Pub Date : 2025-12-17DOI: 10.1016/j.sajce.2025.12.011
Muhammad Irfan Qadir , Ali B.M. Ali , Hakim AL Garalleh , Usman Majeed , Faheem ul Islam , Ali Raza , Sami Ullah Khan , Nodira Nazarova , Manish Gupta , M. Waqas , M. Ijaz Khan
This communication aims to develop a fractional mathematical model for flow of generalized Brinkman fluid with utilization of nanoparticles over vertically heated plate. A suspension of titanium oxide and molybdenum disulfide with water ) base fluid is considered to evaluates the heat transfer enhancement. Thermal properties of nanoparticles is presented. The problem is entertained with amplification of slip features. After formulating the governing equation, a novel fractional scheme namely Prabhakar technique is implemented. The integration framework is facilitated with famous Laplace technique. Physical interpretation of results has been revealed with different values of parameters. It is observed that velocity profile reduces due to Brinkman fluid parameter. Interaction of velocity slip parameter leads to decrement of velocity profile. Moreover, change in nanoparticles volume fraction leads to enhancement of temperature profile.
{"title":"Heat transfer enhancement in fractional Brinkman nanofluids: Effects of thermal and nanoparticle geometry","authors":"Muhammad Irfan Qadir , Ali B.M. Ali , Hakim AL Garalleh , Usman Majeed , Faheem ul Islam , Ali Raza , Sami Ullah Khan , Nodira Nazarova , Manish Gupta , M. Waqas , M. Ijaz Khan","doi":"10.1016/j.sajce.2025.12.011","DOIUrl":"10.1016/j.sajce.2025.12.011","url":null,"abstract":"<div><div>This communication aims to develop a fractional mathematical model for flow of generalized Brinkman fluid with utilization of nanoparticles over vertically heated plate. A suspension of titanium oxide <span><math><mrow><mo>(</mo><mrow><mi>T</mi><mi>i</mi><msub><mi>O</mi><mn>2</mn></msub></mrow><mo>)</mo></mrow></math></span> and molybdenum disulfide <span><math><mrow><mo>(</mo><mrow><mi>M</mi><mi>o</mi><msub><mi>S</mi><mn>2</mn></msub></mrow><mo>)</mo></mrow></math></span> with water <span><math><mrow><mo>(</mo><msub><mi>H</mi><mn>2</mn></msub><mi>O</mi></mrow></math></span>) base fluid is considered to evaluates the heat transfer enhancement. Thermal properties of nanoparticles is presented. The problem is entertained with amplification of slip features. After formulating the governing equation, a novel fractional scheme namely Prabhakar technique is implemented. The integration framework is facilitated with famous Laplace technique. Physical interpretation of results has been revealed with different values of parameters. It is observed that velocity profile reduces due to Brinkman fluid parameter. Interaction of velocity slip parameter leads to decrement of velocity profile. Moreover, change in nanoparticles volume fraction leads to enhancement of temperature profile.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 493-500"},"PeriodicalIF":0.0,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phenolic compounds in industrial wastewater pose significant environmental and health risks due to their toxicity and persistence. This study develops MnO₂/γ-Al₂O₃ catalysts for catalytic ozonation and examines how HNO₃ surface modification and calcination temperature influence γ-Al₂O₃ properties and catalytic performance. The optimized catalyst (MA-25-700-4 %) achieved the highest phenol degradation efficiency (92.23 %) with the fastest reaction rate (k = 0.0450 min⁻¹), outperforming catalysts prepared from unmodified commercial γ-Al₂O₃. Enhanced surface area, mesoporosity, and well-dispersed MnOx species promoted efficient ozone activation through the Mn(IV)/Mn(III) redox cycle, facilitating •OH radical generation. The catalyst also demonstrated good reusability over three catalytic ozonation cycles, with only a moderate decrease in reaction rate (k, reduced by ∼31 % from cycle 1 to cycle 3), confirming structural stability and sustained catalytic activity. These findings highlight the importance of controlled support modification and optimized Mn loading in engineering high-performance MnO2/γ-Al2O3 catalysts for advanced treatment of phenolic wastewater.
{"title":"Development of MnO2/γ-Al2O3 catalysts for catalytic ozonation of phenolic wastewater","authors":"Made Ayu Saraswati , Wibawa Hendra Saputera , Edlyn Lafina , Dwiwahju Sasongko","doi":"10.1016/j.sajce.2025.12.009","DOIUrl":"10.1016/j.sajce.2025.12.009","url":null,"abstract":"<div><div>Phenolic compounds in industrial wastewater pose significant environmental and health risks due to their toxicity and persistence. This study develops MnO₂/γ-Al₂O₃ catalysts for catalytic ozonation and examines how HNO₃ surface modification and calcination temperature influence γ-Al₂O₃ properties and catalytic performance. The optimized catalyst (MA-25-700-4 %) achieved the highest phenol degradation efficiency (92.23 %) with the fastest reaction rate (k = 0.0450 min⁻¹), outperforming catalysts prepared from unmodified commercial γ-Al₂O₃. Enhanced surface area, mesoporosity, and well-dispersed MnOx species promoted efficient ozone activation through the Mn(IV)/Mn(III) redox cycle, facilitating •OH radical generation. The catalyst also demonstrated good reusability over three catalytic ozonation cycles, with only a moderate decrease in reaction rate (k, reduced by ∼31 % from cycle 1 to cycle 3), confirming structural stability and sustained catalytic activity. These findings highlight the importance of controlled support modification and optimized Mn loading in engineering high-performance MnO<sub>2</sub>/γ-Al<sub>2</sub>O<sub>3</sub> catalysts for advanced treatment of phenolic wastewater.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 417-427"},"PeriodicalIF":0.0,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mangosteen pericarp, a major agricultural by-product, is a rich source of xanthones, including α- and γ-mangostin, which possess significant anticancer and anti-inflammatory properties. This study details the continuous production process for these bioactive compounds, focusing on material and energy balance, performance parameters, and preliminary economic feasibility. The process includes material pretreatment, extraction, and separation using a three-zone simulated moving bed (TZ-SMB) system.
Extraction experiments were optimized to model the yield of α-mangostin based on temperature and solvent (acetonitrile) concentration. The optimal extraction conditions were found to be 40 °C and 65 % v/v acetonitrile, achieving a maximum yield of 70.49 mg/g of dried pericarp. For the separation process, models based on triangle theory were developed to determine the maximum feed flow rate for the TZ-SMB system while ensuring at least 98 % relative purity for both compounds.
A block flow diagram was used for material and energy balance calculations, performed in MATLAB. The wet mangosteen pericarp feed rate was varied to achieve the target xanthone concentrations required for the TZ-SMB design. At the optimal solvent recycle ratio of 90 %, the system demonstrated a daily production capacity of 477.65 mg for α-mangostin and 140.76 mg for γ-mangostin, with a favorable benefit-to-cost ratio. The economic analysis confirms the process's profitability, especially with solvent recovery. This work provides a foundational preliminary design, supporting strategic decision-making and laying the groundwork for more detailed process design using simulation software.
{"title":"Process design for the continuous production of α- and γ-mangostin from mangosteen pericarp with integrated solvent recovery","authors":"Preuk Tangpromphan , Amaraporn Kaewchada , Attasak Jaree","doi":"10.1016/j.sajce.2025.12.008","DOIUrl":"10.1016/j.sajce.2025.12.008","url":null,"abstract":"<div><div>Mangosteen pericarp, a major agricultural by-product, is a rich source of xanthones, including α- and γ-mangostin, which possess significant anticancer and anti-inflammatory properties. This study details the continuous production process for these bioactive compounds, focusing on material and energy balance, performance parameters, and preliminary economic feasibility. The process includes material pretreatment, extraction, and separation using a three-zone simulated moving bed (TZ-SMB) system.</div><div>Extraction experiments were optimized to model the yield of α-mangostin based on temperature and solvent (acetonitrile) concentration. The optimal extraction conditions were found to be 40 °C and 65 % v/v acetonitrile, achieving a maximum yield of 70.49 mg/g of dried pericarp. For the separation process, models based on triangle theory were developed to determine the maximum feed flow rate for the TZ-SMB system while ensuring at least 98 % relative purity for both compounds.</div><div>A block flow diagram was used for material and energy balance calculations, performed in MATLAB. The wet mangosteen pericarp feed rate was varied to achieve the target xanthone concentrations required for the TZ-SMB design. At the optimal solvent recycle ratio of 90 %, the system demonstrated a daily production capacity of 477.65 mg for α-mangostin and 140.76 mg for γ-mangostin, with a favorable benefit-to-cost ratio. The economic analysis confirms the process's profitability, especially with solvent recovery. This work provides a foundational preliminary design, supporting strategic decision-making and laying the groundwork for more detailed process design using simulation software.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 460-474"},"PeriodicalIF":0.0,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.sajce.2025.12.007
Ekhlas A. Salman , Nawar S. Rasheed , Shaymaa A. Ahmed , Hasan F. Makki
This study examines the influence of Ammonium Persulfate (APS) solutions at varying concentrations (0.1, 0.5, 1, and 2 mol/L) on the thermal performance of counterflow cooling towers. It focuses on their effects on outlet water temperature, air heat gain, humidity variation along the tower height, and overall thermal range. Experimental findings demonstrate that the APS solution markedly enhances cooling performance by expanding the cooling range by up to 25 %, lowering the approach temperature by as much as 3C, and boosting thermal efficiency. APS shows superior performance under higher inlet water temperatures and variable environmental conditions. At a concentration of 1 mol/L, particularly within the temperature range of 50–45C, the efficiency increases by 17.6 %, rising from 72.81 % to 85.69 %. The enhancement in heat transfer is attributed to three synergistic mechanisms: increased evaporation due to reduced surface tension, enhanced latent heat absorption through mild endothermic decomposition, and the strong agreement between a physics-based heat and mass transfer model and the experimental data. These results confirm the viability of APS as an efficient, practical, and scalable additive for optimizing cooling tower performance across a wide range of operating conditions.
{"title":"Enhancing cooling tower efficiency using ammonium persulfate (APS) as a thermal performance additive","authors":"Ekhlas A. Salman , Nawar S. Rasheed , Shaymaa A. Ahmed , Hasan F. Makki","doi":"10.1016/j.sajce.2025.12.007","DOIUrl":"10.1016/j.sajce.2025.12.007","url":null,"abstract":"<div><div>This study examines the influence of Ammonium Persulfate (APS) solutions at varying concentrations (0.1, 0.5, 1, and 2 mol/L) on the thermal performance of counterflow cooling towers. It focuses on their effects on outlet water temperature, air heat gain, humidity variation along the tower height, and overall thermal range. Experimental findings demonstrate that the APS solution markedly enhances cooling performance by expanding the cooling range by up to 25 %, lowering the approach temperature by as much as 3C, and boosting thermal efficiency. APS shows superior performance under higher inlet water temperatures and variable environmental conditions. At a concentration of 1 mol/L, particularly within the temperature range of 50–45C, the efficiency increases by 17.6 %, rising from 72.81 % to 85.69 %. The enhancement in heat transfer is attributed to three synergistic mechanisms: increased evaporation due to reduced surface tension, enhanced latent heat absorption through mild endothermic decomposition, and the strong agreement between a physics-based heat and mass transfer model and the experimental data. These results confirm the viability of APS as an efficient, practical, and scalable additive for optimizing cooling tower performance across a wide range of operating conditions.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 398-404"},"PeriodicalIF":0.0,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-07DOI: 10.1016/j.sajce.2025.12.006
Emad A.M. Abdelghani, Abdulwahab Aljuhani
Operating at high temperatures, highly exothermic catalytic reactors require high transfer rates and safer operating conditions to achieve high performance. Fixed beds, moving bed contractors, normal and even usual design assembly of circulating beds, cannot provide large areas suitable for extremely high heat transfer rates. This study presents a novel design of a circulating fluidized bed (CFB). The designed Narrow Tubes Circulating Fluidized Bed (NTCFB) was constructed and tested in cold-model experiments. The riser column of NTCFB consists of mainly two heat exchanges. A double concentric pipe heat exchanger in the bottom attached directly to the plenum and a shell-and -tube heat exchanger at the top that has a bundle of 69 narrow tubes with 6 mm inside diameter. The hydrodynamics behavior in the NTCFB was investigated, where experiments were carried out to examine the flow characteristics and hydrodynamic behavior of the NTCFB in terms of several operating parameters such as the pressure drop across the grid and the top shell-and-tube riser in the absence and the presence of bed particles. Very small pressure drops across the grid and top riser were noticed at high gas velocities as high as 8.0 m/s. Pressure drops were found to be <2.0 % of the atmospheric pressure for the two parts of the NTCFB. Besides, Gas-solid flow behavior was investigated in terms of solid circulation rates in the NTCFB. Fluidization runs smoothly without pressure fluctuations for large bed particles up to 2.5 kg loading, irrespective of gas velocity.
{"title":"Process design and performance analysis of a narrow-tubes circulating fluidized bed with a double-heat exchanger riser","authors":"Emad A.M. Abdelghani, Abdulwahab Aljuhani","doi":"10.1016/j.sajce.2025.12.006","DOIUrl":"10.1016/j.sajce.2025.12.006","url":null,"abstract":"<div><div>Operating at high temperatures, highly exothermic catalytic reactors require high transfer rates and safer operating conditions to achieve high performance. Fixed beds, moving bed contractors, normal and even usual design assembly of circulating beds, cannot provide large areas suitable for extremely high heat transfer rates. This study presents a novel design of a circulating fluidized bed (CFB). The designed Narrow Tubes Circulating Fluidized Bed (NTCFB) was constructed and tested in cold-model experiments. The riser column of NTCFB consists of mainly two heat exchanges. A double concentric pipe heat exchanger in the bottom attached directly to the plenum and a shell-and -tube heat exchanger at the top that has a bundle of 69 narrow tubes with 6 mm inside diameter. The hydrodynamics behavior in the NTCFB was investigated, where experiments were carried out to examine the flow characteristics and hydrodynamic behavior of the NTCFB in terms of several operating parameters such as the pressure drop across the grid and the top shell-and-tube riser in the absence and the presence of bed particles. Very small pressure drops across the grid and top riser were noticed at high gas velocities as high as 8.0 m/s. Pressure drops were found to be <2.0 % of the atmospheric pressure for the two parts of the NTCFB. Besides, Gas-solid flow behavior was investigated in terms of solid circulation rates in the NTCFB. Fluidization runs smoothly without pressure fluctuations for large bed particles up to 2.5 kg loading, irrespective of gas velocity.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 428-438"},"PeriodicalIF":0.0,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gas hydrate-based desalination (GHBD) is a promising technology for sustainable water treatment, yet its practical implementation is often hindered by the slow kinetics and complexity of optimizing multiple process parameters. This study develops a robust decision-making framework using multi-criteria decision analysis (MCDA) to identify optimal conditions specifically volume, pressure, and stirring speed that enhance water recovery (WR) and moles of gas consumed. Experimental data were evaluated through MCDA based ranking methods to assess parameter performance. The results indicate that for CO₂ hydrate formation, the optimal conditions, 500 mL, at 3.0 MPa, provided a highest rank of 93 and stirring speed of 450 rpm with a rank of 32, produced a WR of 50%. In contrast, for CO₂+C₃H₈ hydrate systems in treating produced water (PW), at 2.0 MPa yielded the best performance with a highest rank of 39 and a WR of ∼60%. Unlike previous GHBD studies that primarily focus on feasibility and experimental characterization, this work introduces the first systematic MCDA based optimization framework for GHBD and provides experimentally validated optimal operating conditions. These findings highlight the importance of precise parameter selection and confirm the effectiveness of MCDA in guiding decision making for GHBD. This work introduces the first MCDA based framework for systematically optimizing operating parameters in GHBD. It uniquely shows that MCDA can reliably identify optimal CO₂ and CO₂ + C₃H₈ hydrate conditions, WR, efficient scalable desalination strategies, supporting long term environmental sustainability. and scalability of GHBD.
{"title":"Experimental validation and multi-criteria decision optimization of parameters in gas hydrate-based desalination","authors":"Sirisha Nallakukkala , Abdulrab Abdulwahab Almashwali , Bhajan lal , Yaman Hamed , Jagadish Ram Deepak Nallakukkala","doi":"10.1016/j.sajce.2025.12.005","DOIUrl":"10.1016/j.sajce.2025.12.005","url":null,"abstract":"<div><div>Gas hydrate-based desalination (GHBD) is a promising technology for sustainable water treatment, yet its practical implementation is often hindered by the slow kinetics and complexity of optimizing multiple process parameters. This study develops a robust decision-making framework using multi-criteria decision analysis (MCDA) to identify optimal conditions specifically volume, pressure, and stirring speed that enhance water recovery (WR) and moles of gas consumed. Experimental data were evaluated through MCDA based ranking methods to assess parameter performance. The results indicate that for CO₂ hydrate formation, the optimal conditions, 500 mL, at 3.0 MPa, provided a highest rank of 93 and stirring speed of 450 rpm with a rank of 32, produced a WR of 50%. In contrast, for CO₂+<em>C</em>₃H₈ hydrate systems in treating produced water (PW), at 2.0 MPa yielded the best performance with a highest rank of 39 and a WR of ∼60%. Unlike previous GHBD studies that primarily focus on feasibility and experimental characterization, this work introduces the first systematic MCDA based optimization framework for GHBD and provides experimentally validated optimal operating conditions. These findings highlight the importance of precise parameter selection and confirm the effectiveness of MCDA in guiding decision making for GHBD. This work introduces the first MCDA based framework for systematically optimizing operating parameters in GHBD. It uniquely shows that MCDA can reliably identify optimal CO₂ and CO₂ + <em>C</em>₃H₈ hydrate conditions, WR, efficient scalable desalination strategies, supporting long term environmental sustainability. and scalability of GHBD.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 389-397"},"PeriodicalIF":0.0,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1016/j.sajce.2025.12.004
Pham Van Trong , Vinh Nguyen Duy , Hoang Dinh Long , Nguyen Minh Thang
This study presents a comprehensive experimental investigation into the effects of Maz-Nitro additives (Maz 100 for gasoline and Maz 200 for diesel) on engine performance, fuel consumption, emissions, and material compatibility under both laboratory and road test conditions in Viet Nam. The research utilized A92 gasoline with Maz-Nitro 100, composed of 65%-90% base Maz ingredients and 10%-35% OGA-72012 (a mixture of aromatic hydrocarbons and microelements), and 0.05% S diesel with Maz-Nitro 200, composed of 65%-90% original Maz ingredients and 10%-35% Di-tert Butyl Peroxide (improved ether oil). The test fuels were blended with Maz-Nitro according to standard procedures and evaluated using chassis dynamometers, constant volume sampling (CVS) systems, and real-world driving cycles. Parameters examined included brake power, fuel consumption, exhaust emissions (CO, HC, NOₓ, CO₂), lubricant degradation, and wear of key engine components. Results showed that Maz 100 significantly reduced CO (65.53%) and HC (27.22%) emissions and improved fuel economy by 9.8%, albeit with increased NOₓ and CO₂. Conversely, Maz 200 achieved simultaneous reductions in CO, HC, NOₓ, and CO₂ by 34.82%, 20.93%, 22.22%, and 6.93%, respectively, alongside an 8.2% reduction in fuel consumption. Additionally, the additives did not increase engine component wear, highlighting their potential for sustainable automotive applications by enhancing performance and reducing environmental impact.
{"title":"Experimental study on the effects of Maz Nitro additive on engine performance and emissions","authors":"Pham Van Trong , Vinh Nguyen Duy , Hoang Dinh Long , Nguyen Minh Thang","doi":"10.1016/j.sajce.2025.12.004","DOIUrl":"10.1016/j.sajce.2025.12.004","url":null,"abstract":"<div><div>This study presents a comprehensive experimental investigation into the effects of Maz-Nitro additives (Maz 100 for gasoline and Maz 200 for diesel) on engine performance, fuel consumption, emissions, and material compatibility under both laboratory and road test conditions in Viet Nam. The research utilized A92 gasoline with Maz-Nitro 100, composed of 65%-90% base Maz ingredients and 10%-35% OGA-72012 (a mixture of aromatic hydrocarbons and microelements), and 0.05% S diesel with Maz-Nitro 200, composed of 65%-90% original Maz ingredients and 10%-35% Di-tert Butyl Peroxide (improved ether oil). The test fuels were blended with Maz-Nitro according to standard procedures and evaluated using chassis dynamometers, constant volume sampling (CVS) systems, and real-world driving cycles. Parameters examined included brake power, fuel consumption, exhaust emissions (CO, HC, NOₓ, CO₂), lubricant degradation, and wear of key engine components. Results showed that Maz 100 significantly reduced CO (65.53%) and HC (27.22%) emissions and improved fuel economy by 9.8%, albeit with increased NOₓ and CO₂. Conversely, Maz 200 achieved simultaneous reductions in CO, HC, NOₓ, and CO₂ by 34.82%, 20.93%, 22.22%, and 6.93%, respectively, alongside an 8.2% reduction in fuel consumption. Additionally, the additives did not increase engine component wear, highlighting their potential for sustainable automotive applications by enhancing performance and reducing environmental impact.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 405-416"},"PeriodicalIF":0.0,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research employed Quercus infectoria gall (QIG) extract as a reducing agent to produce metal nanoparticles (MNPs: Ag and Cu) and unveiled the reaction composition - MNPs morphology relationship. MNPs were synthesized by varying the volume ratio of metal ion solutions to QIG extract (1:1, 2:1, 4:1, and 8:1). Maximum absorption at specific wavelengths (Ag: 406–415 nm, and Cu: 320–325 nm) indicated the optimum formation of the AgNPs 8:1, and CuNPs 2:1. AgNPs were elongated and ellipsoid-shaped, while CuNPs were elongated block-shaped. The average size of AgNPs and CuNPs was 108 nm and 197.6 nm, respectively. The difference in the morphology and particle size of MNPs could be correlated with the reducibility of the metal ions and the presence of reducing groups (-OH) in the QIG extract. Metal ions with higher reduction potentials (Ag) tend to form more spherical MNPs due to the rapid reduction and nucleation of the MNPs. The ions with lower reduction potential (Cu) require a longer reduction time. This provides sufficient time for crystal growth, resulting in elongated particle morphology. This work provides a facile and sustainable strategy for designing MNPs with different morphologies.
{"title":"Sustainable synthesis of Ag and Cu nanoparticles using Quercus infectoria gall extract: A morphological perspective","authors":"Oka Shinta Sekar Kirana , Zulfa Syaifana Muslih , Fatimah Nurus Shobah , Retno Purbowati , Ade Irma Rozafia , Afifah Rosyidah , Wahyu Prasetyo Utomo , Norazlianie Sazali , Djoko Hartanto","doi":"10.1016/j.sajce.2025.12.003","DOIUrl":"10.1016/j.sajce.2025.12.003","url":null,"abstract":"<div><div>This research employed <em>Quercus infectoria</em> gall (QIG) extract as a reducing agent to produce metal nanoparticles (MNPs: Ag and Cu) and unveiled the reaction composition - MNPs morphology relationship. MNPs were synthesized by varying the volume ratio of metal ion solutions to QIG extract (1:1, 2:1, 4:1, and 8:1). Maximum absorption at specific wavelengths (Ag: 406–415 nm, and Cu: 320–325 nm) indicated the optimum formation of the AgNPs 8:1, and CuNPs 2:1. AgNPs were elongated and ellipsoid-shaped, while CuNPs were elongated block-shaped. The average size of AgNPs and CuNPs was 108 nm and 197.6 nm, respectively. The difference in the morphology and particle size of MNPs could be correlated with the reducibility of the metal ions and the presence of reducing groups (-OH) in the QIG extract. Metal ions with higher reduction potentials (Ag) tend to form more spherical MNPs due to the rapid reduction and nucleation of the MNPs. The ions with lower reduction potential (Cu) require a longer reduction time. This provides sufficient time for crystal growth, resulting in elongated particle morphology. This work provides a facile and sustainable strategy for designing MNPs with different morphologies.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 380-388"},"PeriodicalIF":0.0,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.sajce.2025.12.001
Neha Rajpal , Esther Naidoo , Ebrahim Kadwa , Sinethemba Xabela , Martina Dlasková , Olga Šolcová , Karel Soukup , Milan Carsky , David Lokhat
In this study, novel TiO2 doped photocatalysts based on carbon foam derived from Typha capensis, a sustainable and naturally abundant biomass source, were prepared and evaluated for removal of an organic dye. The carbon foam was produced through a unique two-step process involving baking and carbonization, followed by chemical activation using either NaOH or HCl to improve its surface area, porosity, and surface chemistry. TiO2 was then immobilised onto the activated carbon foam using a sol-gel method to enhance photocatalytic activity. The materials were extensively characterised, with BET surface area analysis showing a significant increase after chemical activation. The base-activated foam demonstrated the highest surface area. Microscopic analysis revealed a porous foam structure and confirmed the even distribution of TiO2 particles on the carbon surface. X-ray diffraction analysis verified the presence of the anatase phase of TiO2, which is known for its superior photocatalytic activity. Photocatalytic tests showed that the acid-activated carbon foam doped with TiO2 exhibited the best performance, achieving a Rhodamine B degradation efficiency of approximately 19% under UV light. The superior activity is believed to stem from the improved surface chemistry introduced by acid activation, which aids TiO2 dispersion and interaction with the pollutant molecules. This study highlights the potential of the novel carbon foam as a sustainable, low-cost, and potentially effective photocatalyst support for water treatment.
{"title":"Novel carbon-based photocatalysts for degradation of micropollutants","authors":"Neha Rajpal , Esther Naidoo , Ebrahim Kadwa , Sinethemba Xabela , Martina Dlasková , Olga Šolcová , Karel Soukup , Milan Carsky , David Lokhat","doi":"10.1016/j.sajce.2025.12.001","DOIUrl":"10.1016/j.sajce.2025.12.001","url":null,"abstract":"<div><div>In this study, novel TiO<sub>2</sub> doped photocatalysts based on carbon foam derived from <em>Typha capensis</em>, a sustainable and naturally abundant biomass source, were prepared and evaluated for removal of an organic dye. The carbon foam was produced through a unique two-step process involving baking and carbonization, followed by chemical activation using either NaOH or HCl to improve its surface area, porosity, and surface chemistry. TiO<sub>2</sub> was then immobilised onto the activated carbon foam using a sol-gel method to enhance photocatalytic activity. The materials were extensively characterised, with BET surface area analysis showing a significant increase after chemical activation. The base-activated foam demonstrated the highest surface area. Microscopic analysis revealed a porous foam structure and confirmed the even distribution of TiO<sub>2</sub> particles on the carbon surface. X-ray diffraction analysis verified the presence of the anatase phase of TiO<sub>2</sub>, which is known for its superior photocatalytic activity. Photocatalytic tests showed that the acid-activated carbon foam doped with TiO<sub>2</sub> exhibited the best performance, achieving a Rhodamine B degradation efficiency of approximately 19% under UV light. The superior activity is believed to stem from the improved surface chemistry introduced by acid activation, which aids TiO<sub>2</sub> dispersion and interaction with the pollutant molecules. This study highlights the potential of the novel carbon foam as a sustainable, low-cost, and potentially effective photocatalyst support for water treatment.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 358-367"},"PeriodicalIF":0.0,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.sajce.2025.12.002
Eko Adi Prasetyanto , Untung Gunawan , Dion Notario , Enade Perdana Istyastono , Meyliana Lukman Djaya , Shakira Aprillia Tanudjaja , Atthar Luqman Ivansyah
Molecularly imprinted polymers (MIP) offer highly selective recognition toward target analytes, yet their performance critically depends on the strength and nature of template–monomer interactions in the pre-polymerization stage. This study aims to develop a novel, integrative host-guest interaction approach that combines theoretical and experimental methodologies to support a rational MIP design framework. The computational elucidates the molecular recognition mechanism between voriconazole and monomers relevant to MIP formation, providing a detailed description of the complex stability and selectivity governed by non-covalent interactions. The interaction between voriconazole and 2-hydroxyethyl methacrylate (HEMA) was stabilized predominantly by hydrogen bonding and van der Waals interactions using a combination of energy analysis and electron density descriptors, supported by favorable binding energy and orbital overlap characteristics. Further investigation of multi-monomer complexes revealed that a 1:7 template-to-monomer ratio yields the most stable configuration, indicating cooperative binding effects. Non-covalent interaction analyses provided a comprehensive visualization of the domains of interaction and electron density features responsible for imprint specificity. Laboratory investigation, including the association constant and Job plot methods, confirmed the interaction of voriconazole and HEMA complex with a Ka value of 660±3729 M−1 and 1:7 template-to-monomer ratio at equilibrium in chloroform. These findings enhance the understanding of how non-covalent interactions govern the establishment of high-fidelity recognition sites and demonstrate the potential of computational assessments for the rational design of MIP, with implications for subsequent laboratory synthesis of MIP-based sensors.
{"title":"Unraveling the molecular recognition mechanism of voriconazole and functional monomers in molecularly imprinted polymer design","authors":"Eko Adi Prasetyanto , Untung Gunawan , Dion Notario , Enade Perdana Istyastono , Meyliana Lukman Djaya , Shakira Aprillia Tanudjaja , Atthar Luqman Ivansyah","doi":"10.1016/j.sajce.2025.12.002","DOIUrl":"10.1016/j.sajce.2025.12.002","url":null,"abstract":"<div><div>Molecularly imprinted polymers (MIP) offer highly selective recognition toward target analytes, yet their performance critically depends on the strength and nature of template–monomer interactions in the pre-polymerization stage. This study aims to develop a novel, integrative host-guest interaction approach that combines theoretical and experimental methodologies to support a rational MIP design framework. The computational elucidates the molecular recognition mechanism between voriconazole and monomers relevant to MIP formation, providing a detailed description of the complex stability and selectivity governed by non-covalent interactions. The interaction between voriconazole and 2-hydroxyethyl methacrylate (HEMA) was stabilized predominantly by hydrogen bonding and van der Waals interactions using a combination of energy analysis and electron density descriptors, supported by favorable binding energy and orbital overlap characteristics. Further investigation of multi-monomer complexes revealed that a 1:7 template-to-monomer ratio yields the most stable configuration, indicating cooperative binding effects. Non-covalent interaction analyses provided a comprehensive visualization of the domains of interaction and electron density features responsible for imprint specificity. Laboratory investigation, including the association constant and Job plot methods, confirmed the interaction of voriconazole and HEMA complex with a Ka value of 660±3729 M−1 and 1:7 template-to-monomer ratio at equilibrium in chloroform. These findings enhance the understanding of how non-covalent interactions govern the establishment of high-fidelity recognition sites and demonstrate the potential of computational assessments for the rational design of MIP, with implications for subsequent laboratory synthesis of MIP-based sensors.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 339-357"},"PeriodicalIF":0.0,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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