oxidation (CWPO) with H2O2 at 298 K. The BeFe showed higher activity than the BeFe/Cu one for IPA removal, although the second was more active for H2O2 decomposition. The reaction kinetics were examined with both catalysts using the pseudo-first-order reaction model. The mechanism of H2O2 decomposition was known through different values of apparent activation energy (Ea) were determined from the Arrhenius equation 46 kJ/mol for BeFe with abundant formation of •OH radicals and 67 kJ/mol for BeFe/Cu with mainly production of O2 which has a low oxidation capacity at 298 K.
Copyright (c) 2023 Zohra Mecabih https://creativecommons.org/licenses/by-nc-nd/4.0
ANALYZING THE EFFICACY AND EXHAUSTS OF PUNNAI BIODIESEL-ETHANOL BLENDS IN NANOCOATED CI ENGINES
This study experimentally investigates the performance, emission, and combustion characteristics of a nano-coated compression ignition (CI) engine fueled by Punnai biodiesel blends with varying proportions of ethanol. The nano-coating was applied to the engine's cylinder liner and piston crown to enhance heat transfer and reduce friction. The biodiesel blends were prepared by mixing Punnai oil with diesel fuel in various ratios (B20, and B30). Ethanol was added to each blend at 5% and 15% concentrations. This research desires to improve the operational efficiency of an engine which runs on a diesel, through the utilisation of a piston coated with a thermal barrier, specifically tailored for punnai methyl ester blends. Thermal barrier coatings widely prioritise zirconia due to its exceptional thermal insulation properties. B20E15 has a brake thermal efficiency that exceeds that of diesel by around 3%. Similarly, B20E05 and B20E15 demonstrate fuel consumption reductions of approximately 3.8% and 16.3%, respectively. On average, the B20 blends exhibited a reduction in CO and HC emissions are 5% and 9%. A comparative analysis clearly demonstrated that nanocoated CI engines enhance performance and diminish emissions without any major modifications.
THE IMPACT OF HEAT STORAGE MATERIAL INTEGRATION IN AN EVACUATED TUBE COLLECTOR
This experimental research assessed the impacts of sensible and latent heat materials such as SAE 20W/40 (used engine oil), candelilla wax (CLW) and rice bran wax (RBW) in an evacuated tube solar air heater. Four distinct arrangements were studied: one without a thermal energy storage material (TESM), one with a sensible heat material (SHM), and two with latent heat materials (LHM), to enable comparative analysis. The maximum outlet temperature of air for ETC filled with engine oil was 108°C, for CLW 115°C and for RBW 133°C – all measured at 13:00 pm. However, without filling the TESM in the ETC, the outlet temperature was only 70 °C. The maximum temperature difference of air in the RBW material-filled ETSAH system was 94°C, whereas without TESM, the temperature was only 31°C at 13:00. The maximum efficiency of the ETSAH system was achieved when using RBW as a PCM rather than both CLW and used engine oil-filled TESM. Moreover, the efficiency of the system increases around 1.7 - 1.8 times when the velocity of air increases from 1.5 to 2.5 m/s.
Copyright (c) 2023 Rajasekar Chockkalingam, Rameshkumar Ramasamy, Barathiraja Rajendran https://creativecommons.org/licenses/by-nc-nd/4.0
INVESTIGATING THE ACIDITY EFFECT OF NIOBIA AS CATALYTIC SUPPORT FOR FURFURAL CONVERSION
As niobia (Nb2O5) is an accessible acid support in Brazil, the objective of this work was to evaluate the effect of acidity in Ni/Nb2O5 catalysts for the hydrogenation of furfural in liquid phase. Catalysts with 5, 10 and 15 wt% Ni content were prepared by wet impregnation, activated under H2 flow, and tested in furfural hydrogenation at 150°C and 5 MPa of H2. N2 physisorption results suggest pore blocking on the support as the amount of Ni increased. The larger crystallites identified in XRD for 15% Ni/Nb2O5 probably favored pore blocking, and the atomic composition in EDS versus XPS indicates a lower metallic dispersion for this solid. TPR and XPS results suggest all Ni catalysts are primarily constituted of reduced Ni species, while TPD-NH3 confirms that the acidity of the support was passed on to the catalysts. The 15 wt% Ni solid led to a slight decrease in activity, which can be related to its lower dispersion. Catalysts proved to be promising in terms of selectivity to furfuryl alcohol, which remained between 60 and 80% throughout the reaction. Also, acid sites-derived product difurfuryl ether was produced with all catalysts, and can be an interesting addition to the biorefineries portfolio.
Copyright (c) 2023 Mayra Martinelli Costa , Eduarda Caroline Duarte Amatte Coelho , Silvia Fernanda Moya , Raphael Soeiro Suppino https://creativecommons.org/licenses/by-nc-nd/4.0
GRAPE POMACE EXTRACT AS A COLORANT FOR TEXTILE PRINTING APPLICATIONS
The growing need to reduce the negative impact on the environment and human health, as well as to meet the growing demand for eco-friendly textiles, has led to the development of environmentally friendly printing techniques and the use of natural dyes in the textile industry. Grape pomace is important waste material in winemaking, and has been extensively studied for its potential as a source of compounds with biological properties, especially anthocyanins, pigments responsible for the red, purple, and blue colors in grapes. The aim of this paper was to examine the potential use of natural dye extracted from grape pomace of domestic cultivar crna Mirisavka (GPCM) in preparation of printing paste with alginate, citric acid, and tannic acid for printing on cotton fabric. Special focus was placed to achieve process color magenta, by adjusting the pH value of the extract obtained. The natural dye from GPCM was extracted using maceration with 80% methanol, followed by sonication to enhance the yield of bioactive compounds. GPCM extract demonstrated significant antioxidant activity measured by FRAP, DPPH, and ABTS+ tests, and moderate antibacterial activity against Staphylococcus aureus and Escherichia coli. The pH-dependent stability of anthocyanins in GPCM extract was examined, demonstrating a magenta tone at acidic pH (pH 2-4) and color degradation at higher pH values. Cotton fabric printed with two different concentrations of GPCM extract (100 mg/L and 50 mg/L) showed good antioxidant and antibacterial activity. Based on the obtained results, it can be concluded that GPCM extract can be an environmentally friendly solution for the development of antibacterial and antioxidant textiles, with potential application in the production of protective clothing in healthcare institutions, as well as for the production of decorative home textiles, for the production of children's toys and textiles for packaging.
Copyright (c) 2023 Branka Ružičić, Dragana Grujić, Aleksandar Savić, Ljiljana Topalić-Trivunović, Ana Velemir, Blanka Škipina, Sandra Dedijer, Miljana Prica https://creativecommons.org/licenses/by-nc-nd/4.0
INVOLVEMENT OF AMINOALKYLATED MERRIFIELD RESINS RETRACTED BY BIS(CHLORODIETHYL) ETHER IN METAL EXTRACTION
Merrifield resin, a cross-linked polystyrene resin with chloromethyl functional groups, is an extremely resilient material resistant to water and environmental degradation. Our objective is to develop novel substituted polymers with functional groups capable of chelating heavy metals for depollution applications. Cross-linked polymer networks, which are predominantly insoluble and adaptable to diverse chemical environments, are invaluable for pollution management. A key area of environmental significance is the selective retention of organic contaminants for purifying polluted water sources. This work focuses on creating new chelating polymeric sorbents for metal extraction by grafting ethylenediamine (EDA) and triethylenetetramine (TETA) onto Merrifield resin, resulting in two polymers: MR-EDA and MR-TETA. These modified polymers are further reticulated with bis(chlorodiethyl) ether to produce two novel reticulated polymers, MR-TETA-BCEE and MR-EDA-BCEE.To characterize the polymers, differential thermal analysis (DTA) and infrared (IR) spectroscopy are employed. The resins are subsequently tested for their ability to extract lead (Pb²⁺) and lithium (Li⁺) ions from aqueous solutions using the solid-phase extraction (SPE) method. Conductivity and atomic absorption spectrometry (AAS) analyses demonstrate high extraction efficiencies, ranging from 50% to 85% for both Pb²⁺ and Li⁺ ions. These results demonstrate the potential of MR-EDA-BCEE and MR-TETA-BCEE as effective polymeric sorbents for environmental remediation and heavy metal removal from water.
Copyright (c) 2023 Marwa Mrabet, Adnen Mabrouki, Fayçel Ammari https://creativecommons.org/licenses/by-nc-nd/4.0
DYE DEGRADATION USING PIPERAZINE ENCAPSULATED BIOSYNTHESIZED IRON NANOPARTICLES
This study investigates the breakdown of aniline yellow dye using biosynthesized iron nanoparticles that uses extract from Eryngium billardieri. Piperazine encapsulation in a chlorinated environment increased degradation efficiency, reaching up to 92% in the dark and 96% under photocatalytic conditions. Ultraviolet-visible spectroscopy (331.24 nm, 243.19 nm), Fourier Transform Infrared Spectroscopy (Fe–O at 539 cm⁻¹, C–N at 1231 cm⁻¹), X-ray Diffraction analysis (peaks at 26.31° to 76.84°, indicating FCC structure), and Energy Dispersive Spectroscopy (Fe and Cl presence) were used to characterize the nanoparticles. The N-functionalities produced from piperazine and Fe2+ (712 eV) were validated by X-ray Photoelectron Spectroscopy. Spherical, evenly distributed particles (10–30 nm) with core-shell morphology were seen by Field Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy. After encapsulation, Photoluminescence analysis showed less electron-hole recombination. Mesoporosity (type IV isotherms) was revealed by Brunauer-Emmett-Teller analysis, and the piperazine coating reduced surface area. Superparamagnetic behaviour with a blocking temperature close to 35K was found via magnetic measurements. High stability, catalytic efficiency, and potential for environmental remediation were all displayed by the encapsulated iron nanoparticles.
Copyright (c) 2023 Sathiya Selvaraj, Durairaj Sankaran, Ilangkumaran Mani https://creativecommons.org/licenses/by-nc-nd/4.0
POTENTIAL APPLICATION AS A BIO-COAGULANT FOR Moringa oleifera SEEDS
This study focused on producing a natural bio-coagulant from moringa seeds. Moringa seed extract is a natural coagulant for the treatment of water containing suspended solids and colloids and is obtained through grinding, oil extraction, protein extraction from the solids using 2 M NaCl solution, protein separation by centrifugation followed by filtration. This study investigated the production and use of bio-coagulants. Parameters investigated when producing the bio-coagulant include the effects of temperature on the removal of moisture content in the moringa seeds, the type of solvent on the oil yield, and varying the volume of n-hexane for oil extraction. Parameters investigated when using the bio-coagulant include the effect of dosage of bio-coagulant on pH and turbidity removal efficiency, and the performance of the bio-coagulant at low, medium, and high turbidity levels. The optimum temperature and time obtained by drying the moringa seeds was at 100 °C for 30 min and the highest oil yield obtained was 31% when using n-hexane as the solvent. Turbidity removal efficiency went up to 96.4 % when using 50 mg/L of the bio-coagulant at a pH of 6.1. High turbidity removal was achieved at low bio-coagulant dosages which was regarded as a breakthrough finding for this research.
Copyright (c) 2023 Amanda Zviuya, Joseph Govha, Placxedes Sigauke, amvurat@biust.ac.bw Mamvura , Gwiranai Danha https://creativecommons.org/licenses/by-nc-nd/4.0
NOVEL Achillea wilhelmsii C. KOCH NANOCOMPOSITE FABRICATION WITH EXTRAORDINARY PHYSICAL AND CHEMICAL PROPERTIES
In this paper, we utilized two techniques, steam extraction and Soxhlet extraction, to obtain the active components of Achillea wilhelmsii C.Koch. These active substances were then used to create composite nanofibers using an electrospinning machine. The morphology of the resulting nanocomposite was examined using a FESEM, and the results demonstrated that the electrospinning method and conditions were suitable. Additionally, we investigated and analyzed the anti-inflammatory efficacy of the nanocomposite produced through both methods. Furthermore, we compared and analyzed the strength, abrasion resistance, moisture content, and water supply of the samples we produced according to certain standards. Overall, the nanocomposite derived from Achillea wilhelmsii C.Koch exhibited promising properties that could be utilized in various industries.
Copyright (c) 2023 Mahsa Mohamadiyan https://creativecommons.org/licenses/by-nc-nd/4.0
List of Referees July 2024 to April 2025
EFFECT OF HOT AIR AND HOT AIR ASSISTED MICROWAVE DRYING ON DRYING KINETICS AND QUALITY OF RED AND WHITE PITAYA SLICES
In this study, mathematical modelling, drying kinetics, rehydration ratio (RR), shrinkage ratio (SR), color change (∆E), total phenolic content (TPC), antioxidant activity (AA) and microstructural examination of red and white pitaya fruits dried by hot air drying (HAD) and hot air assisted microwave drying (HA-MWD) methods were conducted. In the HAD and HA-MWD methods, the effective diffusion coefficient (Deff) increased as the drying time shortened. While the Page model provides the best fit to HA-MWD curves, HAD curves are also appropriately defined by the Parabolic Model. The RR value was found to be higher in the HA-MWD method. TPC values of fresh red and white pitaya fruits were calculated as 389.71±0.80 and 310.11±0.42 mg GAE 100 g-1 DM, respectively. The highest TPC value in HA drying was determined as 251.35±0.35 mg GAE 100 g-1 DM at 70 °C. In the HA-MWD method, TPC and AA decreased due to the increase in microwave power. In SEM monitoring, it was observed that crack and pore sizes increased with the temperature increase in HAD for both fruit types. The increase in microwave power caused more damage to the structure in the HA-MWD method.
Copyright (c) 2023 Pınar Şengün, Çetin Kadakal https://creativecommons.org/licenses/by-nc-nd/4.0
SLOT MILLING OF AA7075 REINFORCED WITH NANO SILICON CARBIDE PARTICLES – AN EXPERIMENTAL AND FINITE ELEMENT APPROACH
In the current trend, industries prefer to optimise machining processes using finite element-based machining simulation techniques. Aluminium alloy 7075 (AA7075) strengthened with nano Silicon Carbide particles (nSiCp) is utilized by industries as they exhibit good physical and mechanical properties. Slot milling is the essential machining operation to convert the component to the designed shape and size. However, excellent knowledge is required in selecting the appropriate machining parameters such as cutting velocity, feed and cutting tool material to ensure the quality of the components milled. In this research work, slot milling operation is carried out in the sample plates of AA7075 fortified with nSiCp content to 1.5 % of the weight. A 3D Finite Element Model (3D FEM) is developed using ABAQUS software for simulating slot milling operations to understand the influence of machining parameters on cutting forces, chip formation and chip morphology. The cutting force signals predicted by 3D FEM correlates 85 to 90 % with experimental data. The maximum shear stress of 175 MPa and Von Mises stress of 459 MPa were observed at the tool-workpiece interface. This validated 3D FEM facilitate to visualize and investigate the milling process and assists in selecting appropriate machining parameter settings. The effects of cutting velocity and feed on cutting forces, chip characteristics, stress and chip formation are reported.
Copyright (c) 2025 Prakash Chakrapani, Prakash Jayaraman https://creativecommons.org/licenses/by-nc-nd/4.0
SYNTHESIS AND CHARACTERIZATION OF ACTIVATED CARBON PRODUCED FROM HAZELNUT PEELS BY CHEMICAL ACTIVATION
Activated carbon was prepared in this research from hazelnut (Corylus avellana) peels with some additives which included polymeric waste (polymethyl methacrylate PMMA) and the raw material was ground to facilitate handling and different amounts of sodium hydroxide were added to it and the ratio [Corylus avellana peels: NaOH] was as follows: 1:0.5 to 1:2.5. (Corylus avellana) peels were also treated with polymeric waste materials at ratios of 5 - 25 % and a basic ratio of 1:2 at a temperature of 550 °C as it is considered an environmental pollutant and then part of it was disposed of by preparing a material with great economic feasibility. Then the adsorption properties of the prepared samples (methylene dye), iodine number, density, humidity and yield were evaluated and compared with the British and Russian commercial models, and (SEM, FT-IR) techniques were used to characterize the prepared activated samples. The results showed that activated carbon samples prepared from hazelnut peels were characterized by high iodine number (894.521 mg/g), methylene blue dye adsorption capacity (98.425 mg/g) and the yield (14.973 %).. As for the samples prepared from hazelnut peels with PMMA an increase was observed in the iodine values (1015.021 mg/g ) and adsorption capacity for methylene blue dye reached (148.000 mg/gm ) and yield also increased. This indicates that the addition process was a positive step in improving the specifications and productivity of activated carbon. As for the density and ash, humidity values, they were within the permissible limits for all the prepared activated carbon samples, and thus they greatly exceeded the specifications of commercial carbon samples
Copyright (c) 2023 Semaa Ibraheem Khaleel https://creativecommons.org/licenses/by-nc-nd/4.0