South African Journal of Chemical Engineering最新文献_第3页

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 用芦荟提取物处理刚果红污染水，水热法制备纳米晶Mn-Zn铁氧体并进行表征

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-11-16 DOI: 10.1016/j.sajce.2025.11.010

Melissa Quevedo Lopez , Fernanda Pilaquinga , Alexis Debut , Alberto Albis Arrieta , Andrés Rosales Rivera , Zulia Caamaño De Avila

Nanocrystalline ferrites of the Mn_1-xZn_xFe₂O₄ 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.

以芦荟提取物为吸附剂，采用水热法合成了Mn - xznxfe2o4体系（x = 0、0.2、0.4、0.6、0.8和1.0）的纳米晶铁氧体，并对偶氮有机染料（刚果红）污染的水进行了处理。采用SEM、XRD、FTIR、VSM、UV-Vis、DLS和TGA等技术对所得纳米铁素体进行了形貌、磁性、光学和热表征。XRD分析得到尖晶石型结构的纳米铁氧体，晶粒尺寸为19.5 ~ 42.1 nm。扫描电镜形态分析显示，不规则形状的颗粒团块具有纳米大小。磁滞曲线显示了铁氧体的磁软特性，饱和磁化强度Ms在37.89 ~ 8.78 emu/g之间，随Zn含量的增加而减小。紫外可见光谱证实铁氧体主要在紫外区吸收，带隙能量随Zn的加入而增加。对刚果红染料的吸附试验表明，锰锌铁氧体具有良好的吸附剂性能。在所有组合物中，x = 0.0的铁氧体在不同浓度（25 ppm）和接触时间（20 min）下的去除率为73.65%。同样，当x = 0.0时，该铁氧体在pH为5时对刚果红的吸收率达到84%。同时，当x = 1.0时，铁素体在pH = 7时的去除率为74.84%。这些结果证明，由芦荟提取物合成的锰锌铁氧体是一种可持续和有效的处理被刚果红染料污染的水的替代品。

{"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":"2026-01-01","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}

引用次数: 0

Process design for the continuous production of α- and γ-mangostin from mangosteen pericarp with integrated solvent recovery 以山竹果皮为原料连续生产α-和γ-山竹苷的工艺设计

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-12-09 DOI: 10.1016/j.sajce.2025.12.008

Preuk Tangpromphan , Amaraporn Kaewchada , Attasak Jaree

Mangosteen pericarp, a major agricultural by-product, is a rich source of xanthones, including α- and γ-mangostin, which possess significant anticancer and anti-inflammatory properties. This study details the continuous production process for these bioactive compounds, focusing on material and energy balance, performance parameters, and preliminary economic feasibility. The process includes material pretreatment, extraction, and separation using a three-zone simulated moving bed (TZ-SMB) system.

Extraction experiments were optimized to model the yield of α-mangostin based on temperature and solvent (acetonitrile) concentration. The optimal extraction conditions were found to be 40 °C and 65 % v/v acetonitrile, achieving a maximum yield of 70.49 mg/g of dried pericarp. For the separation process, models based on triangle theory were developed to determine the maximum feed flow rate for the TZ-SMB system while ensuring at least 98 % relative purity for both compounds.

A block flow diagram was used for material and energy balance calculations, performed in MATLAB. The wet mangosteen pericarp feed rate was varied to achieve the target xanthone concentrations required for the TZ-SMB design. At the optimal solvent recycle ratio of 90 %, the system demonstrated a daily production capacity of 477.65 mg for α-mangostin and 140.76 mg for γ-mangostin, with a favorable benefit-to-cost ratio. The economic analysis confirms the process's profitability, especially with solvent recovery. This work provides a foundational preliminary design, supporting strategic decision-making and laying the groundwork for more detailed process design using simulation software.

山竹果皮是一种重要的农业副产品，含有丰富的山酮，包括α-和γ-山竹苷，具有显著的抗癌和抗炎作用。本研究详细介绍了这些生物活性化合物的连续生产过程，重点关注物质和能量平衡、性能参数和初步的经济可行性。该过程包括使用三区模拟移动床（TZ-SMB）系统进行材料预处理、提取和分离。以提取温度和溶剂（乙腈）浓度为参数，对α-山竹苷提取率进行优化。最佳提取条件为40°C、65% v/v乙腈，最大得率为70.49 mg/g。对于分离过程，建立了基于三角理论的模型，以确定TZ-SMB系统的最大进料流量，同时确保两种化合物的相对纯度至少为98%。在MATLAB中使用块流程图进行物质和能量平衡计算。通过改变湿山竹果皮的进料速率来达到z - smb设计所需的靶山酮浓度。在溶剂回收率为90%的条件下，该体系日产量分别为477.65 mg α-山竹苷和140.76 mg γ-山竹苷，具有较好的经济效益。经济分析证实了该工艺的盈利能力，特别是溶剂回收。这项工作提供了一个基本的初步设计，支持战略决策，并为使用仿真软件进行更详细的工艺设计奠定了基础。

{"title":"Process design for the continuous production of α- and γ-mangostin from mangosteen pericarp with integrated solvent recovery","authors":"Preuk Tangpromphan , Amaraporn Kaewchada , Attasak Jaree","doi":"10.1016/j.sajce.2025.12.008","DOIUrl":"10.1016/j.sajce.2025.12.008","url":null,"abstract":"<div><div>Mangosteen pericarp, a major agricultural by-product, is a rich source of xanthones, including α- and γ-mangostin, which possess significant anticancer and anti-inflammatory properties. This study details the continuous production process for these bioactive compounds, focusing on material and energy balance, performance parameters, and preliminary economic feasibility. The process includes material pretreatment, extraction, and separation using a three-zone simulated moving bed (TZ-SMB) system.</div><div>Extraction experiments were optimized to model the yield of α-mangostin based on temperature and solvent (acetonitrile) concentration. The optimal extraction conditions were found to be 40 °C and 65 % v/v acetonitrile, achieving a maximum yield of 70.49 mg/g of dried pericarp. For the separation process, models based on triangle theory were developed to determine the maximum feed flow rate for the TZ-SMB system while ensuring at least 98 % relative purity for both compounds.</div><div>A block flow diagram was used for material and energy balance calculations, performed in MATLAB. The wet mangosteen pericarp feed rate was varied to achieve the target xanthone concentrations required for the TZ-SMB design. At the optimal solvent recycle ratio of 90 %, the system demonstrated a daily production capacity of 477.65 mg for α-mangostin and 140.76 mg for γ-mangostin, with a favorable benefit-to-cost ratio. The economic analysis confirms the process's profitability, especially with solvent recovery. This work provides a foundational preliminary design, supporting strategic decision-making and laying the groundwork for more detailed process design using simulation software.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 460-474"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development and analysis of PVC glass slides for urine microstructure studies 尿液微结构研究用PVC玻片的研制与分析

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-12-30 DOI: 10.1016/j.sajce.2025.12.018

Mohammed Alwan Farhan, Luma Salman Abd, Zaid H. Mahmoud

The long-term maintenance of urine precipitation microstructures stays a main restriction in medical laboratory education and routine urinalysis, as traditional glass sides typically permit sample stability for only 1–3 h. In this work, a novel polyvinyl chloride (PVC)-coated glass slide system was advanced to capable long-term stabilization and microscopic conception of urine precipitation components. PVC films were functionalized with p-chlorobenzamidine (L) as photostabilizer to inhibit photodegradation induced via elongate exposure to UV light and microscope. The films photostability were systematically investigated employing FTIR, viscosity measurements, UV–Vis and FESEM analysis. At 365 nm, after 125 h of UV irradiation, the carbonyl index (Ico) for PVC+L films were increased to 0.13, compared with 0.18 of PVC, suggesting an essential reduction in oxidative degradation. The constant rate of photodegradation (kd) was reduced from 0.0021 s^-1 for pristine PVC to 0.0014 s^-1 for PVC+L sample, while the quantum yield of main-chain scission (Φcs) was decreased from 373×10¹³ to 884×10¹². Moreover, the PVC+L films preserved a higher viscosity-average molecular weight (Mv 260,000) contracted with the pristine PVC film after protracted irradiation, suggesting efficient inhibition of PVC chain scission. Functionally, at 295 nm, the PVC+L films appeared high (90 % transmittance) and cement clear microscopic conception of urine precipitation components. Cystine crystals, uric acid, calcium oxalate and triple phosphate, as well as amorphous materials, epithelial cells, kept optically distinguishable and morphologically intact for up to one year. These finds illustrate, for the first time, that photostabilized films can use as transparent, durable and chemically stable substrates for urine precipitation preservation, giving a low-cost and practical platform for routine microscopy, medical laboratory training and educational characteristics.

尿沉淀微观结构的长期维持一直是医学实验室教育和常规尿液分析的主要限制，因为传统的玻璃侧通常只允许样品稳定1-3小时。在这项工作中，一种新型聚氯乙烯（PVC）涂层玻璃载玻片系统被推进到能够长期稳定和尿液沉淀成分的微观概念。以对氯苯脒(L)为光稳定剂，对聚氯乙烯（PVC）薄膜进行了长时间紫外曝光和显微镜曝光，抑制了聚氯乙烯薄膜的光降解。采用红外光谱（FTIR）、粘度测试、紫外可见光谱（UV-Vis）和FESEM分析等方法对膜的光稳定性进行了系统的研究。在365 nm处，经过125 h的紫外照射，PVC+L薄膜的羰基指数（Ico）增加到0.13，而PVC的为0.18，表明氧化降解明显减少。恒定光降解速率（kd）从原始PVC的0.0021 s-1降低到PVC+L样品的0.0014 s-1，而主链断裂量子产率（Φcs）从373×1013降低到884×1012。此外，PVC+L膜在长时间辐照后保持了较高的粘度-平均分子量（Mv 26万）与原始PVC膜相比，表明有效抑制了PVC链断裂。在功能上，在295 nm处，PVC+L膜表现出较高的透光率（90%），并且水泥清晰的尿液沉淀成分的微观概念。胱氨酸晶体，尿酸，草酸钙和三磷酸，以及无定形材料，上皮细胞，保持光学可区分和形态完整长达一年。这些发现首次表明，光稳定膜可以作为透明、耐用和化学稳定的基底来保存尿液沉淀，为常规显微镜、医学实验室培训和教育提供了一个低成本和实用的平台。

{"title":"Development and analysis of PVC glass slides for urine microstructure studies","authors":"Mohammed Alwan Farhan, Luma Salman Abd, Zaid H. Mahmoud","doi":"10.1016/j.sajce.2025.12.018","DOIUrl":"10.1016/j.sajce.2025.12.018","url":null,"abstract":"<div><div>The long-term maintenance of urine precipitation microstructures stays a main restriction in medical laboratory education and routine urinalysis, as traditional glass sides typically permit sample stability for only 1–3 h. In this work, a novel polyvinyl chloride (PVC)-coated glass slide system was advanced to capable long-term stabilization and microscopic conception of urine precipitation components. PVC films were functionalized with p-chlorobenzamidine (L) as photostabilizer to inhibit photodegradation induced via elongate exposure to UV light and microscope. The films photostability were systematically investigated employing FTIR, viscosity measurements, UV–Vis and FESEM analysis. At 365 nm, after 125 h of UV irradiation, the carbonyl index (Ico) for PVC+<em>L</em> films were increased to 0.13, compared with 0.18 of PVC, suggesting an essential reduction in oxidative degradation. The constant rate of photodegradation (kd) was reduced from 0.0021 s<sup>-1</sup> for pristine PVC to 0.0014 s<sup>-1</sup> for PVC+<em>L</em> sample, while the quantum yield of main-chain scission (Φcs) was decreased from 373×10<sup>13</sup> to 884×10<sup>12</sup>. Moreover, the PVC+<em>L</em> films preserved a higher viscosity-average molecular weight (Mv 260,000) contracted with the pristine PVC film after protracted irradiation, suggesting efficient inhibition of PVC chain scission. Functionally, at 295 nm, the PVC+<em>L</em> films appeared high (90 % transmittance) and cement clear microscopic conception of urine precipitation components. Cystine crystals, uric acid, calcium oxalate and triple phosphate, as well as amorphous materials, epithelial cells, kept optically distinguishable and morphologically intact for up to one year. These finds illustrate, for the first time, that photostabilized films can use as transparent, durable and chemically stable substrates for urine precipitation preservation, giving a low-cost and practical platform for routine microscopy, medical laboratory training and educational characteristics.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 575-585"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145924178","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}

引用次数: 0

Evaluation of combination tanning as a sustainable alternative to chrome tanning for shoe upper leather production 评价复合鞣法作为可持续替代铬鞣法的鞋面革生产

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-11-13 DOI: 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.

铬鞣虽然效率高，但由于有毒铬的排放对环境造成了严重污染，威胁着水、土壤和生态系统，因此突出了对可持续鞣制替代品的需求。植物鞣制是一种天然的选择，但它通常生产的皮革具有较低的机械强度和耐热性，限制了其在苛刻应用中的使用。本研究探索以植物单宁为主要鞣制剂，再以醛、铝盐、植物单宁和钛盐复鞣的环保复合鞣制方法，以生产出对环境影响最小的高品质鞋面革。与全植物鞣革相比，复合鞣革表现出优越的机械性能，抗拉强度为260 - 275公斤/平方厘米，伸长率为41 - 47%，缝线撕裂强度为119 - 155公斤/厘米，舌撕裂强度为55公斤/厘米，粘合强度为590 - 630克/厘米，颗粒裂纹载荷为29公斤，膨胀率为8.8毫米。收缩温度也有所提高，证实了热稳定性的增强。染色牢度和水蒸气渗透性略有下降，这是由于胶原蛋白结构紧密和无机复鞣剂减少了染料固定。扫描电镜分析显示，醛盐、铝盐和钛盐对纤维排列、密度和表面光滑度的改善。复鞣废水的环境评价结果显示，与单独进行植物鞣相比，复鞣废水的BOD、COD、TDS和TSS均较低，表明复鞣剂效率提高，有机负荷降低。总的来说，复合鞣制方法生产的鞋面皮革具有理想的强度，热稳定性和环境兼容性，提供了铬鞣制的可持续替代方案。

{"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":"2026-01-01","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}

引用次数: 0

Thermal management of micropolar ferrofluid forced convective flow in a T-shaped vented chamber via a proportional-integral-derivative controller 用比例-积分-导数控制器对t型通风腔内微极铁磁流体强制对流的热管理

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-11-17 DOI: 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 ≤ K_p ≤ 0.20 m/sK, 0.005 ≤ K_i ≤ 0.01 m/s² K, and 0.0005 ≤ K_d ≤ 0.05 m/K) to achieve optimal response characteristics. The discoveries sensibly demonstrate that K_p = 0.06 m/sK, K_i = 0.01 m/s² K, and K_d = 0.05 m/K are the optimum settings for the selected flow controller’s gains.

本研究采用比例-积分-导数流动控制器对强制对流条件下的二维t型通风室进行调节，旨在提高其水热性能。在复杂的结构中，热量提取必须根据波动的流入条件动态调整，因此保持有效的温度调节对于一些应用至关重要，例如紧凑型冷却系统、电子元件冷却和储能单元。在这种情况下，微极铁磁流体（fe3o4 -水）在通风室中循环，在固定室温下从左侧进口口进入，在环境条件下从右侧出口口离开。底部表面被加热，而室的顶部表面保持冷。根据连续流量控制器的反馈来调节流入速度。在系统出口设置边界温度探头，频繁测量铁磁流体温度，并向流量控制器发送反馈响应。使用Galerkin有限元技术解决了代表微极铁磁流体流动和热输运的控制质量、动量和能量方程，允许对系统行为进行全面的计算分析。控制器的性能是根据上升时间、超调百分比和相对于期望的设定点热条件的稳定时间来评估的。随后，对所选流量控制器（比例增益、积分增益和导数增益）在其工作范围（0.06≤Kp≤0.20 m/sK、0.005≤Ki≤0.01 m/s2 K、0.0005≤Kd≤0.05 m/K）内进行参数化仿真，以获得最佳响应特性。结果表明，Kp = 0.06 m/sK, Ki = 0.01 m/s2 K, Kd = 0.05 m/K是所选流量控制器增益的最佳设置。

{"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":"2026-01-01","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}

引用次数: 0

Investigation of the two-way movement of Williamson micropolar fluid in a porous medium with consideration of activation energy and thermal radiation 考虑活化能和热辐射的微极流体在多孔介质中的双向运动研究

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-11-20 DOI: 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.

威廉姆森流体在拉伸薄片上的流动可以作为各种现实世界场景的模型，这些场景涉及非牛顿流体与运动表面的相互作用。其显著的实际应用是在聚合物加工、食品加工和生物医学应用领域。该模型的主要目标是研究欧姆加热和粘性耗散对多孔介质中Williamson流体和微极流体在延伸表面上双向流动的影响。本研究的新颖之处在于首次采用有限元方法对平面上不可压缩对流流动的流体和热特性进行数值分析。这项工作的另一个新颖方面是对运动流体流动中的阿累尼乌斯函数项和磁力的研究。对地表的热对流和速度滑移也进行了研究。该问题的数学模型通过适当的变量组合得到高阶非线性常微分方程。用有限元法求解给定的非线性微分方程组。目前的研究揭示了一些重要的见解，特别是表面摩擦随着孔隙度的增加而增加，以及Williamson流体和微极性流体的特征。通过检查和绘制分析产生的各种组件来分析和可视化流模式。随着滑移参数的增大，速度场在x方向上减小。当k = 3时，流动在被拉伸薄板上的Williamson流体的换热量增加，在最低换热条件下，其速度比k = 1时大约大45.55%。x方向的速度随滑移参数的增大而减小。此外，还观察到随着Eckert数值的增加，Williamson流体的浓度降低，而温度分布增加。

{"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":"2026-01-01","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}

引用次数: 0

Influence of silica addition in magnetite (Fe3O4) particles on physical properties for the application of nano-lubricant 磁铁矿（Fe3O4）颗粒中添加二氧化硅对纳米润滑剂物理性能的影响

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-11-17 DOI: 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.

成功地制备了二氧化硅包覆的纳米磁铁矿作为润滑剂添加剂。该材料采用共沉淀法和超声法相结合的方法制备。在本研究中，还进行了SEM表征来支持形态分析，XRD分析来确定晶体性质，FTIR分析来帮助确定官能团。基于这些表征，二氧化硅成功地包覆了磁铁矿。然后，进行原子吸收光谱测试、粘度测试和润滑剂测试，以评估在润滑剂中添加二氧化硅包覆磁铁矿的影响。使用磁铁矿的润滑剂，无论是否添加TEOS，在粘度为100°C时，润滑剂和纳米润滑剂的稳定性分别为8.65 mm²/s和8.96 mm²/s。在润滑油和纳米润滑油中，总碱基值均为0.55，得到了污染结果。综上所述，添加剂可以制备出合适的纳米润滑剂。

{"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":"2026-01-01","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}

引用次数: 0

Photoelectrocatalytic degradation of tetracycline by a novel Gr /Ni-Sb-SnO2 photo-anode 新型Gr /Ni-Sb-SnO2光阳极对四环素的光电催化降解

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-10-22 DOI: 10.1016/j.sajce.2025.10.004

Heba F. Uonis, Ali H. Abbar

The widespread use of pharmaceutical products in pharmaceutical therapies and agriculture has led to environmental pollution worldwide. In this work, a photoelectrocatalytic (PEC) process was applied for the degradation of a typical pharmaceutical product, tetracycline (TC), via a novel graphite (Gr)/Ni-Sb-SnO₂ photo-anode. The effect of nickel doping on the catalytic activity of the photo-anode was investigated with the help of XRD, SEM, AFM, and LSV techniques. The influence of several PEC parameters such as current density, pH, and initial concentration on the degradation of TC was studied and optimized using a response surface methodology (RSM). It was found that the Gr/Ni-Sb-SnO₂ (1:5:95) is the best photo-anode for TC degradation, and that increasing the nickel content above 1 % has a negative effect on the Gr/Ni-Sb-SnO₂ efficiency. RSM was found to be effective in describing the mathematical model linking PEC variables with TC removal at a correlation coefficient of 98.89 %. A significant interaction between the variables was observed in PEC, with the square term contributing 64.94 % to the model, and current density was the most important factor affecting TC degradation. The optimal conditions were a current density of 4.6 mA/cm², pH of 4.36, an initial concentration of 43 mg/L, and a time of 150 min in which a TC removal rate of 83.7 % was achieved corresponding to a COD removal of 62.3 % at a total energy consumption of 64.46 kWh/m³. A significant synergistic effect of PEC was observed, with rate constant being 1.56 times higher than that obtained for the photocatalytic process alone. In addition, the Gr/Ni-Sb-SnO₂ (1:5:95) photo-anode exhibited excellent degradation stability after five cycles of degradation test. Hence, Gr/Ni-Sb-SnO₂ (1:5:95) may serve as a good photo-anode for the photoelectrochemical treatment of industrial wastewaters.

医药产品在医药治疗和农业中的广泛使用导致了世界范围内的环境污染。在这项工作中，应用光电催化（PEC）工艺通过新型石墨(Gr)/Ni-Sb-SnO2光阳极降解典型的药物产品四环素（TC）。利用XRD、SEM、AFM和LSV等技术研究了镍掺杂对光阳极催化活性的影响。采用响应面法（RSM）研究了电流密度、pH和初始浓度等多个PEC参数对TC降解的影响，并进行了优化。结果表明，Gr/Ni-Sb-SnO2（1:5:95）是TC降解的最佳光阳极，镍含量增加1%以上会对Gr/Ni-Sb-SnO2效率产生负面影响。RSM可以有效地描述PEC变量与TC去除之间的数学模型，相关系数为98.89%。在PEC中，变量之间存在显著的交互作用，平方项对模型的贡献率为64.94%，电流密度是影响TC降解的最重要因素。最佳条件为电流密度4.6 mA/cm²，pH为4.36，初始浓度为43 mg/L，时间为150 min，总能耗为64.46 kWh/m3， TC去除率为83.7%，COD去除率为62.3%。PEC具有显著的协同效应，其速率常数比单独光催化的速率常数高1.56倍。此外，经过5次循环降解试验，Gr/Ni-Sb-SnO2（1:5:95）光阳极表现出优异的降解稳定性。因此，Gr/Ni-Sb-SnO2（1:5:95）可以作为一种良好的光阳极用于工业废水的光电化学处理。

{"title":"Photoelectrocatalytic degradation of tetracycline by a novel Gr /Ni-Sb-SnO2 photo-anode","authors":"Heba F. Uonis, Ali H. Abbar","doi":"10.1016/j.sajce.2025.10.004","DOIUrl":"10.1016/j.sajce.2025.10.004","url":null,"abstract":"<div><div>The widespread use of pharmaceutical products in pharmaceutical therapies and agriculture has led to environmental pollution worldwide. In this work, a photoelectrocatalytic (PEC) process was applied for the degradation of a typical pharmaceutical product, tetracycline (TC), via a novel graphite (Gr)/Ni-Sb-SnO<sub>2</sub> photo-anode. The effect of nickel doping on the catalytic activity of the photo-anode was investigated with the help of XRD, SEM, AFM, and LSV techniques. The influence of several PEC parameters such as current density, pH, and initial concentration on the degradation of TC was studied and optimized using a response surface methodology (RSM). It was found that the Gr/Ni-Sb-SnO<sub>2</sub> (1:5:95) is the best photo-anode for TC degradation, and that increasing the nickel content above 1 % has a negative effect on the Gr/Ni-Sb-SnO<sub>2</sub> efficiency. RSM was found to be effective in describing the mathematical model linking PEC variables with TC removal at a correlation coefficient of 98.89 %. A significant interaction between the variables was observed in PEC, with the square term contributing 64.94 % to the model, and current density was the most important factor affecting TC degradation. The optimal conditions were a current density of 4.6 mA/cm², pH of 4.36, an initial concentration of 43 mg/L, and a time of 150 min in which a TC removal rate of 83.7 % was achieved corresponding to a COD removal of 62.3 % at a total energy consumption of 64.46 kWh/m<sup>3</sup>. A significant synergistic effect of PEC was observed, with rate constant being 1.56 times higher than that obtained for the photocatalytic process alone. In addition, the Gr/Ni-Sb-SnO<sub>2</sub> (1:5:95) photo-anode exhibited excellent degradation stability after five cycles of degradation test. Hence, Gr/Ni-Sb-SnO<sub>2</sub> (1:5:95) may serve as a good photo-anode for the photoelectrochemical treatment of industrial wastewaters.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 24-39"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145366028","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}

引用次数: 0

Novel carbon-based photocatalysts for degradation of micropollutants 新型碳基光催化剂降解微污染物

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-12-03 DOI: 10.1016/j.sajce.2025.12.001

Neha Rajpal , Esther Naidoo , Ebrahim Kadwa , Sinethemba Xabela , Martina Dlasková , Olga Šolcová , Karel Soukup , Milan Carsky , David Lokhat

In this study, novel TiO₂ doped photocatalysts based on carbon foam derived from Typha capensis, a sustainable and naturally abundant biomass source, were prepared and evaluated for removal of an organic dye. The carbon foam was produced through a unique two-step process involving baking and carbonization, followed by chemical activation using either NaOH or HCl to improve its surface area, porosity, and surface chemistry. TiO₂ was then immobilised onto the activated carbon foam using a sol-gel method to enhance photocatalytic activity. The materials were extensively characterised, with BET surface area analysis showing a significant increase after chemical activation. The base-activated foam demonstrated the highest surface area. Microscopic analysis revealed a porous foam structure and confirmed the even distribution of TiO₂ particles on the carbon surface. X-ray diffraction analysis verified the presence of the anatase phase of TiO₂, which is known for its superior photocatalytic activity. Photocatalytic tests showed that the acid-activated carbon foam doped with TiO₂ exhibited the best performance, achieving a Rhodamine B degradation efficiency of approximately 19% under UV light. The superior activity is believed to stem from the improved surface chemistry introduced by acid activation, which aids TiO₂ dispersion and interaction with the pollutant molecules. This study highlights the potential of the novel carbon foam as a sustainable, low-cost, and potentially effective photocatalyst support for water treatment.

在本研究中，我们制备了一种新型TiO2掺杂光催化剂，该催化剂基于来自自然丰富的可持续生物质资源Typha capensis的碳泡沫，并对其去除有机染料进行了评估。碳泡沫通过烘烤和碳化两步工艺生产，然后使用NaOH或HCl进行化学活化，以改善其表面积、孔隙率和表面化学性质。然后采用溶胶-凝胶法将TiO2固定在活性炭泡沫上，以增强光催化活性。材料被广泛表征，BET表面积分析显示化学活化后显着增加。基活化泡沫的表面积最大。微观分析显示出多孔泡沫结构，并证实了TiO2颗粒在碳表面的均匀分布。x射线衍射分析证实了TiO2中锐钛矿相的存在，锐钛矿以其优异的光催化活性而闻名。光催化实验表明，掺杂TiO2的酸性活性炭泡沫表现出最好的性能，在紫外光下对罗丹明B的降解效率约为19%。优异的活性被认为源于酸活化引入的表面化学改善，这有助于TiO2的分散和与污染物分子的相互作用。这项研究强调了新型碳泡沫作为一种可持续的、低成本的、潜在有效的水处理光催化剂的潜力。

{"title":"Novel carbon-based photocatalysts for degradation of micropollutants","authors":"Neha Rajpal , Esther Naidoo , Ebrahim Kadwa , Sinethemba Xabela , Martina Dlasková , Olga Šolcová , Karel Soukup , Milan Carsky , David Lokhat","doi":"10.1016/j.sajce.2025.12.001","DOIUrl":"10.1016/j.sajce.2025.12.001","url":null,"abstract":"<div><div>In this study, novel TiO<sub>2</sub> doped photocatalysts based on carbon foam derived from <em>Typha capensis</em>, a sustainable and naturally abundant biomass source, were prepared and evaluated for removal of an organic dye. The carbon foam was produced through a unique two-step process involving baking and carbonization, followed by chemical activation using either NaOH or HCl to improve its surface area, porosity, and surface chemistry. TiO<sub>2</sub> was then immobilised onto the activated carbon foam using a sol-gel method to enhance photocatalytic activity. The materials were extensively characterised, with BET surface area analysis showing a significant increase after chemical activation. The base-activated foam demonstrated the highest surface area. Microscopic analysis revealed a porous foam structure and confirmed the even distribution of TiO<sub>2</sub> particles on the carbon surface. X-ray diffraction analysis verified the presence of the anatase phase of TiO<sub>2</sub>, which is known for its superior photocatalytic activity. Photocatalytic tests showed that the acid-activated carbon foam doped with TiO<sub>2</sub> exhibited the best performance, achieving a Rhodamine B degradation efficiency of approximately 19% under UV light. The superior activity is believed to stem from the improved surface chemistry introduced by acid activation, which aids TiO<sub>2</sub> dispersion and interaction with the pollutant molecules. This study highlights the potential of the novel carbon foam as a sustainable, low-cost, and potentially effective photocatalyst support for water treatment.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 358-367"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of carbon sources and biosurfactants on selenite and lead bioremediation by Enterococcus sp 碳源和生物表面活性剂对肠球菌修复亚硒酸盐和铅的影响

Q1 Social Sciences

South African Journal of Chemical Engineering

Pub Date : 2026-01-01 Epub Date: 2025-10-30 DOI: 10.1016/j.sajce.2025.10.008

Job T. Tendenedzai, Evans M.N. Chirwa, Hendrik G. Brink

This study explored Enterococcus sp.'s potential for bioremediating selenite (SeO₃²⁻) and lead (Pb²⁺) contamination using different carbon sources (glucose, cooking oil and crude oil) while elucidating the underlying mechanisms. Aerobic batch reduction experiments were conducted (35±2 °C, 120 rpm, pH≈8, 50 h) with an initial 1 mM concentration of either SeO₃²⁻or Pb²⁺ which was quantified by Ion Chromatography and Atomic Absorption Spectroscopy respectively. Key results showed that carbon source selection significantly influenced SeO₃²⁻and Pb²⁺ removal rates, elemental selenium (Se⁰) formation, and protein synthesis. Glucose and cooking oil were found to be the most efficient, leading to rapid SeO₃²⁻reduction (58 % and 55 % reduction, respectively), compared to crude oil (39 %). Similarly, Pb²⁺ removal rates followed a similar trend, with 38 %, 33 %, and 25 % reduction using glucose, cooking oil, and crude oil, respectively. The study also highlighted Enterococcus sp.'s varied mechanisms for SeO₃²⁻and Pb²⁺ reduction, with SeO₃²⁻ precipitating to Se⁰ while no precipitation of Pb²⁺ to Pb⁰ was observed. Furthermore, the bacteria exhibited versatility in biosurfactant production across the various carbon substrates. The biosurfactants notably promoted Se⁰ precipitation thus shedding light on their potential role in metal ion bioreduction.

本研究探讨了肠球菌利用不同碳源（葡萄糖、食用油和原油）对亚硒酸盐（SeO32−）和铅（Pb2+）污染进行生物修复的潜力，并阐明了其潜在机制。在35±2℃，120 rpm, pH≈8,50 h的条件下，采用离子色谱法和原子吸收光谱法分别对初始浓度为1 mM的SeO32−或Pb2+进行好氧批量还原实验。关键结果表明，碳源选择显著影响SeO32−和Pb2+去除率、元素硒（Se0）形成和蛋白质合成。葡萄糖和食用油被发现是最有效的，导致SeO32−的快速还原（分别减少58%和55%），而原油（39%）。同样，Pb2+的去除率也有类似的趋势，葡萄糖、食用油和原油的去除率分别为38%、33%和25%。研究还强调了Enterococcus sp.还原SeO32−和Pb2+的不同机制，其中SeO32−沉淀为Se0，而Pb2+没有沉淀为Pb0。此外，该细菌在各种碳底物上表现出生物表面活性剂生产的多功能性。这些生物表面活性剂显著促进了Se0的沉淀，从而揭示了它们在金属离子生物还原中的潜在作用。

{"title":"Influence of carbon sources and biosurfactants on selenite and lead bioremediation by Enterococcus sp","authors":"Job T. Tendenedzai, Evans M.N. Chirwa, Hendrik G. Brink","doi":"10.1016/j.sajce.2025.10.008","DOIUrl":"10.1016/j.sajce.2025.10.008","url":null,"abstract":"<div><div>This study explored <em>Enterococcus</em> sp.'s potential for bioremediating selenite (SeO<sub>3</sub><sup>2−</sup>) and lead (Pb<sup>2+</sup>) contamination using different carbon sources (glucose, cooking oil and crude oil) while elucidating the underlying mechanisms. Aerobic batch reduction experiments were conducted (35±2 °C, 120 rpm, pH≈8, 50 h) with an initial 1 mM concentration of either SeO<sub>3</sub><sup>2−</sup>or Pb<sup>2+</sup> which was quantified by Ion Chromatography and Atomic Absorption Spectroscopy respectively. Key results showed that carbon source selection significantly influenced SeO<sub>3</sub><sup>2−</sup>and Pb<sup>2+</sup> removal rates, elemental selenium (Se<sup>0</sup>) formation, and protein synthesis. Glucose and cooking oil were found to be the most efficient, leading to rapid SeO<sub>3</sub><sup>2−</sup>reduction (58 % and 55 % reduction, respectively), compared to crude oil (39 %). Similarly, Pb<sup>2+</sup> removal rates followed a similar trend, with 38 %, 33 %, and 25 % reduction using glucose, cooking oil, and crude oil, respectively. The study also highlighted <em>Enterococcus</em> sp.'s varied mechanisms for SeO<sub>3</sub><sup>2−</sup>and Pb<sup>2+</sup> reduction, with SeO<sub>3</sub><sup>2−</sup> precipitating to Se<sup>0</sup> while no precipitation of Pb<sup>2+</sup> to Pb<sup>0</sup> was observed. Furthermore, the bacteria exhibited versatility in biosurfactant production across the various carbon substrates. The biosurfactants notably promoted Se<sup>0</sup> precipitation thus shedding light on their potential role in metal ion bioreduction.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"55 ","pages":"Pages 63-71"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145420016","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}

引用次数: 0