Pub Date : 2026-01-01Epub Date: 2025-11-24DOI: 10.1016/j.sajce.2025.11.020
Cut Fatimah Zuhra, Muhammad Zulham Efendi Sinaga, Rini Hardiyanti, Petronella Tambunan, Mariati Uly Artha, Zeli Amelia Putri, Esra Claudia, Wilza Fithri Azzahra
Technological advancements, particularly in agriculture, have now entered the stage of smart agrarian practices. One of the latest innovations in this practice is controlled-release pesticides. The use of hydrophobic materials can reduce the release rate of pesticides, which has long been an environmental issue. Starch properties can be modified according to needs by substituting the OH group with fatty acids through esterification reactions. In this study, breadfruit starch was modified with various fatty acids using a urea/NaOH solvent. The modified starch was successfully synthesized, as confirmed by FTIR, 1H NMR, TGA, SEM analyses, and also by examining the effects of the degree of substitution (DS), swelling power, and solubility (in water and DMSO). The results showed that starch modified with stearic acid achieved the best solubility value of 17.04 % and the lowest swelling power of 3.25 %, supported by data from other characterizations. The research concluded that the starch modified through esterification resulted in hydrophobic starch, and the method used was found to be optimal.
{"title":"Modification starch of breadfruit (Artocarpus altilis) through esterification reaction with fatty acid as pesticides in controlled-release formulation","authors":"Cut Fatimah Zuhra, Muhammad Zulham Efendi Sinaga, Rini Hardiyanti, Petronella Tambunan, Mariati Uly Artha, Zeli Amelia Putri, Esra Claudia, Wilza Fithri Azzahra","doi":"10.1016/j.sajce.2025.11.020","DOIUrl":"10.1016/j.sajce.2025.11.020","url":null,"abstract":"<div><div>Technological advancements, particularly in agriculture, have now entered the stage of smart agrarian practices. One of the latest innovations in this practice is controlled-release pesticides. The use of hydrophobic materials can reduce the release rate of pesticides, which has long been an environmental issue. Starch properties can be modified according to needs by substituting the OH group with fatty acids through esterification reactions. In this study, breadfruit starch was modified with various fatty acids using a urea/NaOH solvent. The modified starch was successfully synthesized, as confirmed by FTIR, 1H NMR, TGA, SEM analyses, and also by examining the effects of the degree of substitution (DS), swelling power, and solubility (in water and DMSO). The results showed that starch modified with stearic acid achieved the best solubility value of 17.04 % and the lowest swelling power of 3.25 %, supported by data from other characterizations. The research concluded that the starch modified through esterification resulted in hydrophobic starch, and the method used was found to be optimal.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 618-625"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976168","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: 2025-11-29DOI: 10.1016/j.sajce.2025.11.023
Ida Sriyanti , Muhammad Rama Almafie , Rahma Dani , Leni Marlina , Laida Neti Mulyani , Raisha Syafira Ap Idjan , Meutia Kamilatun Nuha Ap Idjan , Yuli Kurniawati
The electrospinning process offers a versatile platform for fabricating polymer-based nanofibers; however, precise parameter optimization is essential to achieve desirable morphology and performance. This study focuses on optimizing the coaxial electrospinning parameters for PCL/PVP nanofiber fabrication using Response Surface Methodology (RSM). A quadratic regression model was established to assess the combined effects of PCL concentration (10–15% w/v), PVP concentration (10–15% w/v), collector distance (120–160 mm), and applied voltage (12–20 kV) on nanofiber diameter. Statistical analysis confirmed the model’s robustness and predictive accuracy (p < 0.0001; R² = 0.9995; Adjusted R² = 0.9990; Predicted R² = 0.9983). The optimized condition yielded nanofibers with an average diameter of 526 nm and uniform morphology. Mechanical characterization indicated balanced tensile properties (tensile strength ∼10 MPa; elongation at break ∼5%; Young’s modulus 49–51 MPa), while surface wettability tests revealed improved hydrophilicity with a water contact angle of 70–79° FTIR analysis identified intermolecular hydrogen bonding between PCL and PVP, and XRD confirmed a semi-crystalline structure with crystallinity of 33–37%. The findings demonstrate that RSM is an effective statistical tool for process optimization in coaxial electrospinning, enabling systematic control over nanofiber morphology and performance. This optimized approach provides a reliable framework for designing composite nanofibers with tunable structural and physicochemical properties, supporting their potential use in biomedical and materials engineering applications.
{"title":"Optimization of PVP/PCL nanofiber diameter using coaxial electrospinning: response surface methodology and physicochemical characterization","authors":"Ida Sriyanti , Muhammad Rama Almafie , Rahma Dani , Leni Marlina , Laida Neti Mulyani , Raisha Syafira Ap Idjan , Meutia Kamilatun Nuha Ap Idjan , Yuli Kurniawati","doi":"10.1016/j.sajce.2025.11.023","DOIUrl":"10.1016/j.sajce.2025.11.023","url":null,"abstract":"<div><div>The electrospinning process offers a versatile platform for fabricating polymer-based nanofibers; however, precise parameter optimization is essential to achieve desirable morphology and performance. This study focuses on optimizing the coaxial electrospinning parameters for PCL/PVP nanofiber fabrication using Response Surface Methodology (RSM). A quadratic regression model was established to assess the combined effects of PCL concentration (10–15% w/v), PVP concentration (10–15% w/v), collector distance (120–160 mm), and applied voltage (12–20 kV) on nanofiber diameter. Statistical analysis confirmed the model’s robustness and predictive accuracy (<em>p</em> < 0.0001; R² = 0.9995; Adjusted R² = 0.9990; Predicted R² = 0.9983). The optimized condition yielded nanofibers with an average diameter of 526 nm and uniform morphology. Mechanical characterization indicated balanced tensile properties (tensile strength ∼10 MPa; elongation at break ∼5%; Young’s modulus 49–51 MPa), while surface wettability tests revealed improved hydrophilicity with a water contact angle of 70–79° FTIR analysis identified intermolecular hydrogen bonding between PCL and PVP, and XRD confirmed a semi-crystalline structure with crystallinity of 33–37%. The findings demonstrate that RSM is an effective statistical tool for process optimization in coaxial electrospinning, enabling systematic control over nanofiber morphology and performance. This optimized approach provides a reliable framework for designing composite nanofibers with tunable structural and physicochemical properties, supporting their potential use in biomedical and materials engineering applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 298-315"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680948","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: 2025-11-16DOI: 10.1016/j.sajce.2025.11.009
Caglar Berkel, Oguz Özbek
{"title":"The untapped potential of highly selective potentiometric cholesterol biosensors for the screening and monitoring of cholesterol concentrations in body fluids including serum","authors":"Caglar Berkel, Oguz Özbek","doi":"10.1016/j.sajce.2025.11.009","DOIUrl":"10.1016/j.sajce.2025.11.009","url":null,"abstract":"","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 235-237"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577191","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: 2025-11-10DOI: 10.1016/j.sajce.2025.11.006
Md. Khalid Hossain Shishir , Md. Ashraful Alam , Raton Kumar Bishwas , Mohammad Minnatul Karim , S.M. Nur Alam , Gazi Md. Arifuzzaman Khan
A unique sol-gel method was employed to synthesize high-purity copper oxide nanoparticles (CuO NPs) using starch as a natural stabilizer and citric acid as a gelling agent, enabling precise control over nucleation, growth and structural integrity. The synthesized CuO NPs were analyzed utilizing various techniques, including X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV–Vis spectroscopy, Dynamic Light Scattering, Zeta potential, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy. XRD analysis validated monoclinic crystal structure with average crystallite size of 21.72 nm and 100 % CuO purity, while SEM revealed uniformly spherical particles. FTIR spectroscopy showed distinct absorption bands at 598.49 cm⁻¹ and 532.83 cm⁻¹ for Cu–O stretching and UV–Vis analysis indicated an absorption peak at 392.08 nm with a 2.01 eV band gap, suggesting sunlight-driven photocatalytic potential. The measured zeta potential of +27.92 mV indicates moderate colloidal stability. The CuO NPs exhibited antibacterial activity against Staphylococcus aureus while no inhibitory effect was observed against multi-drug resistant Escherichia coli. The photocatalytic performance was evaluated through sunlight-assisted degradation of methylene blue, achieving an efficiency of about 88 % within 210 min. This study aims to synthesize high-purity, well-dispersed CuO NPs for precise control over structure and stability. The work’s impact lies in showcasing bio-assisted CuO NPs as efficient sunlight-driven photocatalysts and effective antibacterial agents, highlighting their promise for sustainable environmental and biomedical applications.
以淀粉为天然稳定剂，柠檬酸为胶凝剂，采用独特的溶胶-凝胶法合成了高纯氧化铜纳米颗粒（CuO NPs），实现了对成核、生长和结构完整性的精确控制。利用x射线衍射（XRD）、傅里叶变换红外（FTIR）、紫外可见光谱（UV-Vis）、动态光散射、Zeta电位、扫描电子显微镜（SEM）和能量色散x射线光谱等技术对合成的CuO NPs进行了分析。XRD分析证实了单斜晶的结构，平均晶粒尺寸为21.72 nm， CuO纯度为100%，SEM显示为均匀的球形颗粒。FTIR光谱显示Cu-O在598.49 cm -⁻¹和532.83 cm -⁻¹处有明显的吸收谱带，UV-Vis分析显示吸收谱峰在392.08 nm处，带隙为2.01 eV，表明有阳光驱动的光催化潜力。zeta电位为+27.92 mV，胶体稳定性中等。CuO NPs对金黄色葡萄球菌具有抑菌活性，对多重耐药大肠杆菌无抑制作用。光催化性能通过日光辅助降解亚甲基蓝来评估，在210分钟内达到约88%的效率。本研究旨在合成高纯度、分散良好的氧化铜纳米粒子，以精确控制其结构和稳定性。这项工作的影响在于展示了生物辅助的CuO NPs作为高效的阳光驱动光催化剂和有效的抗菌剂，突出了它们在可持续环境和生物医学应用方面的前景。
{"title":"Crystallographic insights into copper oxide nanoparticles synthesized via a unique sol-gel method: Antibacterial activity and photocatalytic evaluation","authors":"Md. Khalid Hossain Shishir , Md. Ashraful Alam , Raton Kumar Bishwas , Mohammad Minnatul Karim , S.M. Nur Alam , Gazi Md. Arifuzzaman Khan","doi":"10.1016/j.sajce.2025.11.006","DOIUrl":"10.1016/j.sajce.2025.11.006","url":null,"abstract":"<div><div>A unique sol-gel method was employed to synthesize high-purity copper oxide nanoparticles (CuO NPs) using starch as a natural stabilizer and citric acid as a gelling agent, enabling precise control over nucleation, growth and structural integrity. The synthesized CuO NPs were analyzed utilizing various techniques, including X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV–Vis spectroscopy, Dynamic Light Scattering, Zeta potential, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy. XRD analysis validated monoclinic crystal structure with average crystallite size of 21.72 nm and 100 % CuO purity, while SEM revealed uniformly spherical particles. FTIR spectroscopy showed distinct absorption bands at 598.49 cm⁻¹ and 532.83 cm⁻¹ for Cu–O stretching and UV–Vis analysis indicated an absorption peak at 392.08 nm with a 2.01 eV band gap, suggesting sunlight-driven photocatalytic potential. The measured zeta potential of +27.92 mV indicates moderate colloidal stability. The CuO NPs exhibited antibacterial activity against <em>Staphylococcus aureus</em> while no inhibitory effect was observed against multi-drug resistant <em>Escherichia coli</em>. The photocatalytic performance was evaluated through sunlight-assisted degradation of methylene blue, achieving an efficiency of about 88 % within 210 min. This study aims to synthesize high-purity, well-dispersed CuO NPs for precise control over structure and stability. The work’s impact lies in showcasing bio-assisted CuO NPs as efficient sunlight-driven photocatalysts and effective antibacterial agents, highlighting their promise for sustainable environmental and biomedical applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 162-179"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577224","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 potential synergistic effects of incorporating gypsum in CO2-assisted gasification of pinewood. The synergistic interaction between pinewood and gypsum enhanced the efficiency of pinewood conversion into syngas, while simultaneously facilitating the conversion of gypsum into chemically valuable substances, such as calcium sulfide. During gasification, pinewood generated substantial quantities of tars and unreactive char. Tars, being compounds of considerable stability, present a significant obstacle in terms of achieving high conversion efficiency. The presence of gypsum increased the syngas yield from the conversion of char and tars. The results presented here empirically examined the impact of varying quantities of gypsum on the production of hydrogen (H2) and syngas during its CO2-assisted gasification with pinewood. The overall yield of syngas increased by up to 11.7 % while the LHV improved by 12.5 % using 16.67 wt.% of gypsum in pinewood. However, increased mass fractions of gypsum to 50 wt.% negatively affected the syngas production and reduced the syngas yield and LHV by 22 % and 21 %, respectively.
{"title":"Effect of gypsum addition on syngas production during CO2-assisted gasification of pinewood","authors":"Athi-enkosi Mavukwana , Kiran Burra , Ashwani Gupta","doi":"10.1016/j.sajce.2025.10.009","DOIUrl":"10.1016/j.sajce.2025.10.009","url":null,"abstract":"<div><div>This study investigates the potential synergistic effects of incorporating gypsum in CO<sub>2</sub>-assisted gasification of pinewood. The synergistic interaction between pinewood and gypsum enhanced the efficiency of pinewood conversion into syngas, while simultaneously facilitating the conversion of gypsum into chemically valuable substances, such as calcium sulfide. During gasification, pinewood generated substantial quantities of tars and unreactive char. Tars, being compounds of considerable stability, present a significant obstacle in terms of achieving high conversion efficiency. The presence of gypsum increased the syngas yield from the conversion of char and tars. The results presented here empirically examined the impact of varying quantities of gypsum on the production of hydrogen (H<sub>2</sub>) and syngas during its CO<sub>2</sub>-assisted gasification with pinewood. The overall yield of syngas increased by up to 11.7 % while the LHV improved by 12.5 % using 16.67 wt.% of gypsum in pinewood. However, increased mass fractions of gypsum to 50 wt.% negatively affected the syngas production and reduced the syngas yield and LHV by 22 % and 21 %, respectively.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 92-99"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467800","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}
Microplastics pose a significant environmental threat, particularly to aquatic ecosystems. Removing microplastics from water is a critical challenge due to their small size and widespread presence. In this study, the separation of polystyrene (PS) and polyethylene terephthalate (PET) microplastics in hydrocyclones was investigated using Computational Fluid Dynamics (CFD) simulations. A three-dimensional Eulerian-Eulerian multiphase model was employed to simulate the separation process, with water, air, and microplastics. The model demonstrated good agreement results, confirming the reliability of the simulation results. Two factors affecting hydrocyclone performance were investigated. The base hydrocyclone model was scaled down using factors ranging from 1.0 to 0.2 to investigate how size reduction influenced separation efficiency. The results showed that smaller hydrocyclones enhanced recovery (PS: 5.88 to 7.64%; PET: 7.79 to 14.86%) due to stronger centrifugal forces, while higher inlet velocities improved recovery but increased the pressure drop from 49 to 59 kPa, indicating a clear trade-off between separation efficiency and energy consumption. This increase was attributed to the higher centrifugal forces generated in smaller hydrocyclones, which more effectively pushed particles toward the walls, enhancing separation based on density. In addition, higher inlet velocities improved microplastic recovery by amplifying the centrifugal forces within the hydrocyclone, but this came at the cost of increased pressure drop and energy losses due to intensified turbulence and friction.
{"title":"Effect of hydrocyclone size on microplastics separation: a computational fluid dynamics investigation","authors":"Dulyapat Thiemsakul , Shibo Kuang , Wiwittawin Sukmas , Eakarach Bumrungthaichaichan , Krittin Korkerd , Ratchanon Piemjaiswang , Pornpote Piumsomboon , Benjapon Chalermsinsuwan","doi":"10.1016/j.sajce.2025.11.001","DOIUrl":"10.1016/j.sajce.2025.11.001","url":null,"abstract":"<div><div>Microplastics pose a significant environmental threat, particularly to aquatic ecosystems. Removing microplastics from water is a critical challenge due to their small size and widespread presence. In this study, the separation of polystyrene (PS) and polyethylene terephthalate (PET) microplastics in hydrocyclones was investigated using Computational Fluid Dynamics (CFD) simulations. A three-dimensional Eulerian-Eulerian multiphase model was employed to simulate the separation process, with water, air, and microplastics. The model demonstrated good agreement results, confirming the reliability of the simulation results. Two factors affecting hydrocyclone performance were investigated. The base hydrocyclone model was scaled down using factors ranging from 1.0 to 0.2 to investigate how size reduction influenced separation efficiency. The results showed that smaller hydrocyclones enhanced recovery (PS: 5.88 to 7.64%; PET: 7.79 to 14.86%) due to stronger centrifugal forces, while higher inlet velocities improved recovery but increased the pressure drop from 49 to 59 kPa, indicating a clear trade-off between separation efficiency and energy consumption. This increase was attributed to the higher centrifugal forces generated in smaller hydrocyclones, which more effectively pushed particles toward the walls, enhancing separation based on density. In addition, higher inlet velocities improved microplastic recovery by amplifying the centrifugal forces within the hydrocyclone, but this came at the cost of increased pressure drop and energy losses due to intensified turbulence and friction.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 100-110"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467799","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: 2025-11-05DOI: 10.1016/j.sajce.2025.11.002
A. Anantpinijwatna
This study examines the integration of the gallery-walk active learning strategy into a third-year Process Simulation course. Using a quasi-experimental design, student performance was compared across two traditional lecture cohorts (n = 157) and two gallery-walk cohorts (n = 158). Direct analysis revealed the gallery-walk was associated with improved performance on simple simulation problems, with the average percentage of correct answers rising from 63 % to 70 %. However, a performance decline on complex problems was observed in the initial implementation; this was mitigated in the second iteration by adding an instructor-led summarization phase. Notably, the intervention did not increase the number of top-performing students (scores >90 %), a finding potentially explained by the expertise reversal effect. Anonymous surveys indicated a significant increase in student satisfaction and engagement. This study demonstrates the gallery-walk's potential in engineering education but underscores the necessity of iterative refinement to address complex problem-solving and support learners at all proficiency levels.
{"title":"Effects of gallery-walk in process simulation course","authors":"A. Anantpinijwatna","doi":"10.1016/j.sajce.2025.11.002","DOIUrl":"10.1016/j.sajce.2025.11.002","url":null,"abstract":"<div><div>This study examines the integration of the gallery-walk active learning strategy into a third-year Process Simulation course. Using a quasi-experimental design, student performance was compared across two traditional lecture cohorts (<em>n</em> = 157) and two gallery-walk cohorts (<em>n</em> = 158). Direct analysis revealed the gallery-walk was associated with improved performance on simple simulation problems, with the average percentage of correct answers rising from 63 % to 70 %. However, a performance decline on complex problems was observed in the initial implementation; this was mitigated in the second iteration by adding an instructor-led summarization phase. Notably, the intervention did not increase the number of top-performing students (scores >90 %), a finding potentially explained by the expertise reversal effect. Anonymous surveys indicated a significant increase in student satisfaction and engagement. This study demonstrates the gallery-walk's potential in engineering education but underscores the necessity of iterative refinement to address complex problem-solving and support learners at all proficiency levels.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 111-118"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467803","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: 2025-11-26DOI: 10.1016/j.sajce.2025.11.022
Anugrah Ricky Wijaya , Rahadian Zainul , Karna Wijaya , Niko Prasetyo , Nur Abdillah Siddiq
A novel class of bead adsorbents derived from waste Acropora coral skeletons, functionalized with various monomers including alginate, graphene oxide (GO), polyvinyl alcohol (PVA), chitosan, cellulose, natural silica, and pure silica, was synthesized, characterized, and evaluated for the adsorption of Pb(II) ions from aqueous solutions. The characterization techniques, including colorimetric analysis and FTIR spectroscopy, revealed characteristic absorption bands at 712.58, 1186, 825, 1470, 3562, 1660, and 1050 cm⁻¹, corresponding to functional groups introduced through modification of the coral skeleton using Ca²⁺ ions as a source. Among the synthesized beads, Ca-Alg-GO, Ca-Alg-PVA, Ca-Alg-Chitosan, and Ca-Alg-Pure SiO₂ exhibited a maximum adsorption capacity of 0.063 mg/g under optimized conditions namely, a contact time of 30 min and an initial Pb(II) concentration of 2 mg/L in batch systems. Kinetic analysis indicated that the adsorption data best fit the pseudo-second-order model (R²≈0.99), suggesting that chemisorption via valence forces involving sharing or exchange of electrons dominates the process. Additionally, the Freundlich isotherm provided a superior fit compared to the Langmuir model for Ca-Alg-PVA, Ca-Alg-GO, Ca-Alg-Celulose, and Ca-Alg-Chitosan beads, with R² values of 0.991, 0.998, 0.997, and 0.984, respectively. These results imply that multilayer adsorption occurs on heterogeneous surfaces. The positive ΔH values confirm that Pb(II) adsorption on these bead adsorbents is endothermic, reflecting strong interactions between Pb(II) ions and negatively charged sites on the bead surfaces.
{"title":"Synthesis and application of modified waste acropora coral skeletons for Pb(II) adsorption: A bead adsorbent perspective","authors":"Anugrah Ricky Wijaya , Rahadian Zainul , Karna Wijaya , Niko Prasetyo , Nur Abdillah Siddiq","doi":"10.1016/j.sajce.2025.11.022","DOIUrl":"10.1016/j.sajce.2025.11.022","url":null,"abstract":"<div><div>A novel class of bead adsorbents derived from waste Acropora coral skeletons, functionalized with various monomers including alginate, graphene oxide (GO), polyvinyl alcohol (PVA), chitosan, cellulose, natural silica, and pure silica, was synthesized, characterized, and evaluated for the adsorption of Pb(II) ions from aqueous solutions. The characterization techniques, including colorimetric analysis and FTIR spectroscopy, revealed characteristic absorption bands at 712.58, 1186, 825, 1470, 3562, 1660, and 1050 cm⁻¹, corresponding to functional groups introduced through modification of the coral skeleton using Ca²⁺ ions as a source. Among the synthesized beads, Ca-Alg-GO, Ca-Alg-PVA, Ca-Alg-Chitosan, and Ca-Alg-Pure SiO₂ exhibited a maximum adsorption capacity of 0.063 mg/g under optimized conditions namely, a contact time of 30 min and an initial Pb(II) concentration of 2 mg/L in batch systems. Kinetic analysis indicated that the adsorption data best fit the pseudo-second-order model (R²≈0.99), suggesting that chemisorption via valence forces involving sharing or exchange of electrons dominates the process. Additionally, the Freundlich isotherm provided a superior fit compared to the Langmuir model for Ca-Alg-PVA, Ca-Alg-GO, Ca-Alg-Celulose, and Ca-Alg-Chitosan beads, with R² values of 0.991, 0.998, 0.997, and 0.984, respectively. These results imply that multilayer adsorption occurs on heterogeneous surfaces. The positive ΔH values confirm that Pb(II) adsorption on these bead adsorbents is endothermic, reflecting strong interactions between Pb(II) ions and negatively charged sites on the bead surfaces.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 325-338"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681038","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: 2025-12-22DOI: 10.1016/j.sajce.2025.12.013
Maphai Maake, Irvin Noel Booysen, Allen Mambanda
β-Ga2O3 NPs were synthesised hydrothermally and annealed at 1000 °C. Citrate-capped nanocellulose fibres (CNCFs) were extracted from Azanza Garckeana fibres through sequential hydrolysis in 4.1 % citric acid, which had been diluted from a lemon concentrate (pH < 1.5) and 2 % NaOH. The best performing photocatalyst comprising a composite of β-Ga2O3 NPs dispersed onto CNCFs with a 20 % mass (β-Ga2O3/20 % CNCFs) was used for the degradation of methylene blue (MB) at pH 9 and under a 365 nm ultraviolet light irradiation at a radiance of 106 mW cm−2. The mean rate of MB degradation in the presence of β-Ga2O3/20 % CNCFs was 14.1 (±0.5) x 10−3 min−1, in 1.56 mM MB solution, and this was 2 times higher than for β-Ga2O3, which had a rate constant of 7.8 (±0.4) x 10−3 min−1. The rates for both catalysts were slightly lower in a river water spiked at the same level. The β-Ga2O3/20 % CNCFs NPs demonstrated good reusability and stability, allowing for up to 4 cycles, for which the degradation efficiency decreased only by <20 %. Radical capture with specific scavengers suggested positively charged holes (h+), OH•, and O2•- as active species responsible for the photocatalytic redox degradation of MB. Mass spectra of intermittently sampled mixtures from the degradation process revealed the formation of sulphonated amino-phenyl aldehydes and amino-polyphenols as reaction intermediates. These intermediates are colourless, more environmentally benign. A 77 % reduction in the chemical oxygen demand (COD) of a 1.56 mM MB spiked solution upon photodegradation for 3 h, together with the mass spectral data after the reaction, suggested the partial carbon mineralisation of MB to form water and dissolved carbon dioxide.
采用水热法合成β-Ga2O3纳米粒子，并在1000℃下退火。柠檬酸覆盖纳米纤维素纤维（CNCFs）从Azanza Garckeana纤维中通过4.1%柠檬酸的顺序水解提取，柠檬酸从柠檬浓缩液（pH < 1.5）和2% NaOH中稀释。由分散在质量为20%的CNCFs上的β-Ga2O3纳米粒子组成的复合光催化剂（β-Ga2O3/ 20% CNCFs）在pH为9、辐射强度为106 mW cm - 2的365 nm紫外光照射下，用于降解亚甲基蓝（MB）。在1.56 mM MB溶液中，β-Ga2O3/ 20% cncf存在时，MB的平均降解速率为14.1（±0.5）× 10−3 min−1，是β-Ga2O3的2倍，β-Ga2O3的降解速率常数为7.8（±0.4）× 10−3 min−1。两种催化剂的反应速率在同一水平的河水中稍低。β- ga2o3 / 20% CNCFs NPs表现出良好的可重复使用性和稳定性，允许多达4次循环，降解效率仅下降了20%。特定清除剂的自由基捕获表明，带正电的空穴（h+）、OH•和O2•-是光催化氧化还原降解MB的活性物质。降解过程中间歇采样的混合物的质谱显示，磺化氨基苯基醛和氨基多酚作为反应中间体。这些中间体无色，更环保。1.56 mM MB加标溶液在光降解3小时后，化学需氧量（COD）降低77%，结合反应后的质谱数据，表明MB的部分碳矿化形成水和溶解的二氧化碳。
{"title":"UV light-driven photocatalytic degradation of methylene blue with β-Ga2O3 nanoparticles conjugated to nanocellulose extracted from a biowaste fibre","authors":"Maphai Maake, Irvin Noel Booysen, Allen Mambanda","doi":"10.1016/j.sajce.2025.12.013","DOIUrl":"10.1016/j.sajce.2025.12.013","url":null,"abstract":"<div><div>β-Ga<sub>2</sub>O<sub>3</sub> NPs were synthesised hydrothermally and annealed at 1000 °C. Citrate-capped nanocellulose fibres (CNCFs) were extracted from <em>Azanza Garckeana</em> fibres through sequential hydrolysis in 4.1 % citric acid, which had been diluted from a lemon concentrate (pH < 1.5) and 2 % NaOH. The best performing photocatalyst comprising a composite of β-Ga<sub>2</sub>O<sub>3</sub> NPs dispersed onto CNCFs with a 20 % mass (β-Ga<sub>2</sub>O<sub>3</sub>/20 % CNCFs) was used for the degradation of methylene blue (MB) at pH 9 and under a 365 nm ultraviolet light irradiation at a radiance of 106 mW cm<sup>−2</sup>. The mean rate of MB degradation in the presence of β-Ga<sub>2</sub>O<sub>3</sub>/20 % CNCFs was 14.1 (±0.5) x 10<sup>−3</sup> min<sup>−1,</sup> in 1.56 mM MB solution, and this was 2 times higher than for β-Ga<sub>2</sub>O<sub>3,</sub> which had a rate constant of 7.8 (±0.4) x 10<sup>−3</sup> min<sup>−1</sup>. The rates for both catalysts were slightly lower in a river water spiked at the same level. The β-Ga<sub>2</sub>O<sub>3</sub>/20 % CNCFs NPs demonstrated good reusability and stability, allowing for up to 4 cycles, for which the degradation efficiency decreased only by <20 %. Radical capture with specific scavengers suggested positively charged holes (h<sup>+</sup>), OH<sup>•</sup>, and O<sub>2</sub><sup>•-</sup> as active species responsible for the photocatalytic redox degradation of MB. Mass spectra of intermittently sampled mixtures from the degradation process revealed the formation of sulphonated amino-phenyl aldehydes and amino-polyphenols as reaction intermediates. These intermediates are colourless, more environmentally benign. A 77 % reduction in the chemical oxygen demand (COD) of a 1.56 mM MB spiked solution upon photodegradation for 3 h, together with the mass spectral data after the reaction, suggested the partial carbon mineralisation of MB to form water and dissolved carbon dioxide.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 475-492"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839564","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: 2025-12-17DOI: 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":"2026-01-01","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}
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