Pub Date : 2026-01-01Epub Date: 2025-11-24DOI: 10.1016/j.sajce.2025.11.019
Juan Pablo Arteaga-Ramos , Gabriel Alexandre-Pio , Millos Julian Enrique Jinete-Torres , José Claúdio Caraschi , Gretta Larisa Aurora Arce-Ferrufino , Ivonete Ávila , Carlos Manuel Romero-Luna
Due to the increase in energy demand in recent years, renewable energy sources have gained greater prominence, with biomass considered as the fourth source of renewable energy. In Brazil, a biomass of great importance is the woodchips generated by the industrial production of eucalyptus. Eucalyptus woodchips are mainly used as fuel in several industries, however, like other biomasses, they have some disadvantages such as low calorific value and high humidity. These disadvantages can be minimized by the torrefaction process. The literature has presented several options, one of which is oxidative dry torrefaction. Within oxidative torrefaction, there is a form where the biomass is immersed in a bed of inert material, however this form of torrefaction is still under study. In this work, sand-assisted oxidative torrefaction of eucalyptus woodchips is studied, evaluating the temperature in the range of 200 – 300 °C, the high of the mineral layer in 3, 6, 12 cm, and two times of torrefaction 30 and 60 min. The torrefaction temperature range was varied, in addition, variables such as time and height of the sand bed will be evaluated. The results obtained indicate that the yield of torrefied biomass is inversely proportional to temperature and time. Furthermore, the height of the sand bed has an influence on the yield and properties of the torrefied biomass. Sand-assisted oxidative torrefaction improves high heating value, reduces moisture content, and increases grindability.
{"title":"Oxidative torrefaction of eucalyptus woodchips using a silica sand layer for bioenergy enhancement","authors":"Juan Pablo Arteaga-Ramos , Gabriel Alexandre-Pio , Millos Julian Enrique Jinete-Torres , José Claúdio Caraschi , Gretta Larisa Aurora Arce-Ferrufino , Ivonete Ávila , Carlos Manuel Romero-Luna","doi":"10.1016/j.sajce.2025.11.019","DOIUrl":"10.1016/j.sajce.2025.11.019","url":null,"abstract":"<div><div>Due to the increase in energy demand in recent years, renewable energy sources have gained greater prominence, with biomass considered as the fourth source of renewable energy. In Brazil, a biomass of great importance is the woodchips generated by the industrial production of eucalyptus. Eucalyptus woodchips are mainly used as fuel in several industries, however, like other biomasses, they have some disadvantages such as low calorific value and high humidity. These disadvantages can be minimized by the torrefaction process. The literature has presented several options, one of which is oxidative dry torrefaction. Within oxidative torrefaction, there is a form where the biomass is immersed in a bed of inert material, however this form of torrefaction is still under study. In this work, sand-assisted oxidative torrefaction of eucalyptus woodchips is studied, evaluating the temperature in the range of 200 – 300 °C, the high of the mineral layer in 3, 6, 12 cm, and two times of torrefaction 30 and 60 min. The torrefaction temperature range was varied, in addition, variables such as time and height of the sand bed will be evaluated. The results obtained indicate that the yield of torrefied biomass is inversely proportional to temperature and time. Furthermore, the height of the sand bed has an influence on the yield and properties of the torrefied biomass. Sand-assisted oxidative torrefaction improves high heating value, reduces moisture content, and increases grindability.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 316-324"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680947","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 : 2026-01-01Epub Date: 2025-11-19DOI: 10.1016/j.sajce.2025.11.013
Ida Bagus Wayan Gunam , I Gede Arya Sujana , I M. Mahaputra Wijaya , I Wayan Arnata , Yohanes Setiyo , I Wayan Wisma Pradnyana Putra
The continuous increase in global demand for fossil-based fuels has driven the need for sustainable and renewable energy alternatives such as bioethanol. Wild cassava (Manihot glaziovii Muell. Arg), a non-edible starch-rich crop with high cyanogenic content, represents a promising feedstock for bioethanol production without competing with food resources. This study aimed to enhance bioethanol production efficiency from wild cassava flour (WCF) through various co-culture fermentation strategies combining Aspergillus niger FNCC 6018, isolate R5I4, and isolate R5I3 under Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) conditions. The fermentation was conducted at 35°C and pH 5 for 7–8 days in a 250 mL bioreactor containing 33.33 g of WCF and 166.67 mL of distilled water, with agitation at 100 rpm. Among 17 treatment combinations, the co-culture of R5I4, A. niger FNCC 6018, and R5I3, added at the 96th hour, yielded the highest ethanol concentration (28.277 ± 0.228 g/L), efficiency (46.20 ± 0.37%), productivity (0.168 g/L/h), and yield coefficient (0.028 g/g). SEM and HPLC analyses confirmed efficient starch hydrolysis and glucose-to-ethanol conversion. Phylogenetic analysis identified R5I3 as closely related to Candida orthopsilosis (91 %) and R5I4 to Klebsiella variicola (83 %). These findings demonstrate that wild cassava flour is a viable substrate for efficient bioethanol production using co-culture SSF/SSCF systems. Future work should focus on scaling up fermentation, optimizing environmental parameters, and exploring the metabolic engineering of the microbial consortium to improve ethanol yield and process economics further.
{"title":"Experimentation of various co-culture fermentation strategies for better efficiency bioethanol production using wild cassava flour (Manihot glaziovii Muell. Arg) as substrate","authors":"Ida Bagus Wayan Gunam , I Gede Arya Sujana , I M. Mahaputra Wijaya , I Wayan Arnata , Yohanes Setiyo , I Wayan Wisma Pradnyana Putra","doi":"10.1016/j.sajce.2025.11.013","DOIUrl":"10.1016/j.sajce.2025.11.013","url":null,"abstract":"<div><div>The continuous increase in global demand for fossil-based fuels has driven the need for sustainable and renewable energy alternatives such as bioethanol. Wild cassava (<em>Manihot glaziovii</em> Muell. Arg), a non-edible starch-rich crop with high cyanogenic content, represents a promising feedstock for bioethanol production without competing with food resources. This study aimed to enhance bioethanol production efficiency from wild cassava flour (WCF) through various co-culture fermentation strategies combining <em>Aspergillus niger</em> FNCC 6018, isolate R5I4, and isolate R5I3 under Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) conditions. The fermentation was conducted at 35°C and pH 5 for 7–8 days in a 250 mL bioreactor containing 33.33 g of WCF and 166.67 mL of distilled water, with agitation at 100 rpm. Among 17 treatment combinations, the co-culture of R5I4, <em>A. niger</em> FNCC 6018, and R5I3, added at the 96th hour, yielded the highest ethanol concentration (28.277 ± 0.228 g/L), efficiency (46.20 ± 0.37%), productivity (0.168 g/L/h), and yield coefficient (0.028 g/g). SEM and HPLC analyses confirmed efficient starch hydrolysis and glucose-to-ethanol conversion. Phylogenetic analysis identified R5I3 as closely related to <em>Candida orthopsilosis</em> (91 %) and R5I4 to <em>Klebsiella variicola</em> (83 %). These findings demonstrate that wild cassava flour is a viable substrate for efficient bioethanol production using co-culture SSF/SSCF systems. Future work should focus on scaling up fermentation, optimizing environmental parameters, and exploring the metabolic engineering of the microbial consortium to improve ethanol yield and process economics further.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 271-284"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621202","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 study investigates the optimization of CO₂ adsorption using activated serpentine in a fixed-bed reactor, focusing on the effects of particle size (50 to 150 mesh), activation temperature (650 to 850 °C), activation duration (1.5 to 4.5 h), and CO₂ flow rate (0.1 to 1.0 SLPM). Characterization results indicate that thermal activation enhances surface area, pore structure, and adsorption efficiency. Experimental findings reveal that activation at 850 °C, with a 100 mesh particle size, achieves the highest adsorption efficiency, while the 150 mesh fraction exhibits the highest adsorption rate (0.71 mL/min g). An activation duration of 1.5 h provides an optimal balance between structural stability and reactivity, whereas a flow rate of 0.5 SLPM results in the highest adsorption efficiency (R² = 99.55 %). Breakthrough curve analysis confirms that smaller particle sizes and lower flow rates extend adsorption duration and enhance overall adsorption efficiency. Kinetic modeling using the Thomas, Yoon-Nelson, and Clark models demonstrates that the Clark and Yoon-Nelson models provide the most accurate predictions, with R² values reaching up to 99.55 % and lower Reduced Chi-Square values across various experimental conditions. The optimized adsorption conditions, including 850 °C activation, 100 mesh particle size, 1.5 h activation duration, and a 0.5 SLPM flow rate, achieve a balance between adsorption capacity and kinetics. These findings contribute to the advancement of serpentine-based adsorbents for carbon capture and storage (CCS) applications, supporting efforts to mitigate industrial CO₂ emissions.
{"title":"Enhanced CO₂ adsorption capacity using activated serpentine: A study of process variables and breakthrough curve analysis","authors":"Alvan Ade Reza , Mahidin Mahidin , Yunardi Yunardi , Asri Gani , Edi Munawar","doi":"10.1016/j.sajce.2025.10.003","DOIUrl":"10.1016/j.sajce.2025.10.003","url":null,"abstract":"<div><div>This study investigates the optimization of CO₂ adsorption using activated serpentine in a fixed-bed reactor, focusing on the effects of particle size (50 to 150 mesh), activation temperature (650 to 850 °C), activation duration (1.5 to 4.5 h), and CO₂ flow rate (0.1 to 1.0 SLPM). Characterization results indicate that thermal activation enhances surface area, pore structure, and adsorption efficiency. Experimental findings reveal that activation at 850 °C, with a 100 mesh particle size, achieves the highest adsorption efficiency, while the 150 mesh fraction exhibits the highest adsorption rate (0.71 mL/min g). An activation duration of 1.5 h provides an optimal balance between structural stability and reactivity, whereas a flow rate of 0.5 SLPM results in the highest adsorption efficiency (R² = 99.55 %). Breakthrough curve analysis confirms that smaller particle sizes and lower flow rates extend adsorption duration and enhance overall adsorption efficiency. Kinetic modeling using the Thomas, Yoon-Nelson, and Clark models demonstrates that the Clark and Yoon-Nelson models provide the most accurate predictions, with R² values reaching up to 99.55 % and lower Reduced Chi-Square values across various experimental conditions. The optimized adsorption conditions, including 850 °C activation, 100 mesh particle size, 1.5 h activation duration, and a 0.5 SLPM flow rate, achieve a balance between adsorption capacity and kinetics. These findings contribute to the advancement of serpentine-based adsorbents for carbon capture and storage (CCS) applications, supporting efforts to mitigate industrial CO₂ emissions.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 50-62"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145420017","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 : 2026-01-01Epub Date: 2025-11-21DOI: 10.1016/j.sajce.2025.11.017
Sujesh Sudarsan, Ramesh Vinayagam, Raja Selvaraj
This investigation introduces a comprehensive machine-learning (ML) scheme for accurately predicting the uptake of the cationic dye Malachite Green (MG) onto superparamagnetic activated carbon derived from Spathodea campanulata flowers. Batch adsorption experiments data covering a wide range of solution pH, sorbent dosage, initial dye concentration, contact time, and temperature were used to compare four predictive models: multiple linear regression (MLR), artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). Pearson correlation analysis revealed contact time as the dominant positive factor influencing adsorption capacity (Qe). Among MLR variants, the interaction-linear model achieved the best fit (R2 = 0.8901). SVM with a medium Gaussian kernel improved accuracy substantially (R2= 0.9577). ANN delivered similarly strong predictive power (overall R2 =0.9672) by learning complex multidimensional patterns. ANFIS emerged as the most robust and generalizable model, achieving R2 = 0.9683 with the lowest mean squared error (0.0098), root mean squared error (0.0992), and mean absolute error (0.0311). Sensitivity analysis of the optimized ANFIS confirmed the primacy of contact time (56.8 %), followed by initial concentration (33.2 %), dosage (3.6 %), temperature (3.3 %), and pH (3.1 %). This integrated experimental–computational approach offers a scalable, data-driven strategy for designing magnetically recoverable adsorbents and optimizing dye remediation in complex wastewater matrices.
{"title":"Advanced machine-learning frameworks for predicting malachite green adsorption onto superparamagnetic-activated carbon derived from Spathodea campanulata flowers","authors":"Sujesh Sudarsan, Ramesh Vinayagam, Raja Selvaraj","doi":"10.1016/j.sajce.2025.11.017","DOIUrl":"10.1016/j.sajce.2025.11.017","url":null,"abstract":"<div><div>This investigation introduces a comprehensive machine-learning (ML) scheme for accurately predicting the uptake of the cationic dye Malachite Green (MG) onto superparamagnetic activated carbon derived from <em>Spathodea campanulata</em> flowers. Batch adsorption experiments data covering a wide range of solution pH, sorbent dosage, initial dye concentration, contact time, and temperature were used to compare four predictive models: multiple linear regression (MLR), artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM). Pearson correlation analysis revealed contact time as the dominant positive factor influencing adsorption capacity (Q<sub>e</sub>). Among MLR variants, the interaction-linear model achieved the best fit (R<sup>2</sup> = 0.8901). SVM with a medium Gaussian kernel improved accuracy substantially (R<sup>2</sup>= 0.9577). ANN delivered similarly strong predictive power (overall R<sup>2</sup> =0.9672) by learning complex multidimensional patterns. ANFIS emerged as the most robust and generalizable model, achieving R<sup>2</sup> = 0.9683 with the lowest mean squared error (0.0098), root mean squared error (0.0992), and mean absolute error (0.0311). Sensitivity analysis of the optimized ANFIS confirmed the primacy of contact time (56.8 %), followed by initial concentration (33.2 %), dosage (3.6 %), temperature (3.3 %), and pH (3.1 %). This integrated experimental–computational approach offers a scalable, data-driven strategy for designing magnetically recoverable adsorbents and optimizing dye remediation in complex wastewater matrices.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 244-254"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621232","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":"2026-01-01","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}
The macroalga Sargassum siliquosum contains amino-cellulose bioactive compounds that act as stabilizing agents and growth controllers for metal precursor ions in the synthesis of Mg-Y/ZnO nanorods. This study aims to improve the multifunctional biomedical performance of ZnO (antibacterial, antioxidant, anti-inflammatory, and antidiabetic) through bimetal ion doping using Magnesium (Mg2+, 0.71 Å) and Yttrium (Y3+, 1.05 Å) at concentration ratios of 0.01–0.03 M within the ZnO lattice. Thermal analysis (TGA/DTA) shows that Mg-Y doping reduces the thermal stabilization temperature of ZnO from 800°C to 600°C. X-ray diffraction confirms the formation of a hexagonal wurtzite structure without secondary phases, supported by Rietveld refinement, FT-IR bonding profiles, and UV-Vis (Tauc plot) band gap narrowing to 3.01–3.10 eV. FE-SEM images reveal nanorod morphology of 25–35 µm, while EDX verifies Mg and Y incorporation. The doped samples exhibit strong antibacterial activity, with inhibition zones of ≥ 20 mm against Staphylococcus aureus and Pseudomonas aeruginosa. The 0.03 M Mg-Y/ZnO sample exhibits the highest biomedical performance, with significant antioxidant (IC₅₀ = 71.6 mg/L), anti-inflammatory (368 mg/L), and antidiabetic (420 mg/L) activities. These results indicate that Mg-Y bimetal doping enhances ZnO functionality and offers promising potential as a multifunctional biomedical material.
{"title":"Green synthesis of bimetal Mg-Y doped ZnO nanorods using extract of Sargassum siliquosum and their potential as biomedical materials","authors":"Yetria Rilda , Wilna Putri Akmalya , Upita Septiani , Syukri Syukri , Anthoni Agustien , Hilfi Pardi , Nofrijon Sofyan","doi":"10.1016/j.sajce.2025.11.003","DOIUrl":"10.1016/j.sajce.2025.11.003","url":null,"abstract":"<div><div>The macroalga Sargassum siliquosum contains amino-cellulose bioactive compounds that act as stabilizing agents and growth controllers for metal precursor ions in the synthesis of Mg-Y/ZnO nanorods. This study aims to improve the multifunctional biomedical performance of ZnO (antibacterial, antioxidant, anti-inflammatory, and antidiabetic) through bimetal ion doping using Magnesium (Mg<sup>2+</sup>, 0.71 Å) and Yttrium (Y<sup>3+</sup>, 1.05 Å) at concentration ratios of 0.01–0.03 M within the ZnO lattice. Thermal analysis (TGA/DTA) shows that Mg-Y doping reduces the thermal stabilization temperature of ZnO from 800°C to 600°C. X-ray diffraction confirms the formation of a hexagonal wurtzite structure without secondary phases, supported by Rietveld refinement, FT-IR bonding profiles, and UV-Vis (Tauc plot) band gap narrowing to 3.01–3.10 eV. FE-SEM images reveal nanorod morphology of 25–35 µm, while EDX verifies Mg and Y incorporation. The doped samples exhibit strong antibacterial activity, with inhibition zones of ≥ 20 mm against Staphylococcus aureus and Pseudomonas aeruginosa. The 0.03 M Mg-Y/ZnO sample exhibits the highest biomedical performance, with significant antioxidant (IC₅₀ = 71.6 mg/L), anti-inflammatory (368 mg/L), and antidiabetic (420 mg/L) activities. These results indicate that Mg-Y bimetal doping enhances ZnO functionality and offers promising potential as a multifunctional biomedical material.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 119-130"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517647","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 : 2026-01-01Epub Date: 2025-12-18DOI: 10.1016/j.sajce.2025.12.012
Salma Jahan, Rehena Nasrin
Compact energy systems need working fluids with exceptional heat transfer (HT) properties for effective thermal management. Though their behavior in complex microchannels is little studied, tetra-hybrid nanofluids of four nanoparticles show great potential. This research employs numerical analysis to investigate the thermo-hydraulic characteristics of a tetra-hybrid nanofluid comprising multi-walled carbon nanotubes (MWCNT), boron nitride (BN), nanodiamond (ND), and graphene (G) in a sinusoidal wavy crossflow microchannel heat exchanger (SWCFMCHE). The governing equations were solved using Galerkin’s weighted residual finite element method (FEM). Furthermore, an artificial neural network (ANN) model was developed to accurately predict key performance parameters such as Nusselt number (Nu), efficiency (ε), and performance index (η). The wavy microchannel heat exchanger’s heat transfer rate (HTR) was assessed by varying several important factors, such as the nanoparticle solid-volume fraction ( = 0.01–2 %), number of wave cycles (NWC = 0–3), inlet velocity ( = 0.0038–0.2479 m/s), and heat exchanger (HE) material (copper, aluminum, and stainless steel). For comparison, several heat transferring fluids, including water and water-based hybrid, ternary, and tetra-hybrid nanofluids, were also investigated. Results show that tetra-hybrid nanofluid offers the highest HTR among all tested fluids at equal concentration ratios, = 2 %, particle diameter (dp) = 1 nm, nanoparticles shape factor () = 16.1576, and NWC = 2. In case of tetra-hybrid nanofluid, the highest = 16.749 is achieved at m/s, showing enhancements of 19 %, 13 %, 9 %, and 4 % compared to all other heat transferring fluids. The highest efficiency (71.2 %) and performance index (601 × 10³) are observed for the tetra hybrid nanofluid at m/s. The ANN model accurately predicts thermo-hydraulic parameters. Overall, this integrated numerical and data-driven framework offers new insights into nanoparticle synergy and geometric enhancement, making a significant contribution to the design of efficient heat exchangers (HEs).
{"title":"Predictive ANN analysis of hydrothermal and entropy behavior of corrugated heat exchanger featuring tetra-hybrid nanofluid","authors":"Salma Jahan, Rehena Nasrin","doi":"10.1016/j.sajce.2025.12.012","DOIUrl":"10.1016/j.sajce.2025.12.012","url":null,"abstract":"<div><div>Compact energy systems need working fluids with exceptional heat transfer (HT) properties for effective thermal management. Though their behavior in complex microchannels is little studied, tetra-hybrid nanofluids of four nanoparticles show great potential. This research employs numerical analysis to investigate the thermo-hydraulic characteristics of a tetra-hybrid nanofluid comprising multi-walled carbon nanotubes (MWCNT), boron nitride (BN), nanodiamond (ND), and graphene (G) in a sinusoidal wavy crossflow microchannel heat exchanger (SWCFMCHE). The governing equations were solved using Galerkin’s weighted residual finite element method (FEM). Furthermore, an artificial neural network (ANN) model was developed to accurately predict key performance parameters such as Nusselt number (<em>Nu</em>), efficiency (ε), and performance index (<em>η</em>). The wavy microchannel heat exchanger’s heat transfer rate (HTR) was assessed by varying several important factors, such as the nanoparticle solid-volume fraction (<span><math><mi>ϕ</mi></math></span> = 0.01–2 %), number of wave cycles (NWC = 0–3), inlet velocity (<span><math><msub><mi>u</mi><mi>i</mi></msub></math></span> = 0.0038–0.2479 m/s), and heat exchanger (HE) material (copper, aluminum, and stainless steel). For comparison, several heat transferring fluids, including water and water-based hybrid, ternary, and tetra-hybrid nanofluids, were also investigated. Results show that tetra-hybrid nanofluid offers the highest HTR among all tested fluids at equal concentration ratios, <span><math><mi>ϕ</mi></math></span> = 2 %, particle diameter (<em>dp</em>) = 1 nm, nanoparticles shape factor (<span><math><mi>n</mi></math></span>) = 16.1576, and NWC = 2. In case of tetra-hybrid nanofluid, the highest <span><math><mrow><mi>N</mi><mi>u</mi></mrow></math></span> = 16.749 is achieved at <span><math><mrow><msub><mi>u</mi><mi>i</mi></msub><mo>=</mo><mn>0.2479</mn></mrow></math></span>m/s, showing enhancements of 19 %, 13 %, 9 %, and 4 % compared to all other heat transferring fluids. The highest efficiency (71.2 %) and performance index (601 × 10³) are observed for the tetra hybrid nanofluid at <span><math><mrow><msub><mi>u</mi><mi>i</mi></msub><mo>=</mo><mn>0.0038</mn></mrow></math></span> m/s. The ANN model accurately predicts thermo-hydraulic parameters. Overall, this integrated numerical and data-driven framework offers new insights into nanoparticle synergy and geometric enhancement, making a significant contribution to the design of efficient heat exchangers (HEs).</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 439-459"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839565","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}
In this work, we report the effect of temperature in the preparation of TiO2 nanoparticles with spherical and quasi-octahedral shapes and a modulated surface area ranging from 103 to 245 m² g-¹ using the peptization-hydrothermal method without porosity, size and shape controlling agents; varying the temperature to achieve particle sizes of 9 to 20 nm and porosities from 32 to 120 Å. It was observed that photovoltaic parameters were also modified. The TiO2 samples were characterized by XRD, BET, TEM, DRS, TGA, and I-V curves. The increase in synthesis temperature correlates with particle and pore size, as well as a reduction in surface area. However, when the synthesis temperature was 210 °C, the surface area decreased by 42 %. The TiO2 samples were used to prepare ethyl cellulose pastes for fabricating thin-film photoanodes in dye-sensitized solar cells (DSSCs). The photovoltaic results showed that the sample prepared at 180 °C exhibited the most suitable textural properties and crystalline orientation for DSSC applications.
{"title":"Synthesis of TiO2 nanoparticles with (001) preferential plane for photovoltaic performance in DSSC","authors":"Paulina Vargas-Rodriguez , Carolina Silva-Carrillo , Brenda Alcantar-Vazquez , Rosa-María Félix-Navarro , Rosalío Velarde-Barraza , Edgar-Alonso Reynoso-Soto","doi":"10.1016/j.sajce.2025.10.007","DOIUrl":"10.1016/j.sajce.2025.10.007","url":null,"abstract":"<div><div>In this work, we report the effect of temperature in the preparation of TiO<sub>2</sub> nanoparticles with spherical and quasi-octahedral shapes and a modulated surface area ranging from 103 to 245 m² g<sup>-</sup>¹ using the peptization-hydrothermal method without porosity, size and shape controlling agents; varying the temperature to achieve particle sizes of 9 to 20 nm and porosities from 32 to 120 Å. It was observed that photovoltaic parameters were also modified. The TiO<sub>2</sub> samples were characterized by XRD, BET, TEM, DRS, TGA, and I-V curves. The increase in synthesis temperature correlates with particle and pore size, as well as a reduction in surface area. However, when the synthesis temperature was 210 °C, the surface area decreased by 42 %. The TiO<sub>2</sub> samples were used to prepare ethyl cellulose pastes for fabricating thin-film photoanodes in dye-sensitized solar cells (DSSCs). The photovoltaic results showed that the sample prepared at 180 °C exhibited the most suitable textural properties and crystalline orientation for DSSC applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 72-82"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467802","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 : 2026-01-01Epub Date: 2025-10-03DOI: 10.1016/j.sajce.2025.10.001
Md.Rajibul Akanda, Md. Foysal Hasan, Md. Al-Amin
This study presents the eco-friendly approach for synthesizing zinc oxide nanoparticles (ZnO NPs) using Brunfelsia americana leaf extract as a novel bioreductant, serving dual roles as a reducing and stabilizing agent. The influence of solvent type, calcination conditions, and extract concentration on nanoparticle formation was systematically explored to optimize synthesis efficiency. A distinct color change and a UV–visible absorption peak near 360 nm confirmed the formation of ZnO NPs. Structural and morphological analyses using FTIR, XRD, SEM, and EDX revealed the presence of surface functional groups, a predominantly spherical shape, particle sizes ranging from 35 to 50 nm (average ∼45 nm), elemental composition, and a crystalline hexagonal wurtzite phase with a crystallite size of 36.09 nm and the specific surface area was calculated to be 29.63 m2/g (XRD / crystallite-based estimate). The prepared ZnO NPs were evaluated for their ability to adsorb malachite green (MG) dye from aqueous solutions. Optimal adsorption occurred under the conditions: pHZPC of 7.48, solution pH of 8.0, initial dye concentration of 30 mg/L, nanoparticle dosage of 0.3 g/L, contact time of 210 min and agitation speed of 300 rpm. Under these parameters, a maximum dye removal efficiency of 93.89% and an adsorption capacity of 9.39 mg/g were achieved. Reusability assessments showed efficiencies of 85.59% and 78.33% in the first and second cycles, respectively. Adsorption data aligned well with the Freundlich isotherm (R² = 0.9998) and Ho’s pseudo-second-order kinetic model (R² = 0.9958). Thermodynamic findings indicated physisorption as the dominant mechanism. Overall, the green-synthesized ZnO NPs demonstrate significant potential as a low-cost, sustainable adsorbent for dye removal, particularly in resource-limited regions such as Bangladesh.
{"title":"Green Synthesis and Characterization of ZnO Nanoparticles Using Brunfelsia americana Leaf Extract: Isotherm, Kinetics, Thermodynamic Insights and Reusability into Malachite Green Dye Removal from Aqueous Solutions","authors":"Md.Rajibul Akanda, Md. Foysal Hasan, Md. Al-Amin","doi":"10.1016/j.sajce.2025.10.001","DOIUrl":"10.1016/j.sajce.2025.10.001","url":null,"abstract":"<div><div>This study presents the eco-friendly approach for synthesizing zinc oxide nanoparticles (ZnO NPs) using <em>Brunfelsia americana</em> leaf extract as a novel bioreductant, serving dual roles as a reducing and stabilizing agent. The influence of solvent type, calcination conditions, and extract concentration on nanoparticle formation was systematically explored to optimize synthesis efficiency. A distinct color change and a UV–visible absorption peak near 360 nm confirmed the formation of ZnO NPs. Structural and morphological analyses using FTIR, XRD, SEM, and EDX revealed the presence of surface functional groups, a predominantly spherical shape, particle sizes ranging from 35 to 50 nm (average ∼45 nm), elemental composition, and a crystalline hexagonal wurtzite phase with a crystallite size of 36.09 nm and the specific surface area was calculated to be 29.63 m<sup>2</sup>/g (XRD / crystallite-based estimate). The prepared ZnO NPs were evaluated for their ability to adsorb malachite green (MG) dye from aqueous solutions. Optimal adsorption occurred under the conditions: pH<sub>ZPC</sub> of 7.48, solution pH of 8.0, initial dye concentration of 30 mg/L, nanoparticle dosage of 0.3 g/L, contact time of 210 min and agitation speed of 300 rpm. Under these parameters, a maximum dye removal efficiency of 93.89% and an adsorption capacity of 9.39 mg/g were achieved. Reusability assessments showed efficiencies of 85.59% and 78.33% in the first and second cycles, respectively. Adsorption data aligned well with the Freundlich isotherm (R² = 0.9998) and Ho’s pseudo-second-order kinetic model (R² = 0.9958). Thermodynamic findings indicated physisorption as the dominant mechanism. Overall, the green-synthesized ZnO NPs demonstrate significant potential as a low-cost, sustainable adsorbent for dye removal, particularly in resource-limited regions such as Bangladesh.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 11-23"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340931","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 : 2026-01-01Epub 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":"2026-01-01","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号