Pub Date : 2025-08-30DOI: 10.1016/j.sajce.2025.08.016
E.L. Odekanle , O.S. Teniola , I.O. Olaoye , O.A. Falowo , J. Undiandeye
This study investigated the process kinetics of the anaerobic digestion of different wastes under mesophilic conditions. A slurry of cattle dung was anaerobically digested in fabricated 25-litre reactors for 24 days. The biogas volume, physicochemical, and microbial properties of the digesting slurry were determined every three days using standard procedures. Kinetic models based on the first-order, Monod, and Grau second-order expressions were employed to estimate the performance of the process. After the experiment, a cumulative 0.0265 m³ of biogas was produced, and significant variations in the physicochemical and microbial properties of the digestate were observed. The process kinetics of the digestion followed a first-order reaction with a rate constant of 0.0526 day-1 and 75.1 % COD removal efficiency. For the Monod model, the maximum rate of substrate utilization and saturation constant was found to be 0.1107 day-1 and 1326.34 mg/l respectively. Based on analytical parameter, this anaerobic digestion process followed both first-order kinetic and Monod models only, which shows that for maximum biogas production from animal waste, inoculation would be required.
研究了中温条件下不同废物厌氧消化的过程动力学。牛粪浆液在自制的25升反应器中厌氧消化24天。利用标准程序每三天测定一次沼液的沼气量、理化性质和微生物特性。采用基于一阶、Monod和Grau二阶表达式的动力学模型来估计该过程的性能。实验结束后，累计产生了0.0265 m³的沼气，并观察到消化液的理化和微生物特性发生了显著变化。消化过程动力学符合一级反应，速率常数为0.0526 d -1， COD去除率为75.1%。在Monod模型中，底物利用率和饱和常数的最大值分别为0.1107 day-1和1326.34 mg/l。根据分析参数，该厌氧消化过程仅符合一级动力学模型和Monod模型，这表明为了最大限度地利用动物粪便产生沼气，需要接种。
{"title":"Physicochemical characterization and kinetic study of anaerobic digestion of cattle dung in a semi-batch reactor","authors":"E.L. Odekanle , O.S. Teniola , I.O. Olaoye , O.A. Falowo , J. Undiandeye","doi":"10.1016/j.sajce.2025.08.016","DOIUrl":"10.1016/j.sajce.2025.08.016","url":null,"abstract":"<div><div>This study investigated the process kinetics of the anaerobic digestion of different wastes under mesophilic conditions. A slurry of cattle dung was anaerobically digested in fabricated 25-litre reactors for 24 days. The biogas volume, physicochemical, and microbial properties of the digesting slurry were determined every three days using standard procedures. Kinetic models based on the first-order, Monod, and Grau second-order expressions were employed to estimate the performance of the process. After the experiment, a cumulative 0.0265 m³ of biogas was produced, and significant variations in the physicochemical and microbial properties of the digestate were observed. The process kinetics of the digestion followed a first-order reaction with a rate constant of 0.0526 day<sup>-1</sup> and 75.1 % COD removal efficiency. For the Monod model, the maximum rate of substrate utilization and saturation constant was found to be 0.1107 day<sup>-1</sup> and 1326.34 mg/l respectively. Based on analytical parameter, this anaerobic digestion process followed both first-order kinetic and Monod models only, which shows that for maximum biogas production from animal waste, inoculation would be required.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 390-396"},"PeriodicalIF":0.0,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988483","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 : 2025-08-29DOI: 10.1016/j.sajce.2025.08.015
Mario Bonilla-Loor , Liceth Solórzano-Zambrano , Anderson Pazmiño , Diego Segovia-Cedeño , Johnny Delgado-Mera , Miguel Tuárez-Párraga , Ana Aguilar-Paredes , John Molina-Villamar
Predominant among the mangroves of the northern coast of Ecuador, the black mangrove (Avicennia germinans) has been traditionally used in medicine. This study focuses on its phytochemical characterization and antioxidant activity. Bark, leaves, seeds, and roots were washed, dried at 35 °C for 96 h until reaching a moisture content of 10 ± 2 %, and ground. Extracts were obtained by macerating the plant material (1:10 ratio) with sterile water or 96 % ethanol, followed by ultrasound-assisted extraction at 35 °C for 1 h and further maceration at 35 ± 1 °C for 24 h. Qualitative phytochemical screening identified secondary metabolites such as alkaloids, tannins, flavonoids, and saponins, while total phenol content was quantified using the Folin-Ciocalteu method. Antioxidant activity was evaluated using the DPPH and ABTS assays. Aqueous extracts showed higher phenol concentrations, with the bark extract containing 629.5 ± 10.44 mg GAE·g⁻¹. The roots exhibited the highest antioxidant activity, with 21,171.73 µmol Trolox equivalents g⁻¹ (DPPH) and 13,512.00 µmol Trolox equivalents g⁻¹ (ABTS). The antioxidant activity values exhibited statistically significant differences among the extracts and relative to other plant species. The differences in metabolite concentration and antioxidant activity among plant parts and solvents are attributed to physiological adaptation and selective mobility of compounds within the plant. These findings confirm that A. germinans is a valuable source of bioactive compounds with therapeutic and antioxidant properties, supporting its potential use in the development of antioxidant-based formulations. Moreover, these results provide key information for mangrove conservation and its potencial application in pharmaceutical, nutraceutical, and environmental sectors.
{"title":"Phytochemical characterization and antioxidant potential of black mangrove (Avicennia germinans L.) from the northern coast of Ecuador using aqueous and ethanolic extraction","authors":"Mario Bonilla-Loor , Liceth Solórzano-Zambrano , Anderson Pazmiño , Diego Segovia-Cedeño , Johnny Delgado-Mera , Miguel Tuárez-Párraga , Ana Aguilar-Paredes , John Molina-Villamar","doi":"10.1016/j.sajce.2025.08.015","DOIUrl":"10.1016/j.sajce.2025.08.015","url":null,"abstract":"<div><div>Predominant among the mangroves of the northern coast of Ecuador, the black mangrove (<em>Avicennia germinans)</em> has been traditionally used in medicine. This study focuses on its phytochemical characterization and antioxidant activity. Bark, leaves, seeds, and roots were washed, dried at 35 °C for 96 h until reaching a moisture content of 10 ± 2 %, and ground. Extracts were obtained by macerating the plant material (1:10 ratio) with sterile water or 96 % ethanol, followed by ultrasound-assisted extraction at 35 °C for 1 h and further maceration at 35 ± 1 °C for 24 h. Qualitative phytochemical screening identified secondary metabolites such as alkaloids, tannins, flavonoids, and saponins, while total phenol content was quantified using the Folin-Ciocalteu method. Antioxidant activity was evaluated using the DPPH and ABTS assays. Aqueous extracts showed higher phenol concentrations, with the bark extract containing 629.5 ± 10.44 mg GAE·g⁻¹. The roots exhibited the highest antioxidant activity, with 21,171.73 µmol Trolox equivalents g⁻¹ (DPPH) and 13,512.00 µmol Trolox equivalents g⁻¹ (ABTS). The antioxidant activity values exhibited statistically significant differences among the extracts and relative to other plant species. The differences in metabolite concentration and antioxidant activity among plant parts and solvents are attributed to physiological adaptation and selective mobility of compounds within the plant. These findings confirm that <em>A. germinans</em> is a valuable source of bioactive compounds with therapeutic and antioxidant properties, supporting its potential use in the development of antioxidant-based formulations. Moreover, these results provide key information for mangrove conservation and its potencial application in pharmaceutical, nutraceutical, and environmental sectors.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 451-460"},"PeriodicalIF":0.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145095146","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 : 2025-08-27DOI: 10.1016/j.sajce.2025.08.014
Molly Katlo Keitemoge , Matthew Adah Onu , Olawumi Oluwafolakemi Sadare , Naadhira Seedat , Rishen Roopchund , Kapil Moothi
The growing occurrence of antibiotic residues in South African water systems poses serious environmental and public health risks, owing mostly to pharmaceutical discharge, agricultural runoff, and poor waste management. Conventional water treatment procedures frequently fail to properly remove these micropollutants, needing new predictive and analytical approaches. This review critically investigates the implementation of Artificial Neural Networks (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) models to forecast and optimize antibiotic removal from South African water bodies. To the best of our knowledge, little or no research compares the models' respective performances in the context of the urban water cycle in South Africa. Therefore, this review elaborates on some of the pharmaceuticals (such as diclofenac sodium and tetracycline) that have been studied, as well as the challenges associated with their removal. It also emphasizes studies on modeling and predicting pharmaceutical removal from wastewater using ANN and ANFIS models. Additionally, this review considered the comparisons between ANN and ANFIS models in predicting the removal of emerging contaminants, as well as the challenges and limitations associated with these modeling techniques. The studies established that AI models achieved higher R² and lower error metrics compared to classical statistical or isotherm models.
{"title":"Antibiotic removal in South African water using artificial neural networks and adaptive neuro-fuzzy inference system models: A review","authors":"Molly Katlo Keitemoge , Matthew Adah Onu , Olawumi Oluwafolakemi Sadare , Naadhira Seedat , Rishen Roopchund , Kapil Moothi","doi":"10.1016/j.sajce.2025.08.014","DOIUrl":"10.1016/j.sajce.2025.08.014","url":null,"abstract":"<div><div>The growing occurrence of antibiotic residues in South African water systems poses serious environmental and public health risks, owing mostly to pharmaceutical discharge, agricultural runoff, and poor waste management. Conventional water treatment procedures frequently fail to properly remove these micropollutants, needing new predictive and analytical approaches. This review critically investigates the implementation of Artificial Neural Networks (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) models to forecast and optimize antibiotic removal from South African water bodies. To the best of our knowledge, little or no research compares the models' respective performances in the context of the urban water cycle in South Africa. Therefore, this review elaborates on some of the pharmaceuticals (such as diclofenac sodium and tetracycline) that have been studied, as well as the challenges associated with their removal. It also emphasizes studies on modeling and predicting pharmaceutical removal from wastewater using ANN and ANFIS models. Additionally, this review considered the comparisons between ANN and ANFIS models in predicting the removal of emerging contaminants, as well as the challenges and limitations associated with these modeling techniques. The studies established that AI models achieved higher R² and lower error metrics compared to classical statistical or isotherm models.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 371-389"},"PeriodicalIF":0.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932117","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}
Natural convection within enclosed cavities plays a critical role in heat and mass transfer across a wide range of engineering applications. Buoyancy flows are a fundamental aspect of many optimized systems currently deployed, including passive cooling of electronic devices, thermoregulation of solar collectors, and insulation of buildings to store energy used by aerospace systems. Recent advancements in nanofluids, magnetohydrodynamics (MHD), and smart materials have increased the functional applicability of natural-convection-based systems, and modern forms of the Finite Element Method (FEM) have become essential in the accurate modelling of heat and fluid flow in geometrically complex enclosures. The review explores the dynamic fields in detail but with particular focus on how they are applicable in heat exchangers in industry, microfluidic devices, biomedical incubators, and environmental ventilation systems. The review further explores localized heat sources, vortex formation due to embedded obstacles, porous media effects, and the synergistic influence of thermal and magnetic fields. This review investigates how integrating the Finite Element Method (FEM) with artificial intelligence, entropy-based optimization, and experimental validation can transform the design and advancement of next-generation thermal management systems. The findings underscore FEM’s utility as a multi-physics simulation tool for real-world thermal challenges, with particular relevance to South Africa’s growing demand for energy-efficient buildings, renewable energy solutions, and sustainable manufacturing technologies.
{"title":"A comprehensive review on natural convection in various shaped enclosures by FEM: Engineering applications","authors":"Asif Hasan, Mohammad Mokaddes Ali, Shakhawat Hossain, Neamul Haque Siam, Asaduzzaman Rony, Al-Amin Shohan","doi":"10.1016/j.sajce.2025.08.009","DOIUrl":"10.1016/j.sajce.2025.08.009","url":null,"abstract":"<div><div>Natural convection within enclosed cavities plays a critical role in heat and mass transfer across a wide range of engineering applications. Buoyancy flows are a fundamental aspect of many optimized systems currently deployed, including passive cooling of electronic devices, thermoregulation of solar collectors, and insulation of buildings to store energy used by aerospace systems. Recent advancements in nanofluids, magnetohydrodynamics (MHD), and smart materials have increased the functional applicability of natural-convection-based systems, and modern forms of the Finite Element Method (FEM) have become essential in the accurate modelling of heat and fluid flow in geometrically complex enclosures. The review explores the dynamic fields in detail but with particular focus on how they are applicable in heat exchangers in industry, microfluidic devices, biomedical incubators, and environmental ventilation systems. The review further explores localized heat sources, vortex formation due to embedded obstacles, porous media effects, and the synergistic influence of thermal and magnetic fields. This review investigates how integrating the Finite Element Method (FEM) with artificial intelligence, entropy-based optimization, and experimental validation can transform the design and advancement of next-generation thermal management systems. The findings underscore FEM’s utility as a multi-physics simulation tool for real-world thermal challenges, with particular relevance to South Africa’s growing demand for energy-efficient buildings, renewable energy solutions, and sustainable manufacturing technologies.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 308-334"},"PeriodicalIF":0.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888714","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 : 2025-08-23DOI: 10.1016/j.sajce.2025.08.013
Hassan Johnson Kalilo , Joyce Elisadiki , Maheswara Rao Vegi , Said Ali Hamad Vuai
Safe water is a vital component of human life that requires purification to reduce the concentration of ionic pollutants using appropriate water treatment techniques, such as capacitive deionization (CDI) water treatment technology. The porous activated carbon electrode materials have prepared via the carbonization of water hyacinth plants followed by chemical activation using KOH at different temperatures (400-700°C with an increment of 100°C) labeled as CWH-400, WHAC-500, WHAC-600 and WHAC-700 all being activated for 1 h where CWH represents carbonized water hyacinths and WHAC represents water hyacinths activated carbon. The activation temperature has a significant effect on the specific surface area of the porous carbon prepared, as it increases from 464.67 m²/g for CWH-400 to 1020.01 m²/g for WHAC-700. The defluoridation experiments were done using water samples with initial fluoride concentrations of 4.21, 4.61 and 3.51 mg/L for water samples from Arusha (A), Manyara (B) and Shinyanga (C) respectively when the 2 V was supplied to the cell with 10 mL/min flow rate at 3 hours charging time. The defluoridation results were 1.28, 1.37, and 1.15 mg/L for water samples A, B, and C, respectively. The WHAC-700 electrode was found to possess a capacitance of 501.89 F/g, exhibiting removal efficiencies of 69.60%, 70.28%, and 67.24% for water samples from Arusha (A), Manyara (B), and Shinyanga (C), respectively, at a potential of 2 V with a charging time of 3 hours. Therefore, the water hyacinth plants are suitable precursors for preparing porous activated carbon electrodes to be used in a CDI cell for the defluoridation of any water sample.
{"title":"Water hyacinth derived activated carbon electrode materials for water defluoridation using capacitive deionization technology","authors":"Hassan Johnson Kalilo , Joyce Elisadiki , Maheswara Rao Vegi , Said Ali Hamad Vuai","doi":"10.1016/j.sajce.2025.08.013","DOIUrl":"10.1016/j.sajce.2025.08.013","url":null,"abstract":"<div><div>Safe water is a vital component of human life that requires purification to reduce the concentration of ionic pollutants using appropriate water treatment techniques, such as capacitive deionization (CDI) water treatment technology. The porous activated carbon electrode materials have prepared via the carbonization of water hyacinth plants followed by chemical activation using KOH at different temperatures (400-700°C with an increment of 100°C) labeled as CWH-400, WHAC-500, WHAC-600 and WHAC-700 all being activated for 1 h where CWH represents carbonized water hyacinths and WHAC represents water hyacinths activated carbon. The activation temperature has a significant effect on the specific surface area of the porous carbon prepared, as it increases from 464.67 m²/g for CWH-400 to 1020.01 m²/g for WHAC-700. The defluoridation experiments were done using water samples with initial fluoride concentrations of 4.21, 4.61 and 3.51 mg/L for water samples from Arusha (A), Manyara (B) and Shinyanga (C) respectively when the 2 V was supplied to the cell with 10 mL/min flow rate at 3 hours charging time. The defluoridation results were 1.28, 1.37, and 1.15 mg/L for water samples A, B, and C, respectively. The WHAC-700 electrode was found to possess a capacitance of 501.89 F/g, exhibiting removal efficiencies of 69.60%, 70.28%, and 67.24% for water samples from Arusha (A), Manyara (B), and Shinyanga (C), respectively, at a potential of 2 V with a charging time of 3 hours. Therefore, the water hyacinth plants are suitable precursors for preparing porous activated carbon electrodes to be used in a CDI cell for the defluoridation of any water sample.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 357-370"},"PeriodicalIF":0.0,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916379","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 : 2025-08-22DOI: 10.1016/j.sajce.2025.08.012
Mrs.Cecilia M. Botha , Shawn C. Liebenberg , Frederik H. Conradie , Mr.Abraham F. van der Merwe
Statistical methods play a crucial role in the analysis and interpretation of complex data in chemical engineering research. However, parametric statistical approaches may not always suffice in addressing the intricacies of data analysis within design, process modelling and process development. This paper explores the application potential of less conventional statistical methods in the context of chemical engineering. The application potential of these methods will be demonstrated using recent findings from a study conducted on a low-flux flue gas desulphurisation circulating fluidised bed (FGD-CFB). We analysed the solids flux measurements in a novel, low-flux CFB system by using a less conventional statistical technique, the Bland-Altman method, and verifying the findings using the Kruskal-Wallis test. This statistical analysis validated a non-isokinetic solids sampling technique for low-flux dry and semi-dry FGD-CFBs. This case study demonstrates the applicability of this statistical method within chemical engineering, highlighting its potential beyond its traditional use in medical research. Importantly, the focus of this contribution lies not on the specific findings of the case study, but on the methodologies employed therein. This paper aims to be an educational piece to inform the chemical engineering researcher on how and why this less-used-within-engineering statistical method may be applied. It highlights the potential of utilising statistical approaches that are typically used outside the context of engineering in addressing practical engineering challenges. This paper emphasises the applicability of this statistical method in providing valuable insights into complex engineering systems. It is guided by a systematic inquiry aimed at assessing the statistical methods’ suitability for different types of data sets. By embracing this method, chemical engineers can potentially unlock new insights for research and development, facilitating innovation, sustainability, and advancement in the field.
{"title":"The potential of the Bland-Altman method in chemical engineering","authors":"Mrs.Cecilia M. Botha , Shawn C. Liebenberg , Frederik H. Conradie , Mr.Abraham F. van der Merwe","doi":"10.1016/j.sajce.2025.08.012","DOIUrl":"10.1016/j.sajce.2025.08.012","url":null,"abstract":"<div><div>Statistical methods play a crucial role in the analysis and interpretation of complex data in chemical engineering research. However, parametric statistical approaches may not always suffice in addressing the intricacies of data analysis within design, process modelling and process development. This paper explores the application potential of less conventional statistical methods in the context of chemical engineering. The application potential of these methods will be demonstrated using recent findings from a study conducted on a low-flux flue gas desulphurisation circulating fluidised bed (FGD-CFB). We analysed the solids flux measurements in a novel, low-flux CFB system by using a less conventional statistical technique, the Bland-Altman method, and verifying the findings using the Kruskal-Wallis test. This statistical analysis validated a non-isokinetic solids sampling technique for low-flux dry and semi-dry FGD-CFBs. This case study demonstrates the applicability of this statistical method within chemical engineering, highlighting its potential beyond its traditional use in medical research. Importantly, the focus of this contribution lies not on the specific findings of the case study, but on the methodologies employed therein. This paper aims to be an educational piece to inform the chemical engineering researcher on how and why this less-used-within-engineering statistical method may be applied. It highlights the potential of utilising statistical approaches that are typically used outside the context of engineering in addressing practical engineering challenges. This paper emphasises the applicability of this statistical method in providing valuable insights into complex engineering systems. It is guided by a systematic inquiry aimed at assessing the statistical methods’ suitability for different types of data sets. By embracing this method, chemical engineers can potentially unlock new insights for research and development, facilitating innovation, sustainability, and advancement in the field.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 348-356"},"PeriodicalIF":0.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903079","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 : 2025-08-18DOI: 10.1016/j.sajce.2025.08.011
Mohamed A. Hanafy , Rehab M. Ali , Abdallah S. Elgharbawy , Ahmed I. Osman , Mohamed A. Farrag , Abdulaziz H. Al-Anazi
Biodiesel is crucial for mitigating fossil fuel depletion and reducing environmental impacts. Herein, this approach represents a life cycle assessment (LCA) of biodiesel production from waste cooking oil (WCO) utilizing potassium carbonate (K2CO3) as a heterogeneous catalyst instead of potassium hydroxide (KOH), which is the most used catalyst in industry. However, KOH requires a 20% methanol and a 66% reaction time, higher than K2CO3. Besides, KOH is used once, and produces impure biodiesel and glycerol. While K2CO3 can be used, recovered and reused twice, which decreases the net required catalyst amount without a significant decrease in biodiesel production yield, decreases the environmental burdens, and produces purer products. When using WCO or high free fatty acid (FFA) oils, K2CO3 has the advantage of effective direct transesterification, while KOH requires post-treatment process (esterification), which means extra usage of methanol besides the acid catalyst, which is commonly H2SO4, to decrease the FFA content and avoid the saponification reaction. Therefore, this research aims to quantify the environmental burdens of biodiesel production and compare the performance of K2CO3 with that of conventional KOH. Using the ReCiPe method in SimaPro 9.5 software, the LCA adheres to ISO 14040 and 14044 standards. Key findings indicate significant impacts in climate change (0.274 kg CO2,eq), human non-carcinogenic toxicity (0.12 kg 14-DCBeq), terrestrial ecotoxicity (0.536 kg 14-DCBeq), and fossil resource scarcity (0.183 kg oileq). Methanol and K2CO3 are identified as major contributors to environmental burdens. In contrast, KOH demonstrates a less environmental impact compared to K2CO3. The economic study revealed that, for producing 250 thousand tons of biodiesel per year, the total CAPEX needed to build up the plant is around 12 M$ for both catalysts. The results proved that using K2CO3 leads to higher net profits. The study revealed that the biodiesel plant would achieve a remarkable net profit using any type of catalyst, with an advantageous economic indicator for K2CO3 over KOH, proving the high profitability of using K2CO3 as a catalyst.
生物柴油对于缓解化石燃料枯竭和减少环境影响至关重要。在此，该方法代表了从废食用油（WCO）生产生物柴油的生命周期评估（LCA），利用碳酸钾（K2CO3）作为非均相催化剂，而不是氢氧化钾（KOH），氢氧化钾是工业上最常用的催化剂。然而，KOH需要20%的甲醇和66%的反应时间，比K2CO3高。此外，KOH是一次性使用的，产生不纯的生物柴油和甘油。而K2CO3可以二次使用、回收和重复使用，在不显著降低生物柴油产量的情况下，减少了催化剂的净用量，减轻了环境负担，生产出更纯净的产品。当使用WCO或高游离脂肪酸（FFA）油时，K2CO3具有有效的直接酯交换的优势，而KOH则需要后处理（酯化），这意味着除了酸性催化剂（通常为H2SO4）外，还需要额外使用甲醇来降低FFA含量，避免皂化反应。因此，本研究旨在量化生物柴油生产的环境负担，并比较K2CO3与常规KOH的性能。使用SimaPro 9.5软件中的ReCiPe方法，LCA符合ISO 14040和14044标准。主要研究结果表明，气候变化（0.274 kg CO2,eq）、人类非致癌毒性（0.12 kg 14-DCBeq）、陆地生态毒性（0.536 kg 14-DCBeq）和化石资源稀缺（0.183 kg oileq）具有显著影响。甲醇和K2CO3被认为是造成环境负担的主要因素。相比之下，与K2CO3相比，KOH对环境的影响较小。经济研究显示，为了每年生产25万吨生物柴油，建立工厂所需的总资本支出约为1200万美元，用于两种催化剂。结果证明，使用K2CO3可以带来更高的净利润。研究表明，使用任何类型的催化剂，生物柴油装置都能获得显著的净利润，其中K2CO3的经济指标优于KOH，证明了使用K2CO3作为催化剂的高盈利能力。
{"title":"Life cycle assessment of facile applicable biodiesel production","authors":"Mohamed A. Hanafy , Rehab M. Ali , Abdallah S. Elgharbawy , Ahmed I. Osman , Mohamed A. Farrag , Abdulaziz H. Al-Anazi","doi":"10.1016/j.sajce.2025.08.011","DOIUrl":"10.1016/j.sajce.2025.08.011","url":null,"abstract":"<div><div>Biodiesel is crucial for mitigating fossil fuel depletion and reducing environmental impacts. Herein, this approach represents a life cycle assessment (LCA) of biodiesel production from waste cooking oil (WCO) utilizing potassium carbonate (K<sub>2</sub>CO<sub>3</sub>) as a heterogeneous catalyst instead of potassium hydroxide (KOH), which is the most used catalyst in industry. However, KOH requires a 20% methanol and a 66% reaction time, higher than K<sub>2</sub>CO<sub>3</sub>. Besides, KOH is used once, and produces impure biodiesel and glycerol. While K<sub>2</sub>CO<sub>3</sub> can be used, recovered and reused twice, which decreases the net required catalyst amount without a significant decrease in biodiesel production yield, decreases the environmental burdens, and produces purer products. When using WCO or high free fatty acid (FFA) oils, K<sub>2</sub>CO<sub>3</sub> has the advantage of effective direct transesterification, while KOH requires post-treatment process (esterification), which means extra usage of methanol besides the acid catalyst, which is commonly H<sub>2</sub>SO<sub>4</sub>, to decrease the FFA content and avoid the saponification reaction. Therefore, this research aims to quantify the environmental burdens of biodiesel production and compare the performance of K<sub>2</sub>CO<sub>3</sub> with that of conventional KOH. Using the ReCiPe method in SimaPro 9.5 software, the LCA adheres to ISO 14040 and 14044 standards. Key findings indicate significant impacts in climate change (0.274 kg CO<sub>2,eq</sub>), human non-carcinogenic toxicity (0.12 kg 14-DCB<sub>eq</sub>), terrestrial ecotoxicity (0.536 kg 14-DCB<sub>eq</sub>), and fossil resource scarcity (0.183 kg oil<sub>eq</sub>). Methanol and K<sub>2</sub>CO<sub>3</sub> are identified as major contributors to environmental burdens. In contrast, KOH demonstrates a less environmental impact compared to K<sub>2</sub>CO<sub>3</sub>. The economic study revealed that, for producing 250 thousand tons of biodiesel per year, the total CAPEX needed to build up the plant is around 12 M$ for both catalysts. The results proved that using K<sub>2</sub>CO<sub>3</sub> leads to higher net profits. The study revealed that the biodiesel plant would achieve a remarkable net profit using any type of catalyst, with an advantageous economic indicator for K<sub>2</sub>CO<sub>3</sub> over KOH, proving the high profitability of using K<sub>2</sub>CO<sub>3</sub> as a catalyst.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 291-307"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888715","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 study, zinc oxide nanoparticles (ZnO NPs) were eco-friendly synthesized using Verbascum sinaiticum leaf extract (VSPLE). The amount effects such as pH adjusted at (4, 6, 7, 8, 10 and 12), zinc acetate concentration (0.1, 0.2, 0.3, 0.05, and 0.025 M), reaction temperature (20, 40, 60, 80 and 100 °C), reaction time (20,40, 60, 80, 100, 120, and 140 min), and plant extract volume(1, 2, 3, 4, and 5 mL). The synthesized nanoparticles were characterized by using SEM, TGA/DTA, XRD, UV-Vis, and FT-IR spectroscopic techniques. The SEM analysis revealed that the synthesized ZnO NPs exhibited a rod-shaped morphology, and a total weight loss of 15.29 % observed at 24-544 °C in the TGA/DTA analysis, with no further weight loss above 544 °C, confirmed the high thermal stability of ZnO NPs. The XRD analysis confirmed the formation of small sized ZnO NPs with an average crystal size of 52.9 nm. The UV-Vis analysis revealed the absorption of ZnO NPs at 400 nm, and the characteristic band observed in FT-IR analysis at 635 cm⁻¹ for Zn-O stretching confirmed the formation of ZnO NPs. The biosynthesized ZnO NPs demonstrated a significant in vitro antimicrobial activity as evidenced by the inhibition zone sizes against one Gram-positive S. aureus (17.10 ± 0.17) and two Gram-negative bacteria K. pneumoniae (14.17 ± 0.29), and E. coli(12.83 ± 0.29) at 10 mg/mL using the disc diffusion method. It also showed good antifungal activity against Candida ethanolica (6.90 ± 0.10) and Saccharomyces cerevisiae (6.00 ± 0.10), support the potential of plant-mediated nanoparticle synthesis as a promising route for developing biocompatible antimicrobial agents.
{"title":"Green synthesis, characterization, antibacterial, and antifungal activity investigation of zinc oxide nanoparticles using Verbascum Sinaiticum leaf extract","authors":"Berie Kumie , Walelign Wubet , Tadesse Bizuayehu , Hailemichael Tegenu , Melesse Ababay , Aklilu Melese","doi":"10.1016/j.sajce.2025.08.007","DOIUrl":"10.1016/j.sajce.2025.08.007","url":null,"abstract":"<div><div>In this study, zinc oxide nanoparticles (ZnO NPs) were eco-friendly synthesized using <em>Verbascum sinaiticum</em> leaf extract (VSPLE). The amount effects such as pH adjusted at (4, 6, 7, 8, 10 and 12), zinc acetate concentration (0.1, 0.2, 0.3, 0.05, and 0.025 M), reaction temperature (20, 40, 60, 80 and 100 °C), reaction time (20,40, 60, 80, 100, 120, and 140 min), and plant extract volume(1, 2, 3, 4, and 5 mL). The synthesized nanoparticles were characterized by using SEM, TGA/DTA, XRD, UV-Vis, and FT-IR spectroscopic techniques. The SEM analysis revealed that the synthesized ZnO NPs exhibited a rod-shaped morphology, and a total weight loss of 15.29 % observed at 24-544 °C in the TGA/DTA analysis, with no further weight loss above 544 °C, confirmed the high thermal stability of ZnO NPs. The XRD analysis confirmed the formation of small sized ZnO NPs with an average crystal size of 52.9 nm. The UV-Vis analysis revealed the absorption of ZnO NPs at 400 nm, and the characteristic band observed in FT-IR analysis at 635 cm⁻¹ for Zn-O stretching confirmed the formation of ZnO NPs. The biosynthesized ZnO NPs demonstrated a significant in vitro antimicrobial activity as evidenced by the inhibition zone sizes against one Gram-positive <em>S. aureus</em> (17.10 ± 0.17) and two Gram-negative bacteria <em>K. pneumoniae</em> (14.17 ± 0.29), and <em>E. coli(12.83 ± 0.29</em>) at 10 mg/mL using the disc diffusion method. It also showed good antifungal activity against <em>Candida ethanolica (</em>6.90 ± 0.10) and <em>Saccharomyces cerevisiae (</em>6.00 ± 0.10), support the potential of plant-mediated nanoparticle synthesis as a promising route for developing biocompatible antimicrobial agents.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 277-290"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144885854","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}
Patchouli oil residue, a by-product of vacuum distillation, remains underutilized despite its bioactive compound content. This study aimed to characterize the residue using Gas Chromatography–Mass Spectrometry (GC-MS), purify iron (Fe) contamination using activated carbon, evaluate its antimicrobial and antifungal activities, and formulate it into a floor-cleaning soap. GC-MS analysis identified patchouli alcohol (57.19%) as the dominant compound. Purification using 5 g of activated carbon for 3 hours reduced Fe content from 10.351 mg/L to 4.062 mg/L (60.7% reduction), improved residue clarity, and eliminated naphthalene, a potential contaminant. The purified residue exhibited strong antibacterial activity against Staphylococcus aureus (13.28 mm ± 1.38) and moderate activity against Escherichia coli (7.02 mm ± 0.23), as well as strong antifungal activity against Candida albicans (14.88 mm ± 2.88). The formulated floor-cleaning soap met Indonesian National Standard (SNI 1842:2019) for pH, viscosity, specific gravity, foam stability, and homogeneity. It retained bioactivity with inhibition zones of 15.89 mm (S. aureus), 6.00 mm (E. coli), and 10.89 mm (C. albicans), showing enhanced antibacterial activity against S. aureus compared to the purified residue, but slightly lower activity against E. coli and C. albicans. These findings confirm that the formulated product not only meets national standards but also offers antimicrobial functionality. This study contributes a sustainable and scientific approach to valorizing agro-industrial waste into a value-added floor-cleaning product with confirmed antimicrobial and antifungal efficacy, aligning with green chemistry and circular economy principles.
{"title":"Chemical characterization and antimicrobial potential of purified aceh patchouli oil (Pogostemon cablin Benth.) residue for floor cleaning product innovation","authors":"Syaifullah Muhammad , Nadia Isnaini , Binawati Ginting , Hanifa Rifdah Aiman , Ernawati , Vicky Prajaputra , Elly Sufriadi","doi":"10.1016/j.sajce.2025.08.010","DOIUrl":"10.1016/j.sajce.2025.08.010","url":null,"abstract":"<div><div>Patchouli oil residue, a by-product of vacuum distillation, remains underutilized despite its bioactive compound content. This study aimed to characterize the residue using Gas Chromatography–Mass Spectrometry (GC-MS), purify iron (Fe) contamination using activated carbon, evaluate its antimicrobial and antifungal activities, and formulate it into a floor-cleaning soap. GC-MS analysis identified patchouli alcohol (57.19%) as the dominant compound. Purification using 5 g of activated carbon for 3 hours reduced Fe content from 10.351 mg/L to 4.062 mg/L (60.7% reduction), improved residue clarity, and eliminated naphthalene, a potential contaminant. The purified residue exhibited strong antibacterial activity against <em>Staphylococcus aureus</em> (13.28 mm ± 1.38) and moderate activity against <em>Escherichia coli</em> (7.02 mm ± 0.23), as well as strong antifungal activity against <em>Candida albicans</em> (14.88 mm ± 2.88). The formulated floor-cleaning soap met Indonesian National Standard (SNI 1842:2019) for pH, viscosity, specific gravity, foam stability, and homogeneity. It retained bioactivity with inhibition zones of 15.89 mm (<em>S. aureus</em>), 6.00 mm (<em>E. coli</em>), and 10.89 mm (<em>C. albicans</em>), showing enhanced antibacterial activity against <em>S. aureus</em> compared to the purified residue, but slightly lower activity against <em>E. coli</em> and <em>C. albicans</em>. These findings confirm that the formulated product not only meets national standards but also offers antimicrobial functionality. This study contributes a sustainable and scientific approach to valorizing agro-industrial waste into a value-added floor-cleaning product with confirmed antimicrobial and antifungal efficacy, aligning with green chemistry and circular economy principles.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 335-347"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903068","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 : 2025-08-16DOI: 10.1016/j.sajce.2025.08.008
Mehdi Sedaghat, Farshad Farahbod
Sour gas, a natural gas laden with significant quantities of the highly toxic and corrosive hydrogen sulfide (H2S), presents substantial environmental and economic challenges due to its sulfur content. This study explores the potential of nanotechnology to enhance hydrogen sulfide removal from sour gas. The corrosive nature of sulfur compounds necessitates substantial investments in equipment maintenance and protection, particularly within gas pipelines and storage facilities. The removal or reduction of sulfur compounds, including H2S, associated with oil and gas operations offers significant economic, environmental, and health benefits. A hybrid adsorption and magnetic field approach was employed to capture H2S from natural sour gas. The application of a magnetic field elevated the operating temperature, influencing the mobility of carbon nanotubes within the nanofluid and the nanofluid layer. Consequently, a current of 1.5 amperes resulted in a 4.8 % increase in mass transfer coefficient and a 3.6 % increase in mass flow rate. Based on the results of the analysis of variance (ANOVA), as well as the comparison of predicted and experimental data and residual plots, the degree of validity of the predicted model is considered satisfactory. This research demonstrates that the R² coefficient is 0.9972 and the Adjusted R² coefficient is 0.9948.
{"title":"Removal of sulfur compounds from sour gas using metal nano-absorbents: Process optimization","authors":"Mehdi Sedaghat, Farshad Farahbod","doi":"10.1016/j.sajce.2025.08.008","DOIUrl":"10.1016/j.sajce.2025.08.008","url":null,"abstract":"<div><div>Sour gas, a natural gas laden with significant quantities of the highly toxic and corrosive hydrogen sulfide (H2S), presents substantial environmental and economic challenges due to its sulfur content. This study explores the potential of nanotechnology to enhance hydrogen sulfide removal from sour gas. The corrosive nature of sulfur compounds necessitates substantial investments in equipment maintenance and protection, particularly within gas pipelines and storage facilities. The removal or reduction of sulfur compounds, including H2S, associated with oil and gas operations offers significant economic, environmental, and health benefits. A hybrid adsorption and magnetic field approach was employed to capture H2S from natural sour gas. The application of a magnetic field elevated the operating temperature, influencing the mobility of carbon nanotubes within the nanofluid and the nanofluid layer. Consequently, a current of 1.5 amperes resulted in a 4.8 % increase in mass transfer coefficient and a 3.6 % increase in mass flow rate. Based on the results of the analysis of variance (ANOVA), as well as the comparison of predicted and experimental data and residual plots, the degree of validity of the predicted model is considered satisfactory. This research demonstrates that the R² coefficient is 0.9972 and the Adjusted R² coefficient is 0.9948.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"54 ","pages":"Pages 266-276"},"PeriodicalIF":0.0,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865147","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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