Pub Date : 2025-03-28DOI: 10.3390/separations12040078
Yinan Li, Xiangmin Xu, Xiaofeng Fang, Fang Li
Edge-capping modified MXene membranes with new channels created by lateral nanosheets are of great research significance. After introducing tripolyphosphate (STPP) to Ti edges of Ti3C2Tx nanosheets and fabricating the STPP-MXene membranes edge-capping method, this research investigated the performance optimization mechanism of STPP-modified MXene membranes in terms of salt permeability (NaCl, Na2SO4, MgCl2, and MgSO4) and transmembrane energy barriers (Esalt) through the concentration gradient permeation test. Experimental results demonstrated an approximately 1.86-fold enhancement in salt flux (Js) compared to the MXene membranes. The solution–diffusion model was also introduced to evaluate the salt solubility (Ks) and diffusivity (Ds) during permeation. Furthermore, analysis of transmembrane energy barriers revealed that STPP modification induced significantly larger reductions in activation energy for magnesium salts (MgSO4: 55.1%; MgCl2: 47.4%) compared to sodium salts (NaCl: 30.5%; Na2SO4: 30.9%). This phenomenon indicated the weakened electrostatic interactions between high-valent Mg2+ and the modified lateral membrane Ti edges, whereas the limited charge density of Na+ resulted in relatively modest optimization. The results highlight the contribution of STPP capping on the edges of adjacent lateral nanosheets. Therefore, the modification increased the transportation rate of cations across the MXene membrane by more than twice, thus advancing the application of 2D MXene membranes in resource recovery.
{"title":"Ion Transport Mechanism in the Sub-Nano Channels of Edge-Capping Modified Transition Metal Carbides/Nitride Membranes","authors":"Yinan Li, Xiangmin Xu, Xiaofeng Fang, Fang Li","doi":"10.3390/separations12040078","DOIUrl":"https://doi.org/10.3390/separations12040078","url":null,"abstract":"Edge-capping modified MXene membranes with new channels created by lateral nanosheets are of great research significance. After introducing tripolyphosphate (STPP) to Ti edges of Ti3C2Tx nanosheets and fabricating the STPP-MXene membranes edge-capping method, this research investigated the performance optimization mechanism of STPP-modified MXene membranes in terms of salt permeability (NaCl, Na2SO4, MgCl2, and MgSO4) and transmembrane energy barriers (Esalt) through the concentration gradient permeation test. Experimental results demonstrated an approximately 1.86-fold enhancement in salt flux (Js) compared to the MXene membranes. The solution–diffusion model was also introduced to evaluate the salt solubility (Ks) and diffusivity (Ds) during permeation. Furthermore, analysis of transmembrane energy barriers revealed that STPP modification induced significantly larger reductions in activation energy for magnesium salts (MgSO4: 55.1%; MgCl2: 47.4%) compared to sodium salts (NaCl: 30.5%; Na2SO4: 30.9%). This phenomenon indicated the weakened electrostatic interactions between high-valent Mg2+ and the modified lateral membrane Ti edges, whereas the limited charge density of Na+ resulted in relatively modest optimization. The results highlight the contribution of STPP capping on the edges of adjacent lateral nanosheets. Therefore, the modification increased the transportation rate of cations across the MXene membrane by more than twice, thus advancing the application of 2D MXene membranes in resource recovery.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"12 4","pages":"78-78"},"PeriodicalIF":0.0,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2297-8739/12/4/78/pdf?version=1743155969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147332580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Selective separation of hydroxylamine (HA) from metal ions to prepare high-purity HA remains a challenge. In this study, given that HA can react with carbonyl compounds, TTA (thenoyltrifluoroacetone) was screened as a carrier to prepare the polymer inclusion membrane (PIM), which was used to separate HA from metal and inorganic acid ions. The experimental results demonstrated that the PIM exhibited good selectivity for HA. During the PIM process, the proton gradient served as a driving force to transport NH2OH(I). The electrodialysis (ED) process was used to efficiently and continuously provide proton gradient without introducing other ions, which coupled with PIM to separate HA. Under the optimum conditions, the separation factors of NH2OH(I)/Na(I) and NH2OH(I)/K(I) were 30.81 and 35.11; the purity of HA was 99.4%, indicating that the PIM-ED process can be used for high-purity preparation of HA.
{"title":"Efficient Separation of Hydroxylamine from Metal Ions by PIM-ED Process","authors":"Lilei Yang, Zhongwei Ding, Zhengtao Zhu, Weidong Zhang","doi":"10.3390/separations12020024","DOIUrl":"https://doi.org/10.3390/separations12020024","url":null,"abstract":"Selective separation of hydroxylamine (HA) from metal ions to prepare high-purity HA remains a challenge. In this study, given that HA can react with carbonyl compounds, TTA (thenoyltrifluoroacetone) was screened as a carrier to prepare the polymer inclusion membrane (PIM), which was used to separate HA from metal and inorganic acid ions. The experimental results demonstrated that the PIM exhibited good selectivity for HA. During the PIM process, the proton gradient served as a driving force to transport NH2OH(I). The electrodialysis (ED) process was used to efficiently and continuously provide proton gradient without introducing other ions, which coupled with PIM to separate HA. Under the optimum conditions, the separation factors of NH2OH(I)/Na(I) and NH2OH(I)/K(I) were 30.81 and 35.11; the purity of HA was 99.4%, indicating that the PIM-ED process can be used for high-purity preparation of HA.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"12 2","pages":"24-24"},"PeriodicalIF":0.0,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2297-8739/12/2/24/pdf?version=1737734113","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, ZnO nanoparticles (ZnO NPs) were synthesized using a green method employing fresh Citrus aurantium L. aqueous extract (CA) as a reducing agent. After preparation, the ZnO NPs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and infrared spectroscopy (IR). The products displayed irregular particle shapes on a nanoscale. The adsorption ability of ZnO NPs was tested with amaranth red dye, and the result showed that it had a satisfied capacity for amaranth red. The adsorption data followed the pseudo-second-order model and the Langmuir model, which indicated the adsorption process was controlled by a chemical adsorption process and occurred homogeneously on the surface of absorbents. In addition, the prepared ZnO NPs also exhibited antibacterial abilities against Staphylococcus aureus and Escherichia coli bacteria; antioxidant activities were observed in 2-2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-di(3-ethylbenzthiazoline sulphonate) (ABTS) radicals scavenging assays and the ferric ion reducing antioxidant power (FRAP) assay, which were better than those of traditional ZnO NPs except in the FRAP assay. Based on these findings, the ZnO NPs fabricated with CA aqueous extract displayed promising abilities in the environmental remediation of dye wastewater.
{"title":"Green Preparation of ZnO Nanoparticles Using Citrus aurantium L. Extract for Dye Adsorption, Antibacterial, and Antioxidant Activities","authors":"Xitao Yang, Liangliang Liu, Chenxiao Chen, Liping Liao, Siqi Huang","doi":"10.3390/separations12020018","DOIUrl":"https://doi.org/10.3390/separations12020018","url":null,"abstract":"In this study, ZnO nanoparticles (ZnO NPs) were synthesized using a green method employing fresh Citrus aurantium L. aqueous extract (CA) as a reducing agent. After preparation, the ZnO NPs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and infrared spectroscopy (IR). The products displayed irregular particle shapes on a nanoscale. The adsorption ability of ZnO NPs was tested with amaranth red dye, and the result showed that it had a satisfied capacity for amaranth red. The adsorption data followed the pseudo-second-order model and the Langmuir model, which indicated the adsorption process was controlled by a chemical adsorption process and occurred homogeneously on the surface of absorbents. In addition, the prepared ZnO NPs also exhibited antibacterial abilities against Staphylococcus aureus and Escherichia coli bacteria; antioxidant activities were observed in 2-2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-di(3-ethylbenzthiazoline sulphonate) (ABTS) radicals scavenging assays and the ferric ion reducing antioxidant power (FRAP) assay, which were better than those of traditional ZnO NPs except in the FRAP assay. Based on these findings, the ZnO NPs fabricated with CA aqueous extract displayed promising abilities in the environmental remediation of dye wastewater.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"12 2","pages":"18-18"},"PeriodicalIF":0.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2297-8739/12/2/18/pdf?version=1737451624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-15DOI: 10.3390/separations12010015
Yue Liu, Rong Guo, Jie Li, Yizhen Cheng, Congmin Wang, Weiqiang Wang, Huifan Zheng
This study investigates the environmental significance of ciprofloxacin as an emerging contaminant and the need for effective degradation methods. The chemical coprecipitation method was used in this study to prepare the Zn-Cu-Ni composite silicate, serving as a heterogeneous ozonation catalyst. The catalytic activity was then evaluated by degrading ciprofloxacin (CIP). Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption, and Fourier transform infrared analysis (FTIR) were used to characterize the Zn-Cu-Ni composite silicate. The catalyst had a high surface area (308.137 m2/g), no regular morphology, and a particle size of 7.6 µm and contained Si-O-Si, Ni-O-Si, and Zn-O-Si. The results showed that the CIP degradation and mineralization rates (pH 7.0, CIP 3.0 mg/L, Ozone 1.5 mg/L) were significantly enhanced in the presence of the Zn-Cu-Ni composite silicate. The CIP and total organic carbon (TOC) removal rates were increased by 51.09% and 18.72%, respectively, under optimal conditions, compared with ozonation alone. The adsorption of Zn-Cu-Ni composite silicate, ozone oxidation, and ·OH oxidation synergistically promoted the efficient removal of CIP. This study provides valuable catalytic ozone technology for degradation of antibiotics in wastewater to reduce environmental pollution with potential practical applications.
{"title":"Enhanced Ciprofloxacin Ozonation Degradation by an Aqueous Zn-Cu-Ni Composite Silicate: Degradation Performance and Surface Mechanism","authors":"Yue Liu, Rong Guo, Jie Li, Yizhen Cheng, Congmin Wang, Weiqiang Wang, Huifan Zheng","doi":"10.3390/separations12010015","DOIUrl":"https://doi.org/10.3390/separations12010015","url":null,"abstract":"This study investigates the environmental significance of ciprofloxacin as an emerging contaminant and the need for effective degradation methods. The chemical coprecipitation method was used in this study to prepare the Zn-Cu-Ni composite silicate, serving as a heterogeneous ozonation catalyst. The catalytic activity was then evaluated by degrading ciprofloxacin (CIP). Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption–desorption, and Fourier transform infrared analysis (FTIR) were used to characterize the Zn-Cu-Ni composite silicate. The catalyst had a high surface area (308.137 m2/g), no regular morphology, and a particle size of 7.6 µm and contained Si-O-Si, Ni-O-Si, and Zn-O-Si. The results showed that the CIP degradation and mineralization rates (pH 7.0, CIP 3.0 mg/L, Ozone 1.5 mg/L) were significantly enhanced in the presence of the Zn-Cu-Ni composite silicate. The CIP and total organic carbon (TOC) removal rates were increased by 51.09% and 18.72%, respectively, under optimal conditions, compared with ozonation alone. The adsorption of Zn-Cu-Ni composite silicate, ozone oxidation, and ·OH oxidation synergistically promoted the efficient removal of CIP. This study provides valuable catalytic ozone technology for degradation of antibiotics in wastewater to reduce environmental pollution with potential practical applications.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"12 1","pages":"15-15"},"PeriodicalIF":0.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2297-8739/12/1/15/pdf?version=1736945924","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147331601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.3390/separations11010019
Ikki Tateishi, M. Furukawa, H. Katsumata, S. Kaneco
B-doped zinc oxide/copper oxide composites prepared using a simple method showed high photocatalytic hydrogen production activity in the presence of aqueous sulfide solutions. Co-modification of the CuO composite with B-doping caused an increase in the charge separation efficiency and light absorption capacity. The sacrificial effect was thermodynamically enhanced by manipulating the composition of the sulfide solution. A maximum hydrogen production activity of 224 μmol g−1 h−1 was achieved under 450 nm light irradiation in a photocatalytic system with optimized B doping, a CuO composite, and a sulfide sacrificial agent concentration.
用简单的方法制备的掺杂了 B 的氧化锌/氧化铜复合材料在硫化物水溶液中显示出很高的光催化制氢活性。用 B 掺杂对氧化铜复合材料进行共修饰可提高电荷分离效率和光吸收能力。通过调节硫化物溶液的成分，牺牲效应在热力学上得到了增强。在优化了 B 掺杂、CuO 复合材料和硫化物牺牲剂浓度的光催化系统中，450 纳米光照射下的最大产氢活性达到了 224 μmol g-1 h-1。
{"title":"Effective Utilization of Sulfur Wastewater by Photocatalytic System Using B/CuO/ZnO","authors":"Ikki Tateishi, M. Furukawa, H. Katsumata, S. Kaneco","doi":"10.3390/separations11010019","DOIUrl":"https://doi.org/10.3390/separations11010019","url":null,"abstract":"B-doped zinc oxide/copper oxide composites prepared using a simple method showed high photocatalytic hydrogen production activity in the presence of aqueous sulfide solutions. Co-modification of the CuO composite with B-doping caused an increase in the charge separation efficiency and light absorption capacity. The sacrificial effect was thermodynamically enhanced by manipulating the composition of the sulfide solution. A maximum hydrogen production activity of 224 μmol g−1 h−1 was achieved under 450 nm light irradiation in a photocatalytic system with optimized B doping, a CuO composite, and a sulfide sacrificial agent concentration.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"8 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.3390/separations11010021
Bogusław Buszewski, Dušan Berek, Virginia Coman
The origin of the International Symposia on Separation Sciences (ISSS) can be found in the national gas chromatography scientific meetings held in Zagreb, Croatia, from 1967 and later at Plitvice Lakes until 1988 [...]
{"title":"Central European Group for Separation Sciences (CEGSS)—Brief History and Memoirs on the Creation and Activity","authors":"Bogusław Buszewski, Dušan Berek, Virginia Coman","doi":"10.3390/separations11010021","DOIUrl":"https://doi.org/10.3390/separations11010021","url":null,"abstract":"The origin of the International Symposia on Separation Sciences (ISSS) can be found in the national gas chromatography scientific meetings held in Zagreb, Croatia, from 1967 and later at Plitvice Lakes until 1988 [...]","PeriodicalId":21833,"journal":{"name":"Separations","volume":"36 18","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.3390/separations11010018
Mohamed A. Abdelaziz, Neil D. Danielson
In this work, three cyanoalkyl silicone GC stationary-phase polymers, namely OV-105, OV-225, and OV-275, were investigated as potential extractants for dispersive liquid–liquid microextraction (DLLME). The OV-225 polymer (cyanopropylmethyl-phenylmethylsilicone) exhibited the cleanest chromatographic background and was extensively studied. The proposed polymer was tested through the DLLME of four non-steroidal anti-inflammatory drugs from aqueous samples, followed by HPLC separation with UV detection at 230 nm. To achieve the maximum enrichment, the experimental conditions that influence the DLLME process were optimized using one-factor-at-a-time and design-of-experiment (DoE) approaches. The extraction variables (polymer mass, dispersive solvent volume, buffer pH, and mixing time) were screened by implementing a two-level full factorial design (FFD). Significant variables were fine-tuned using response surface methodology based on a face-centered central composite design (CCD). The optimum conditions were 10 mg of polymer (extraction medium); 50 µL of tetrahydrofuran (dispersive solvent); 100 µL of phosphate buffer pH 2.75 ([PO43−] = 100 mM); and 3 min of vortex mixing. The addition of salt had a minimal effect on the enrichment factors. In the optimum conditions, enrichment factors up to 46 were achieved using 1.5 mL samples. Calibration curves exhibited correlation coefficients > 0.999 using 4-pentylbenzoic acid as an internal standard. The limits of quantitation were 5 ng/mL for naproxen, 10 ng/mL for diflunisal, 25 ng/mL for indomethacin, and 75 ng/mL for ibuprofen. The analysis of spiked tap water samples showed adequate relative recoveries and precision. In conclusion, the proposed polymer (OV-225) is a potential greener alternative to traditional organic extractants used in DLLME.
{"title":"A Cyanoalkyl Silicone GC Stationary-Phase Polymer as an Extractant for Dispersive Liquid–Liquid Microextraction","authors":"Mohamed A. Abdelaziz, Neil D. Danielson","doi":"10.3390/separations11010018","DOIUrl":"https://doi.org/10.3390/separations11010018","url":null,"abstract":"In this work, three cyanoalkyl silicone GC stationary-phase polymers, namely OV-105, OV-225, and OV-275, were investigated as potential extractants for dispersive liquid–liquid microextraction (DLLME). The OV-225 polymer (cyanopropylmethyl-phenylmethylsilicone) exhibited the cleanest chromatographic background and was extensively studied. The proposed polymer was tested through the DLLME of four non-steroidal anti-inflammatory drugs from aqueous samples, followed by HPLC separation with UV detection at 230 nm. To achieve the maximum enrichment, the experimental conditions that influence the DLLME process were optimized using one-factor-at-a-time and design-of-experiment (DoE) approaches. The extraction variables (polymer mass, dispersive solvent volume, buffer pH, and mixing time) were screened by implementing a two-level full factorial design (FFD). Significant variables were fine-tuned using response surface methodology based on a face-centered central composite design (CCD). The optimum conditions were 10 mg of polymer (extraction medium); 50 µL of tetrahydrofuran (dispersive solvent); 100 µL of phosphate buffer pH 2.75 ([PO43−] = 100 mM); and 3 min of vortex mixing. The addition of salt had a minimal effect on the enrichment factors. In the optimum conditions, enrichment factors up to 46 were achieved using 1.5 mL samples. Calibration curves exhibited correlation coefficients > 0.999 using 4-pentylbenzoic acid as an internal standard. The limits of quantitation were 5 ng/mL for naproxen, 10 ng/mL for diflunisal, 25 ng/mL for indomethacin, and 75 ng/mL for ibuprofen. The analysis of spiked tap water samples showed adequate relative recoveries and precision. In conclusion, the proposed polymer (OV-225) is a potential greener alternative to traditional organic extractants used in DLLME.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"38 3","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.3390/separations11010020
Wenxia Xie, Chunmin Tu, Jun Zhang, Chengwei Xu
The accumulation of uncollected fly ash from flue gas in post-combustion CO2 capture processes is a significant concern in current coal-fired power plants due to its potential impact on the performance of CO2 absorbent and absorption towers. In order to determine the effect of fly ash on the mass transfer performance of CO2 absorption into monoethanolamine (MEA) and diethanolamine (DEA) aqueous solutions, experimental studies were carried out using a small-sized packed tower equipped with θ-ring random packing. These studies were conducted under various operating parameters, including solution temperature, liquid/gas ratio (L/G), packing height, and fly ash concentration. The results show that the effect of fly ash on the outlet CO2 concentration was primarily observed during the initial stages of the experimental process. Moreover, the presence of fly ash leads to a reduction in the volumetric overall mass transfer coefficient (KGav) when using MEA and DEA solution, and increasing the fly ash concentration further exacerbates this negative impact. However, the effect of fly ash on the reduction in KGav is not significantly related to its chemical composition but rather depends on the operational parameters. With increasing solution temperature, liquid/gas ratio (L/G), and packing height, the KGav values for different solutions exhibit an upward trend. The negative effect of fly ash on KGav remains relatively stable for MEA as solution temperature and packing height increase. Compared to MEA, fly ash has a greater negative effect on DEA solution under the same experimental conditions. The analysis reveals that the detrimental effect of fly ash on KGav primarily stems from its ability to alter the distribution state of the absorption liquid within the packed tower.
在目前的燃煤发电厂中，燃烧后二氧化碳捕集过程中烟气中积累的未收集飞灰是一个重大问题，因为它可能会影响二氧化碳吸收剂和吸收塔的性能。为了确定粉煤灰对二氧化碳吸收到单乙醇胺（MEA）和二乙醇胺（DEA）水溶液中的传质性能的影响，我们使用装有θ-环无规填料的小型填料塔进行了实验研究。这些研究是在不同的操作参数下进行的，包括溶液温度、液气比 (L/G)、填料高度和粉煤灰浓度。结果表明，粉煤灰对出口二氧化碳浓度的影响主要体现在实验过程的初始阶段。此外，在使用 MEA 和 DEA 溶液时，粉煤灰的存在会导致体积总传质系数（KGav）降低，而增加粉煤灰浓度会进一步加剧这种负面影响。不过，粉煤灰对 KGav 降低的影响与其化学成分并无明显关系，而是取决于运行参数。随着溶液温度、液气比（L/G）和填料高度的增加，不同溶液的 KGav 值呈上升趋势。随着溶液温度和填料高度的增加，粉煤灰对 MEA KGav 的负面影响保持相对稳定。与 MEA 相比，在相同的实验条件下，粉煤灰对 DEA 溶液的负面影响更大。分析表明，粉煤灰对 KGav 的不利影响主要源于粉煤灰能够改变填料塔内吸收液的分布状态。
{"title":"Effect of Fly Ash on the Mass Transfer Performance of CO2 Removal Using MEA and DEA Solutions in a Packed Tower","authors":"Wenxia Xie, Chunmin Tu, Jun Zhang, Chengwei Xu","doi":"10.3390/separations11010020","DOIUrl":"https://doi.org/10.3390/separations11010020","url":null,"abstract":"The accumulation of uncollected fly ash from flue gas in post-combustion CO2 capture processes is a significant concern in current coal-fired power plants due to its potential impact on the performance of CO2 absorbent and absorption towers. In order to determine the effect of fly ash on the mass transfer performance of CO2 absorption into monoethanolamine (MEA) and diethanolamine (DEA) aqueous solutions, experimental studies were carried out using a small-sized packed tower equipped with θ-ring random packing. These studies were conducted under various operating parameters, including solution temperature, liquid/gas ratio (L/G), packing height, and fly ash concentration. The results show that the effect of fly ash on the outlet CO2 concentration was primarily observed during the initial stages of the experimental process. Moreover, the presence of fly ash leads to a reduction in the volumetric overall mass transfer coefficient (KGav) when using MEA and DEA solution, and increasing the fly ash concentration further exacerbates this negative impact. However, the effect of fly ash on the reduction in KGav is not significantly related to its chemical composition but rather depends on the operational parameters. With increasing solution temperature, liquid/gas ratio (L/G), and packing height, the KGav values for different solutions exhibit an upward trend. The negative effect of fly ash on KGav remains relatively stable for MEA as solution temperature and packing height increase. Compared to MEA, fly ash has a greater negative effect on DEA solution under the same experimental conditions. The analysis reveals that the detrimental effect of fly ash on KGav primarily stems from its ability to alter the distribution state of the absorption liquid within the packed tower.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"9 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139383133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-03DOI: 10.3390/separations11010017
Tao Bai, Yuhu Yao, Jiaxin Zhao, Laixin Tian, Luming Zhang
This study investigated the adsorption performance of hydrothermal carbon derived from banana peel and modified with different concentrations of phosphoric acid solution, then used to adsorb lead ions in an aqueous solution. The surface structure and functional groups of the modified hydrothermal carbon were analyzed using XRD, SEM, FT-IR, elemental analysis, and BET. The results showed that the adsorption capacity of modified hydrothermal carbon derived from banana peel reached 40.64 mg/g at a hydrothermal temperature of 240 °C, a phosphoric acid solution of 2 mol/L, and a solid–liquid ratio of 2 g/L, with a removal efficiency of 82.74%. The adsorption process conformed to the pseudo-second-order kinetic model and the Langmuir isotherm equation. The correlation coefficient of 0.99 for fitting the adsorption process using an artificial neural network, indicating that the artificial neural network could be used to predict adsorption. The adsorption of Pb(II) from an aqueous solution by phosphoric acid-modified hydrothermal carbon was dominated by monolayer chemical adsorption, and the adsorption mechanisms included electrostatic attraction, ion exchange, surface complexation, and physical adsorption.
{"title":"Adsorption Performance and Mechanism of H3PO4-Modified Banana Peel Hydrothermal Carbon on Pb(II)","authors":"Tao Bai, Yuhu Yao, Jiaxin Zhao, Laixin Tian, Luming Zhang","doi":"10.3390/separations11010017","DOIUrl":"https://doi.org/10.3390/separations11010017","url":null,"abstract":"This study investigated the adsorption performance of hydrothermal carbon derived from banana peel and modified with different concentrations of phosphoric acid solution, then used to adsorb lead ions in an aqueous solution. The surface structure and functional groups of the modified hydrothermal carbon were analyzed using XRD, SEM, FT-IR, elemental analysis, and BET. The results showed that the adsorption capacity of modified hydrothermal carbon derived from banana peel reached 40.64 mg/g at a hydrothermal temperature of 240 °C, a phosphoric acid solution of 2 mol/L, and a solid–liquid ratio of 2 g/L, with a removal efficiency of 82.74%. The adsorption process conformed to the pseudo-second-order kinetic model and the Langmuir isotherm equation. The correlation coefficient of 0.99 for fitting the adsorption process using an artificial neural network, indicating that the artificial neural network could be used to predict adsorption. The adsorption of Pb(II) from an aqueous solution by phosphoric acid-modified hydrothermal carbon was dominated by monolayer chemical adsorption, and the adsorption mechanisms included electrostatic attraction, ion exchange, surface complexation, and physical adsorption.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"115 9","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-03DOI: 10.3390/separations11010016
F. Buthmann, Sophia Volpert, J. Koop, Gerhard Schembecker
Centrifugal Partition Chromatography (CPC) utilizes a two-phase liquid–liquid system as mobile and stationary phases. During operation, the latter continuously drains out of the rotor, despite it being in fact stationary, leading to decreasing separation efficiency over time, a phenomenon still poorly understood today because neither simulations nor extensive experimental investigations have addressed this so-called bleeding. With the model presented in this study, the underlying hydrodynamics are discussed in detail. This model can simulate bleeding over 60 s and is verified experimentally for different operating points (volumetric flow rates of 5, 12, and 20 mL⋅min−1) of the Centrifugal Partition Chromatograph utilizing an aqueous–organic phase system. We simulated two interconnected chambers at the rotor inlet and analyzed the loss of the stationary phase over time. The results of the simulated second chamber are closely aligned with the experimental validation results. Thus, the prediction of bleeding utilizing the simulation of hydrodynamics was successful. Moreover, we highlighted the benefits of the two-chamber setup modeled in this study compared to single-chamber models.
{"title":"Prediction of Bleeding via Simulation of Hydrodynamics in Centrifugal Partition Chromatography","authors":"F. Buthmann, Sophia Volpert, J. Koop, Gerhard Schembecker","doi":"10.3390/separations11010016","DOIUrl":"https://doi.org/10.3390/separations11010016","url":null,"abstract":"Centrifugal Partition Chromatography (CPC) utilizes a two-phase liquid–liquid system as mobile and stationary phases. During operation, the latter continuously drains out of the rotor, despite it being in fact stationary, leading to decreasing separation efficiency over time, a phenomenon still poorly understood today because neither simulations nor extensive experimental investigations have addressed this so-called bleeding. With the model presented in this study, the underlying hydrodynamics are discussed in detail. This model can simulate bleeding over 60 s and is verified experimentally for different operating points (volumetric flow rates of 5, 12, and 20 mL⋅min−1) of the Centrifugal Partition Chromatograph utilizing an aqueous–organic phase system. We simulated two interconnected chambers at the rotor inlet and analyzed the loss of the stationary phase over time. The results of the simulated second chamber are closely aligned with the experimental validation results. Thus, the prediction of bleeding utilizing the simulation of hydrodynamics was successful. Moreover, we highlighted the benefits of the two-chamber setup modeled in this study compared to single-chamber models.","PeriodicalId":21833,"journal":{"name":"Separations","volume":"12 8","pages":""},"PeriodicalIF":2.6,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139388610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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