Pub Date : 2025-11-20DOI: 10.1016/j.sajce.2025.11.016
Luluk Edahwati , Mohammad Tauviqirrahman , Sutiyono , Ferdiyan Tri Prayoga , Syasmitha Lucky Aprillianty , Indah Nur Fauziyyah
Hydroxyapatite is a biomaterial that exhibits similarities to the inorganic mineral constituents present in bones and teeth. Consequently, its significance in the field of orthopedic medicine is substantial. The bioactive nature of hydroxyapatite is very possible as a place for the growth of new bone tissue. This research utilizes the CaO content contained in the shells of thorn clams where the CaO content is 91.08 %. This shell waste can often be found on the Kenjeran coast, Surabaya, East Java, thus the use of thorny clam (Murex trapa) shells is very easy to obtain as a raw material for the formation of hydroxyapatite. The PCC process uses CO2 gas flow with a flow rate of 1 ml/s up to pH 8. Assessment of the research to be carried out on the formation of hydroxyapatite uses a range of pH 5, 9 and 13 and the molar ratio of Ca/P is 1.27; 1.67 and 2.07. From the process, hydroxyapatite was obtained with the highest yield of 96 % under pH 9 conditions with a Ca/P molar ratio of 1.67. FTIR analysis conducted on hydroxyapatite with a Ca/P molar ratio of 1.67 detected the presence of functional groups PO43-, OH-, and CO32-. SEM-EDX analysis performed on hydroxyapatite at pH 9 with a Ca/P molar ratio of 1.67 showed that the crystal structure of hydroxyapatite tends to be spherical and agglomerated.
{"title":"Analysis of the effect Hydroxyapatite formation from Precipitate Calcium Carbonate of thorn shell waste (Murex trapa) with carbonation method","authors":"Luluk Edahwati , Mohammad Tauviqirrahman , Sutiyono , Ferdiyan Tri Prayoga , Syasmitha Lucky Aprillianty , Indah Nur Fauziyyah","doi":"10.1016/j.sajce.2025.11.016","DOIUrl":"10.1016/j.sajce.2025.11.016","url":null,"abstract":"<div><div>Hydroxyapatite is a biomaterial that exhibits similarities to the inorganic mineral constituents present in bones and teeth. Consequently, its significance in the field of orthopedic medicine is substantial. The bioactive nature of hydroxyapatite is very possible as a place for the growth of new bone tissue. This research utilizes the CaO content contained in the shells of thorn clams where the CaO content is 91.08 %. This shell waste can often be found on the Kenjeran coast, Surabaya, East Java, thus the use of thorny clam (Murex trapa) shells is very easy to obtain as a raw material for the formation of hydroxyapatite. The PCC process uses CO<sub>2</sub> gas flow with a flow rate of 1 ml/s up to pH 8. Assessment of the research to be carried out on the formation of hydroxyapatite uses a range of pH 5, 9 and 13 and the molar ratio of Ca/P is 1.27; 1.67 and 2.07. From the process, hydroxyapatite was obtained with the highest yield of 96 % under pH 9 conditions with a Ca/P molar ratio of 1.67. FTIR analysis conducted on hydroxyapatite with a Ca/P molar ratio of 1.67 detected the presence of functional groups PO<sub>4</sub><sup>3-</sup>, OH-, and CO<sub>3</sub><sup>2-</sup>. SEM-EDX analysis performed on hydroxyapatite at pH 9 with a Ca/P molar ratio of 1.67 showed that the crystal structure of hydroxyapatite tends to be spherical and agglomerated.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"56 ","pages":"Article 100800"},"PeriodicalIF":0.0,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189633","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 : 2025-11-20DOI: 10.1016/j.sajce.2025.11.014
Rassol Hamed Rasheed , Moafaq K.S. Al-Ghezi , Mohammed Ali , Ravishankar Sathyamurthy , Mujtaba A. Flayyih , Suhaeb sabbar rahi , Hussein Togun , Ahmed Mouthanna , Davood Domiri Ganji
The flow of Williamson fluid over a stretched sheet serves as a model for various real-world scenarios involving the interaction of non-Newtonian fluids with moving surfaces. Its notable practical applications are in the fields of Polymer Processing, Food Processing, and Biomedical Applications. The primary goal of the proposed model is to investigate the effects of Ohmic heating and viscous dissipation on the bidirectional flow of Williamson and micropolar fluids within a porous medium over an extending surface. This study is novel in that it employs the FEM(Finite Element Method) approach to analyze the numerical values of the fluid and thermal characteristics of an incompressible convective flow over a flat surface for the first time. Another novel aspect of this work is the investigation of Arrhenius function terms and magnetic forces in moving fluid flow. Heat convection and velocity slip at the surface are also examined. The mathematical model of the problem results in higher-order, nonlinear ordinary differential equations through the appropriate combination of variables. The Finite Element Method is used to solve the given nonlinear system of differential equations. The present study has revealed several significant insights, notably that skin friction increases with the enhancement of porosity, as well as the characteristics of Williamson fluids and micropolar fluids. Flow patterns are analyzed and visualized by examining and graphing various components that result from the analysis. As the slip parameter increases, the velocity field decreases in the x-direction. As the heat transfer of the Williamson fluid flowing over the stretched sheet increases at k = 3, its velocity is approximately 45.55 % greater compared to the k = 1 case under the lowest heat transfer condition. The velocity in the x-direction decreases as the slip parameter increases. Additionally, it has been observed that the concentration of the Williamson fluid decreases, while the temperature distribution increases with higher Eckert number values.
{"title":"Investigation of the two-way movement of Williamson micropolar fluid in a porous medium with consideration of activation energy and thermal radiation","authors":"Rassol Hamed Rasheed , Moafaq K.S. Al-Ghezi , Mohammed Ali , Ravishankar Sathyamurthy , Mujtaba A. Flayyih , Suhaeb sabbar rahi , Hussein Togun , Ahmed Mouthanna , Davood Domiri Ganji","doi":"10.1016/j.sajce.2025.11.014","DOIUrl":"10.1016/j.sajce.2025.11.014","url":null,"abstract":"<div><div>The flow of Williamson fluid over a stretched sheet serves as a model for various real-world scenarios involving the interaction of non-Newtonian fluids with moving surfaces. Its notable practical applications are in the fields of Polymer Processing, Food Processing, and Biomedical Applications. The primary goal of the proposed model is to investigate the effects of Ohmic heating and viscous dissipation on the bidirectional flow of Williamson and micropolar fluids within a porous medium over an extending surface. <strong>This study is novel in that it employs the FEM(Finite Element Method) approach to analyze the numerical values of the fluid and thermal characteristics of an incompressible convective flow over a flat surface for the first time. Another novel aspect of this work is the investigation of Arrhenius function terms and magnetic forces in moving fluid flow.</strong> Heat convection and velocity slip at the surface are also examined. The mathematical model of the problem results in higher-order, nonlinear ordinary differential equations through the appropriate combination of variables. The Finite Element Method is used to solve the given nonlinear system of differential equations. The present study has revealed several significant insights, notably that skin friction increases with the enhancement of porosity, as well as the characteristics of Williamson fluids and micropolar fluids. Flow patterns are analyzed and visualized by examining and graphing various components that result from the analysis. As the slip parameter increases, the velocity field decreases in the x-direction. As the heat transfer of the Williamson fluid flowing over the stretched sheet increases at k = 3, its velocity is approximately 45.55 % greater compared to the k = 1 case under the lowest heat transfer condition. The velocity in the x-direction decreases as the slip parameter increases. Additionally, it has been observed that the concentration of the Williamson fluid decreases, while the temperature distribution increases with higher Eckert number values.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 285-297"},"PeriodicalIF":0.0,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621203","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 : 2025-11-20DOI: 10.1016/j.sajce.2025.11.015
Peace S. Azeh, Monsurat O. Jimoh, Mabafokeng Masitha, Samuel A. Iwarere, Michael O. Daramola
Biosorption has demonstrated effectiveness in eliminating contaminants of emerging concern (CECs) that lack inclusion in current water quality standards. These pollutants impede progress towards UN Sustainable Development Goals 6 and 14, pertaining to clean water accessibility and marine life preservation. This research investigated the adsorption potential of the persistent pharmaceutical pollutant, carbamazepine, using Moringa oleifera (MO) seed coat. This research investigated the adsorption potential of the persistent pharmaceutical pollutant, carbamazepine, using MO seed coat biochar. Acid hydrolysis and subsequent carbonization produced a biochar with superior properties for adsorption as confirmed by FTIR, SEM, EDX, CHNOS, and XRD analyses. The influence of agitation speed (200 rpm, 300 rpm, and 400 rpm), adsorption duration (0 to 180 min), and adsorption temperature (30 °C, 40 °C, and 50 °C) on CBZ removal in synthetic wastewater were studied.
The quadratic regression model obtained from Box Behnken experimental design (BBD) with Response surface methodology (RSM) showed a strong predictive ability with R² = 0.9754 and adjusted-R² = 0.9015. Agitation speed significantly influenced the adsorption capacity as evidenced by a p-value of 0.02848. The optimum conditions for CBZ adsorption were 400 rpm, 30 °C, and 2.15 h at which a maximum adsorption capacity of 51.87 mg/g was anticipated. The adsorption behaviour was best described by pseudo-second order kinetics and the Temkin isotherm model. The study confirmed that MO seed coat biochar as a promising green adsorbent for pharmaceutical contaminant removal in wastewater treatment.
{"title":"Adsorptive removal of Carbamazepine from synthetic wastewater using Moringa oleifera seed coat","authors":"Peace S. Azeh, Monsurat O. Jimoh, Mabafokeng Masitha, Samuel A. Iwarere, Michael O. Daramola","doi":"10.1016/j.sajce.2025.11.015","DOIUrl":"10.1016/j.sajce.2025.11.015","url":null,"abstract":"<div><div>Biosorption has demonstrated effectiveness in eliminating contaminants of emerging concern (CECs) that lack inclusion in current water quality standards. These pollutants impede progress towards UN Sustainable Development Goals 6 and 14, pertaining to clean water accessibility and marine life preservation. This research investigated the adsorption potential of the persistent pharmaceutical pollutant, carbamazepine, using <em>Moringa oleifera</em> (MO) seed coat. This research investigated the adsorption potential of the persistent pharmaceutical pollutant, carbamazepine, using MO seed coat biochar. Acid hydrolysis and subsequent carbonization produced a biochar with superior properties for adsorption as confirmed by FTIR, SEM, EDX, CHNOS, and XRD analyses. The influence of agitation speed (200 rpm, 300 rpm, and 400 rpm), adsorption duration (0 to 180 min), and adsorption temperature (30 °C, 40 °C, and 50 °C) on CBZ removal in synthetic wastewater were studied.</div><div>The quadratic regression model obtained from Box Behnken experimental design (BBD) with Response surface methodology (RSM) showed a strong predictive ability with R² = 0.9754 and adjusted-R² = 0.9015. Agitation speed significantly influenced the adsorption capacity as evidenced by a p-value of 0.02848. The optimum conditions for CBZ adsorption were 400 rpm, 30 °C, and 2.15 h at which a maximum adsorption capacity of 51.87 mg/g was anticipated. The adsorption behaviour was best described by pseudo-second order kinetics and the Temkin isotherm model. The study confirmed that MO seed coat biochar as a promising green adsorbent for pharmaceutical contaminant removal in wastewater treatment.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 368-379"},"PeriodicalIF":0.0,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736214","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 : 2025-11-19DOI: 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":"2025-11-19","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}
Pub Date : 2025-11-17DOI: 10.1016/j.sajce.2025.11.012
Muhammadin Hamid , Indri Dayana , Habib Satria , Dadan Ramdan , Junaidi , Muhammad Fadlan Siregar , Dewi Sholeha , Hadi Wijoyo
The preparation of silica-coated magnetite nanoparticles as a lubricant additive has been successfully carried out. The material was prepared using a combination of coprecipitation and ultrasonic methods. In this study, SEM characterization was also performed to support morphological analysis, XRD was performed to determine crystalline properties, and FTIR analysis was performed to help identify functional groups. Based on these characterizations, the silica was successfully coated with magnetite. Then, AAS testing, Viscosity, and lubricant tests were conducted to assess the impact of adding silica-coated magnetite to the lubricant. The stability of lubricants using magnetite, both without and with the addition of TEOS, at a viscosity of 100 °C, is 8.65 mm²/s and 8.96 mm²/s, respectively, for lubricants and nano-lubricants. The total base number showed the exact value of 0.55 in both the lubricant and nano-lubricant, and the contaminant results obtained. In conclusion, additives can produce suitable nano-lubricants.
{"title":"Influence of silica addition in magnetite (Fe3O4) particles on physical properties for the application of nano-lubricant","authors":"Muhammadin Hamid , Indri Dayana , Habib Satria , Dadan Ramdan , Junaidi , Muhammad Fadlan Siregar , Dewi Sholeha , Hadi Wijoyo","doi":"10.1016/j.sajce.2025.11.012","DOIUrl":"10.1016/j.sajce.2025.11.012","url":null,"abstract":"<div><div>The preparation of silica-coated magnetite nanoparticles as a lubricant additive has been successfully carried out. The material was prepared using a combination of coprecipitation and ultrasonic methods. In this study, SEM characterization was also performed to support morphological analysis, XRD was performed to determine crystalline properties, and FTIR analysis was performed to help identify functional groups. Based on these characterizations, the silica was successfully coated with magnetite. Then, AAS testing, Viscosity, and lubricant tests were conducted to assess the impact of adding silica-coated magnetite to the lubricant. The stability of lubricants using magnetite, both without and with the addition of TEOS, at a viscosity of 100 °C, is 8.65 mm²/s and 8.96 mm²/s, respectively, for lubricants and nano-lubricants. The total base number showed the exact value of 0.55 in both the lubricant and nano-lubricant, and the contaminant results obtained. In conclusion, additives can produce suitable nano-lubricants.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 238-243"},"PeriodicalIF":0.0,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621231","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 : 2025-11-17DOI: 10.1016/j.sajce.2025.11.011
Hasan Douha Touki, Md. Nobin Hossain, Ahmed Imtiaz Ferdous, Yaminul Hoque, Mohiuddin Ahmed, Sumon Saha
A two-dimensional T-shaped ventilated chamber under forced convective flow is regulated by a proportional-integral-derivative flow controller in the current research, focusing on improving the hydro-thermal performance. In the complex configurations where heat extraction must adjust dynamically to the fluctuating inflow conditions, preserving effective temperature regulation is vital for several applications, such as compact cooling systems, electronic components cooling, and energy storage units. In this circumstance, a micropolar ferrofluid (Fe3O4-water) circulates through the vented chamber, entering from the left-side inlet port at a fixed room temperature and leaving through the right-side outlet port under ambient conditions. The bottom surfaces are heated, while the top surface of the chamber remains cold. The inflow velocity is regulated based on the feedback from the continuous flow controller. A boundary temperature probe is placed at the system’s outlet port to measure the ferrofluid temperature frequently and send a feedback response to the flow controller. The governing mass, momentum, and energy equations representing micropolar ferrofluid flow and heat transport are resolved using the Galerkin finite element technique, permitting an inclusive computational analysis of the system’s behavior. Controller performance is assessed in terms of rise time, percentage overshoot, and settling time relative to the desired setpoint thermal condition. Subsequently, the parametric simulations are performed for tuning selected flow controller (proportional, integral, and derivative) gains within their range of operation (0.06 ≤ Kp ≤ 0.20 m/sK, 0.005 ≤ Ki ≤ 0.01 m/s2 K, and 0.0005 ≤ Kd ≤ 0.05 m/K) to achieve optimal response characteristics. The discoveries sensibly demonstrate that Kp = 0.06 m/sK, Ki = 0.01 m/s2 K, and Kd = 0.05 m/K are the optimum settings for the selected flow controller’s gains.
{"title":"Thermal management of micropolar ferrofluid forced convective flow in a T-shaped vented chamber via a proportional-integral-derivative controller","authors":"Hasan Douha Touki, Md. Nobin Hossain, Ahmed Imtiaz Ferdous, Yaminul Hoque, Mohiuddin Ahmed, Sumon Saha","doi":"10.1016/j.sajce.2025.11.011","DOIUrl":"10.1016/j.sajce.2025.11.011","url":null,"abstract":"<div><div>A two-dimensional <em>T</em>-shaped ventilated chamber under forced convective flow is regulated by a proportional-integral-derivative flow controller in the current research, focusing on improving the hydro-thermal performance. In the complex configurations where heat extraction must adjust dynamically to the fluctuating inflow conditions, preserving effective temperature regulation is vital for several applications, such as compact cooling systems, electronic components cooling, and energy storage units. In this circumstance, a micropolar ferrofluid (Fe<sub>3</sub>O<sub>4</sub>-water) circulates through the vented chamber, entering from the left-side inlet port at a fixed room temperature and leaving through the right-side outlet port under ambient conditions. The bottom surfaces are heated, while the top surface of the chamber remains cold. The inflow velocity is regulated based on the feedback from the continuous flow controller. A boundary temperature probe is placed at the system’s outlet port to measure the ferrofluid temperature frequently and send a feedback response to the flow controller. The governing mass, momentum, and energy equations representing micropolar ferrofluid flow and heat transport are resolved using the Galerkin finite element technique, permitting an inclusive computational analysis of the system’s behavior. Controller performance is assessed in terms of rise time, percentage overshoot, and settling time relative to the desired setpoint thermal condition. Subsequently, the parametric simulations are performed for tuning selected flow controller (proportional, integral, and derivative) gains within their range of operation (0.06 ≤ <em>K<sub>p</sub></em> ≤ 0.20 m/sK, 0.005 ≤ <em>K<sub>i</sub></em> ≤ 0.01 m/s<sup>2</sup> K, and 0.0005 ≤ <em>K</em><sub>d</sub> ≤ 0.05 m/K) to achieve optimal response characteristics. The discoveries sensibly demonstrate that <em>K<sub>p</sub></em> = 0.06 m/sK, <em>K<sub>i</sub></em> = 0.01 m/s<sup>2</sup> K, and <em>K</em><sub>d</sub> = 0.05 m/K are the optimum settings for the selected flow controller’s gains.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 222-234"},"PeriodicalIF":0.0,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577190","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}
Nanocrystalline ferrites of the Mn1-xZnxFe2O4 system (x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized with varying Mn and Zn contents using a hydrothermal method assisted with Aloe barbadensis Mill (Aloe vera) extract as adsorbent materials in the treatment of water contaminated with an azoic organic dye (Congo red). The obtained nanoferrites were subjected to morphological, magnetic, optical and thermal characterization using SEM, XRD, FTIR, VSM, UV–Vis, DLS and TGA techniques. Nanocrystalline ferrites with a spinel-type structure and crystallite sizes ranging from 19.5 to 42.1 nm were obtained from XRD analysis. Morphological analysis by SEM revealed agglomerates of irregularly shaped particles with nanometric sizes. Magnetic hysteresis curves obtained by VSM showed the magnetically soft behavior of the ferrites, with saturation magnetization values Ms between 37.89 and 8.78 emu/g, which decrease with increasing Zn content. UV–vis spectra confirmed that ferrites absorb primarily in the ultraviolet region and that the band gap energy increased with the addition of Zn. The Congo red dye adsorption tests showed that Mn-Zn ferrites perform well as adsorbents. Of all the compositions, the ferrite with x = 0.0 achieved a dye removal efficiency of 73.65 % across varying the concentration (25 ppm) and contact time (20 min). Likewise, this ferrite with x = 0.0 reached a maximum Congo red adsoprtion of 84 % at pH 5. Meanwhile, the ferrite with x = 1.0 achieved a dye removal efficiency of 74.84 % at pH 7. These results prove that Mn-Zn ferrites synthesized from Aloe vera extract represent a sustainable and efficient alternative for the treatment of water contaminated with the Congo Red dye.
{"title":"Synthesis and characterization of nanocrystalline Mn-Zn ferrites obtained via hydrothermal method using Aloe barbadensis Mill (Asphodelaceae) extract for the treatment of water contaminated with Congo red","authors":"Melissa Quevedo Lopez , Fernanda Pilaquinga , Alexis Debut , Alberto Albis Arrieta , Andrés Rosales Rivera , Zulia Caamaño De Avila","doi":"10.1016/j.sajce.2025.11.010","DOIUrl":"10.1016/j.sajce.2025.11.010","url":null,"abstract":"<div><div>Nanocrystalline ferrites of the Mn<sub>1-x</sub>Zn<sub>x</sub>Fe<sub>2</sub>O<sub>4</sub> system (<em>x</em> = 0, 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized with varying Mn and Zn contents using a hydrothermal method assisted with <em>Aloe barbadensis</em> Mill (Aloe vera) extract as adsorbent materials in the treatment of water contaminated with an azoic organic dye (Congo red). The obtained nanoferrites were subjected to morphological, magnetic, optical and thermal characterization using SEM, XRD, FTIR, VSM, UV–Vis, DLS and TGA techniques. Nanocrystalline ferrites with a spinel-type structure and crystallite sizes ranging from 19.5 to 42.1 nm were obtained from XRD analysis. Morphological analysis by SEM revealed agglomerates of irregularly shaped particles with nanometric sizes. Magnetic hysteresis curves obtained by VSM showed the magnetically soft behavior of the ferrites, with saturation magnetization values Ms between 37.89 and 8.78 emu/g, which decrease with increasing Zn content. UV–vis spectra confirmed that ferrites absorb primarily in the ultraviolet region and that the band gap energy increased with the addition of Zn. The Congo red dye adsorption tests showed that Mn-Zn ferrites perform well as adsorbents. Of all the compositions, the ferrite with <em>x</em> = 0.0 achieved a dye removal efficiency of 73.65 % across varying the concentration (25 ppm) and contact time (20 min). Likewise, this ferrite with <em>x</em> = 0.0 reached a maximum Congo red adsoprtion of 84 % at pH 5. Meanwhile, the ferrite with <em>x</em> = 1.0 achieved a dye removal efficiency of 74.84 % at pH 7. These results prove that Mn-Zn ferrites synthesized from Aloe vera extract represent a sustainable and efficient alternative for the treatment of water contaminated with the Congo Red dye.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 255-270"},"PeriodicalIF":0.0,"publicationDate":"2025-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621204","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 : 2025-11-16DOI: 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":"2025-11-16","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 : 2025-11-15DOI: 10.1016/j.sajce.2025.11.008
Aisyah Alifatul Zahidah Rohmah , Wahyu Meka , Ary Bachtiar Khrisna Putra , Ali Altway , Ardi Nugroho , Tri Widjaja
Coal combustion intensifies carbon emissions, contributing to global warming. This study explores co-firing coal with biomass sources—rice husks, sawdust, and cocopeat—and examines the role of calcium carbonate (CaCO₃) in reducing slagging. The research was conducted in three stages: (1) laboratory-scale analysis for raw material characterization, (2) prototype-scale combustion testing for efficiency and emissions, and (3) full-scale evaluation in a coal-fired power plant. Laboratory tests identified a 50% rice husk (RH) – 50% sawdust (SW) mixture as optimal, with a calorific value of 15,788.324 kJ/kg and a low alkali index (0.11). Prototype testing showed that emissions remained within regulatory limits, and CaCO₃ addition effectively reduced SO₂, NOₓ, and CO emissions while increasing SO₃ and SiO₂ retention in bottom ash, mitigating slagging risks. However, CaCO₃ exhibited limited and inconsistent effectiveness, making it unsuitable for large-scale application. Full-scale trials demonstrated that co-firing improved boiler efficiency (83.46% with 5% biomass – 95% coal co-firing vs. 83.65% with 100% coal), with stable power output (396–400 MW) and a fuel consumption of 0.6 kg/kWh. Sawdust contributed to combustion stability due to its lower porosity, while rice husks enhanced airflow, accelerating combustion. Slagging and fouling indices indicated a high slagging potential (category 6) for sawdust and cocopeat, but mixed biomass variables exhibited reduced slagging risk (category 5). Cocopeat had the highest sodium fouling and slagging indices (1.41, 1.54, 1.56), making it unsuitable for co-firing. Community involvement in biomass procurement engaged 266 stakeholders, though seasonal limitations required external sourcing. Additionally, training programs in organic fertilizer production were implemented to support biomass sustainability. Overall, this study demonstrates that biomass–coal co-firing represents a viable pathway for cleaner energy production that simultaneously provides economic and environmental benefits.
{"title":"Engineering study of coal co-firing based on biomass mixture and slagging-fouling control in the steam power plant","authors":"Aisyah Alifatul Zahidah Rohmah , Wahyu Meka , Ary Bachtiar Khrisna Putra , Ali Altway , Ardi Nugroho , Tri Widjaja","doi":"10.1016/j.sajce.2025.11.008","DOIUrl":"10.1016/j.sajce.2025.11.008","url":null,"abstract":"<div><div>Coal combustion intensifies carbon emissions, contributing to global warming. This study explores co-firing coal with biomass sources—rice husks, sawdust, and cocopeat—and examines the role of calcium carbonate (CaCO₃) in reducing slagging. The research was conducted in three stages: (1) laboratory-scale analysis for raw material characterization, (2) prototype-scale combustion testing for efficiency and emissions, and (3) full-scale evaluation in a coal-fired power plant. Laboratory tests identified a 50% rice husk (RH) – 50% sawdust (SW) mixture as optimal, with a calorific value of 15,788.324 kJ/kg and a low alkali index (0.11). Prototype testing showed that emissions remained within regulatory limits, and CaCO₃ addition effectively reduced SO₂, NOₓ, and CO emissions while increasing SO₃ and SiO₂ retention in bottom ash, mitigating slagging risks. However, CaCO₃ exhibited limited and inconsistent effectiveness, making it unsuitable for large-scale application. Full-scale trials demonstrated that co-firing improved boiler efficiency (83.46% with 5% biomass – 95% coal co-firing vs. 83.65% with 100% coal), with stable power output (396–400 MW) and a fuel consumption of 0.6 kg/kWh. Sawdust contributed to combustion stability due to its lower porosity, while rice husks enhanced airflow, accelerating combustion. Slagging and fouling indices indicated a high slagging potential (category 6) for sawdust and cocopeat, but mixed biomass variables exhibited reduced slagging risk (category 5). Cocopeat had the highest sodium fouling and slagging indices (1.41, 1.54, 1.56), making it unsuitable for co-firing. Community involvement in biomass procurement engaged 266 stakeholders, though seasonal limitations required external sourcing. Additionally, training programs in organic fertilizer production were implemented to support biomass sustainability. Overall, this study demonstrates that biomass–coal co-firing represents a viable pathway for cleaner energy production that simultaneously provides economic and environmental benefits.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 191-221"},"PeriodicalIF":0.0,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577225","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 : 2025-11-13DOI: 10.1016/j.sajce.2025.11.007
Samia Akter , Mohammad Al Shahriar Khan , Umme Habiba Bodrun Naher
Chrome tanning, though efficient, contributes significantly to environmental pollution through toxic chromium discharge, threatening water, soil, and ecosystems, thereby highlighting the need for sustainable tanning alternatives. Vegetable tanning is a natural option, but it often produces leather with lower mechanical strength and thermal resistance, limiting its use in demanding applications. This study explores an eco-friendly combination tanning approach using vegetable tannin as the primary tanning agent, followed by retanning with aldehyde, aluminum salts, vegetable tannin, and titanium salts to produce high-quality shoe upper leather with minimal environmental impact. The combination-tanned leathers demonstrated superior mechanical properties compared to full vegetable-tanned leather, with tensile strength of 260 – 275 kg/cm², elongation of 41 – 47 %, stitch tear strength of 119 – 155 kg/cm, tongue tear strength up to 55 kg/cm, bond strength of 590 –630 g/cm, grain crack load up to 29 kg, and distension up to 8.8 mm. Shrinkage temperature was also improved, confirming enhanced thermal stability. Slight reductions were observed in color rub fastness and water vapor permeability, attributed to the compact collagen structure and reduced dye fixation from inorganic retanning agents. SEM analysis revealed progressive improvements in fiber alignment, density, and surface smoothness with aldehyde, aluminum, and titanium salts. Environmental assessment of retanning wastewater showed lower BOD, COD, TDS, and TSS compared to vegetable tanning alone, confirming improved retanning agent efficiency and reduced organic load. Overall, the combination tanning method produced shoe upper leather with desirable strength, thermal stability, and environmental compatibility, offering a sustainable alternative to chrome tanning.
{"title":"Evaluation of combination tanning as a sustainable alternative to chrome tanning for shoe upper leather production","authors":"Samia Akter , Mohammad Al Shahriar Khan , Umme Habiba Bodrun Naher","doi":"10.1016/j.sajce.2025.11.007","DOIUrl":"10.1016/j.sajce.2025.11.007","url":null,"abstract":"<div><div>Chrome tanning, though efficient, contributes significantly to environmental pollution through toxic chromium discharge, threatening water, soil, and ecosystems, thereby highlighting the need for sustainable tanning alternatives. Vegetable tanning is a natural option, but it often produces leather with lower mechanical strength and thermal resistance, limiting its use in demanding applications. This study explores an eco-friendly combination tanning approach using vegetable tannin as the primary tanning agent, followed by retanning with aldehyde, aluminum salts, vegetable tannin, and titanium salts to produce high-quality shoe upper leather with minimal environmental impact. The combination-tanned leathers demonstrated superior mechanical properties compared to full vegetable-tanned leather, with tensile strength of 260 – 275 kg/cm², elongation of 41 – 47 %, stitch tear strength of 119 – 155 kg/cm, tongue tear strength up to 55 kg/cm, bond strength of 590 –630 g/cm, grain crack load up to 29 kg, and distension up to 8.8 mm. Shrinkage temperature was also improved, confirming enhanced thermal stability. Slight reductions were observed in color rub fastness and water vapor permeability, attributed to the compact collagen structure and reduced dye fixation from inorganic retanning agents. SEM analysis revealed progressive improvements in fiber alignment, density, and surface smoothness with aldehyde, aluminum, and titanium salts. Environmental assessment of retanning wastewater showed lower BOD, COD, TDS, and TSS compared to vegetable tanning alone, confirming improved retanning agent efficiency and reduced organic load. Overall, the combination tanning method produced shoe upper leather with desirable strength, thermal stability, and environmental compatibility, offering a sustainable alternative to chrome tanning.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 180-190"},"PeriodicalIF":0.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577222","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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