Pub Date : 2024-11-19DOI: 10.1016/j.seppur.2024.130585
Zifang Chi, Xinyang Liu, Huai Li
The compound pollution of nitrate and hexavalent chromium (Cr(VI)) in groundwater poses a serious hazard to human health and ecology. The use of H2-connected graphene oxide loaded nano zero-valent iron (rGO/nZVI) chemical reduction coupled with hydrogen autotrophic bioreduction system is expected to reduce the economic cost and alleviate the problem of gas blockage. In this study, we investigated the process and mechanism of the removal of NO3–/Cr(VI) compound pollution by rGO/nZVI coupled HAM under weak magnetic field (WMF). The results showed that rGO/nZVI coupled HAM system had the highest removal of NO3– (93.8 %), and the allocation ratio of chemical reduction to biological reduction of nitrate was about 4:1. Under the compound pollution conditions, the removal of Cr(VI) in the coupled system could reach 100 %. The abiotic reaction mechanism should be the main pathway for Cr(VI) removal, and the ratio of chemical reduction to biological reduction was 99:1 within 24 h. The results showed that the chemical reduction and biological reduction of Cr(VI) in the coupled system was the most effective way to remove Cr(VI). High N2 conversion of rGO/nZVI coupled with HAM system at 30 mT was obtained (66.98 % and 43.17 %) at NO3– and NO3–/Cr(VI) composite contamination systems, respectively. The presence of WMF corroded rGO/nZVI towards lepidocrocite moving the denitrification process towards harmlessness (high N2 selectivity). This finding provides a theoretical basis of the coupled system of rGO/nZVI and HAM for the groundwater compound pollution removal.
{"title":"Enhanced Cr(VI) and nitrate reduction using rGO/nZVI coupled hydrogen autotrophs under weak magnetic field: Performance and mechanisms","authors":"Zifang Chi, Xinyang Liu, Huai Li","doi":"10.1016/j.seppur.2024.130585","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130585","url":null,"abstract":"The compound pollution of nitrate and hexavalent chromium (Cr(VI)) in groundwater poses a serious hazard to human health and ecology. The use of H<sub>2</sub>-connected graphene oxide loaded nano zero-valent iron (rGO/nZVI) chemical reduction coupled with hydrogen autotrophic bioreduction system is expected to reduce the economic cost and alleviate the problem of gas blockage. In this study, we investigated the process and mechanism of the removal of NO<sub>3</sub><sup>–</sup>/Cr(VI) compound pollution by rGO/nZVI coupled HAM under weak magnetic field (WMF). The results showed that rGO/nZVI coupled HAM system had the highest removal of NO<sub>3</sub><sup>–</sup> (93.8 %), and the allocation ratio of chemical reduction to biological reduction of nitrate was about 4:1. Under the compound pollution conditions, the removal of Cr(VI) in the coupled system could reach 100 %. The abiotic reaction mechanism should be the main pathway for Cr(VI) removal, and the ratio of chemical reduction to biological reduction was 99:1 within 24 h. The results showed that the chemical reduction and biological reduction of Cr(VI) in the coupled system was the most effective way to remove Cr(VI). High N<sub>2</sub> conversion of rGO/nZVI coupled with HAM system at 30 mT was obtained (66.98 % and 43.17 %) at NO<sub>3</sub><sup>–</sup> and NO<sub>3</sub><sup>–</sup>/Cr(VI) composite contamination systems, respectively. The presence of WMF corroded rGO/nZVI towards lepidocrocite moving the denitrification process towards harmlessness (high N<sub>2</sub> selectivity). This finding provides a theoretical basis of the coupled system of rGO/nZVI and HAM for the groundwater compound pollution removal.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"11 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-19DOI: 10.1016/j.seppur.2024.130556
Shuyi Liu, Yinghao Xue, Yan Jia, Hanxue Wang, Qing Nie, Jianwei Fan
Catalytic oxidation of carbon monoxide (CO) has gained increasing interest in recent years due to its promising applications. Cerium-based catalysts have been widely employed in CO oxidation processes due to their reversible oxygen storage/release capacity (OSC), excellent redox activity, and the most abundant rare earth element in the crust (46 ppm). However, conventional CeO2 catalysts still face challenges of insufficient activity and poor stability. Herein, strategies to enhance the activity of CeO2 catalysts are detailed, including crystal facet engineering, metal-support modification, and heteroatom doping. In conclusion, these strategies aim to increase the number of oxygen vacancies, optimize surface active sites, and strengthen the metal-support interaction, thereby significantly improving the activity of catalytic CO oxidation.
近年来，一氧化碳（CO）的催化氧化因其广阔的应用前景而受到越来越多的关注。铈基催化剂具有可逆的储氧/释氧能力（OSC）、出色的氧化还原活性以及地壳中最丰富的稀土元素（46 ppm），因此被广泛应用于一氧化碳氧化过程。然而，传统的 CeO2 催化剂仍然面临着活性不足和稳定性差的挑战。本文详细介绍了提高 CeO2 催化剂活性的策略，包括晶面工程、金属支架改性和杂原子掺杂。总之，这些策略旨在增加氧空位的数量、优化表面活性位点以及加强金属与支撑物之间的相互作用，从而显著提高催化 CO 氧化的活性。
{"title":"Catalytic CO oxidation on CeO2-based materials: Modification strategies, structure-performance relationships, challenges and prospects","authors":"Shuyi Liu, Yinghao Xue, Yan Jia, Hanxue Wang, Qing Nie, Jianwei Fan","doi":"10.1016/j.seppur.2024.130556","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130556","url":null,"abstract":"Catalytic oxidation of carbon monoxide (CO) has gained increasing interest in recent years due to its promising applications. Cerium-based catalysts have been widely employed in CO oxidation processes due to their reversible oxygen storage/release capacity (OSC), excellent redox activity, and the most abundant rare earth element in the crust (46 ppm). However, conventional CeO<sub>2</sub> catalysts still face challenges of insufficient activity and poor stability. Herein, strategies to enhance the activity of CeO<sub>2</sub> catalysts are detailed, including crystal facet engineering, metal-support modification, and heteroatom doping. In conclusion, these strategies aim to increase the number of oxygen vacancies, optimize surface active sites, and strengthen the metal-support interaction, thereby significantly improving the activity of catalytic CO oxidation.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"10 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-efficiency elimination of uranium was a research hotspot from the aspect of nuclear energy development. Metal chelators and porous materials were two cutting-edge technologies for the recovery and separation of uranium from wastewater. However, there was only limited success in transferring the metal coordination function of metal chelators to chemically stable host materials. Herein, oxamic acid (OxA) and glycine (Gly) functionalized MOF-808 were prepared by a simple solvent-assisted ligand incorporation method and used for uranium removal. The ordered porous structure of MOFs provided rapid diffusion channels, and the introduction of amino acids on Zr6 nodes endowed MOF-808 channels more functional groups with strong binding ability and high hydrophily. The MOF-808@OxA exhibited higher elimination ability (qmax = 370.76 mg·g−1), rapider elimination rate (∼40 min), and higher selectivity than those of MOF-808@Gly and original MOF-808 at pH = 5. Particularly, density functional theory calculations revealed that MOF-808@OxA had a stronger affinity for uranium compared to MOF-808@Gly due to the synergistic effect of C = O and –NH2 groups. Thus, this study provided a feasible strategy for modifying MOFs and a promising prospect for MOF-based materials to eliminate uranium from wastewater.
{"title":"Exploiting the nodes of metal-organic framework by grafting functional organic molecules for synergistic uranium extraction","authors":"Zixuan Ma, Chang Sun, Danyan Lin, Wen Yao, Hairui Hou, Dedong Wu, Xinrong Guo, Xin Yu, Xiangxue Wang","doi":"10.1016/j.seppur.2024.130607","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130607","url":null,"abstract":"High-efficiency elimination of uranium was a research hotspot from the aspect of nuclear energy development. Metal chelators and porous materials were two cutting-edge technologies for the recovery and separation of uranium from wastewater. However, there was only limited success in transferring the metal coordination function of metal chelators to chemically stable host materials. Herein, oxamic acid (OxA) and glycine (Gly) functionalized MOF-808 were prepared by a simple solvent-assisted ligand incorporation method and used for uranium removal. The ordered porous structure of MOFs provided rapid diffusion channels, and the introduction of amino acids on Zr<sub>6</sub> nodes endowed MOF-808 channels more functional groups with strong binding ability and high hydrophily. The MOF-808@OxA exhibited higher elimination ability (<em>q</em><sub>max</sub> = 370.76 mg·g<sup>−1</sup>), rapider elimination rate (∼40 min), and higher selectivity than those of MOF-808@Gly and original MOF-808 at pH = 5. Particularly, density functional theory calculations revealed that MOF-808@OxA had a stronger affinity for uranium compared to MOF-808@Gly due to the synergistic effect of C = O and –NH<sub>2</sub> groups. Thus, this study provided a feasible strategy for modifying MOFs and a promising prospect for MOF-based materials to eliminate uranium from wastewater.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"18 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Constructing S-scheme heterojunctions with a robust internal electric field (IEF) to enhance the photocatalytic degradation of chlorinated volatile organic compounds (Cl-VOCs) presents a significant challenge. Herein, an innovative S-scheme heterojunction of N-doped titanium dioxide (TiO2) and tungsten trioxide (WO3) with abundant oxygen vacancies (OVs) was first synthesized and manipulated via an eco-friendly two-step plasma. The charge transfer pathway between TiO2 and WO3 was analyzed using UV–Vis DRS, XPS, UPS, and EPR measurements, confirming the successful formation of the S-scheme heterojunction. Interestingly, two novel types of IEF: stream-type and waterfall-type were first proposed to distinguish the IEF strength before and after regulation. Under visible light, 5NTW with the optimal ratio (4.66 at% nitrogen and 5 wt% WO3) achieved the highest degradation efficiency and carbon dioxide mineralization rate of 95.4% and 94.1% for chlorobenzene, respectively. The performance enhancement was attributed to the fact that N-doping modifies the electronic structure and work function of TiO2, enhancing the Fermi level difference (ΔEf) with WO3. Meanwhile, the plasma treatment roughened the surface topography of the catalyst and increased the content of OVs, which serve as charge traps and bolster active sites. These synergies led to a transformation from a stream-type IEF of TW to a waterfall-type IEF of 5NTW. KPFM, zeta potential tests, and DFT calculations confirmed that the IEF strength and the number of electron transfers in the waterfall-type IEF are 3.17 and 2.04 times greater, respectively, than those in the stream-type IEF. This strategy transcends the limitations of previous work, offering a novel perspective on the integrated optimization of photocatalysts for superior performance and also further broadens the application prospects of nonthermal plasma technology.
{"title":"Plasma-Assisted construction of waterfall-type IEF in N-TiO2/WO3 S-scheme heterojunction for efficient Visible-Light-Driven degradation of Cl-VOCs","authors":"Ran Sun, Yujie Tan, Wei Zhao, Lijie Song, Ruina Zhang, Xingang Liu, Jianyuan Hou, Yuan Yuan, Feng Qin, Danyan Cen, Renxi Zhang","doi":"10.1016/j.seppur.2024.130626","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130626","url":null,"abstract":"Constructing S-scheme heterojunctions with a robust internal electric field (IEF) to enhance the photocatalytic degradation of chlorinated volatile organic compounds (Cl-VOCs) presents a significant challenge. Herein, an innovative S-scheme heterojunction of N-doped titanium dioxide (TiO<sub>2</sub>) and tungsten trioxide (WO<sub>3</sub>) with abundant oxygen vacancies (OVs) was first synthesized and manipulated via an eco-friendly two-step plasma. The charge transfer pathway between TiO<sub>2</sub> and WO<sub>3</sub> was analyzed using UV–Vis DRS, XPS, UPS, and EPR measurements, confirming the successful formation of the S-scheme heterojunction. Interestingly, two novel types of IEF: stream-type and waterfall-type were first proposed to distinguish the IEF strength before and after regulation. Under visible light, 5NTW with the optimal ratio (4.66 at% nitrogen and 5 wt% WO<sub>3</sub>) achieved the highest degradation efficiency and carbon dioxide mineralization rate of 95.4% and 94.1% for chlorobenzene, respectively. The performance enhancement was attributed to the fact that N-doping modifies the electronic structure and work function of TiO<sub>2</sub>, enhancing the Fermi level difference (ΔE<sub>f</sub>) with WO<sub>3</sub>. Meanwhile, the plasma treatment roughened the surface topography of the catalyst and increased the content of OVs, which serve as charge traps and bolster active sites. These synergies led to a transformation from a stream-type IEF of TW to a waterfall-type IEF of 5NTW. KPFM, zeta potential tests, and DFT calculations confirmed that the IEF strength and the number of electron transfers in the waterfall-type IEF are 3.17 and 2.04 times greater, respectively, than those in the stream-type IEF. This strategy transcends the limitations of previous work, offering a novel perspective on the integrated optimization of photocatalysts for superior performance and also further broadens the application prospects of nonthermal plasma technology.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"47 2 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effective removal of elemental mercury (Hg0) is a global challenge due to its toxicity and bioaccumulation threat to public health and ecosystems. Photocatalytic technology by visible light-driven photocatalysts is promising for Hg0 removal. However, effective separation of photocatalyst powders from reaction solution limits its widespread use. To solve the problem, we report for the first time the successful fabrication of recoverable Bi2O2S/Bi5O7I/ZA hydrogel beads for enhanced photocatalytic Hg0 removal in the presence of H2O2. Characterization techniques such as XRD, TEM, EDS, XPS, UV–vis DRS, PL, etc. are employed to understand the physicochemical properties and photoelectric performance of the photocatalysts. The serial BOSI photocatalysts all outperform the single component, which is attributed to the formation of a heterojunction between Bi5O7I and Bi2O2S. The coupling of 2-BOSI-ZA beads with H2O2 shows favorable synergistic effect, with Hg0 removal efficiency in the following order: H2O2 + 2-BOSI-ZA < 2-BOSI-ZA + FSL < H2O2 + 2-BOSI-ZA + FSL. TPC, EIS, and PL tests confirm that the introduction of Bi2O2S effectively suppresses charge carrier recombination. ESR and free radicals capture experiments demonstrate that the main species responsible for removal of Hg0 are •O2– and •OH. Density functional theory calculations exhibit that the internal electric field (IEF) between Bi5O7I and Bi2O2S contributes to the spatial charge separation of the heterojunction. The IEF leads to an S-scheme carrier transfer mechanism at the Bi2O2S/Bi5O7I interface that benefits the carrier separation on Bi5O7I, resulting in an enhanced photocatalytic performance. This work can provide further inspiration for designing hydrogel photocatalysts with an excellent activity in conjunction with oxidants in the field of mercury pollution control.
{"title":"Fabrication of recoverable Bi2O2S/Bi5O7I/ZA hydrogel beads for enhanced photocatalytic Hg0 removal in the presence of H2O2","authors":"Haixing Du, Anchao Zhang, Qianqian Zhang, Yihong Sun, Haowei Zhu, Hua Wang, Zengqiang Tan, Xinmin Zhang, Guoyan Chen","doi":"10.1016/j.seppur.2024.130597","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130597","url":null,"abstract":"The effective removal of elemental mercury (Hg<sup>0</sup>) is a global challenge due to its toxicity and bioaccumulation threat to public health and ecosystems. Photocatalytic technology by visible light-driven photocatalysts is promising for Hg<sup>0</sup> removal. However, effective separation of photocatalyst powders from reaction solution limits its widespread use. To solve the problem, we report for the first time the successful fabrication of recoverable Bi<sub>2</sub>O<sub>2</sub>S/Bi<sub>5</sub>O<sub>7</sub>I/ZA hydrogel beads for enhanced photocatalytic Hg<sup>0</sup> removal in the presence of H<sub>2</sub>O<sub>2</sub>. Characterization techniques such as XRD, TEM, EDS, XPS, UV–vis DRS, PL, etc. are employed to understand the physicochemical properties and photoelectric performance of the photocatalysts. The serial BOSI photocatalysts all outperform the single component, which is attributed to the formation of a heterojunction between Bi<sub>5</sub>O<sub>7</sub>I and Bi<sub>2</sub>O<sub>2</sub>S. The coupling of 2-BOSI-ZA beads with H<sub>2</sub>O<sub>2</sub> shows favorable synergistic effect, with Hg<sup>0</sup> removal efficiency in the following order: H<sub>2</sub>O<sub>2</sub> + 2-BOSI-ZA < 2-BOSI-ZA + FSL < H<sub>2</sub>O<sub>2</sub> + 2-BOSI-ZA + FSL. TPC, EIS, and PL tests confirm that the introduction of Bi<sub>2</sub>O<sub>2</sub>S effectively suppresses charge carrier recombination. ESR and free radicals capture experiments demonstrate that the main species responsible for removal of Hg<sup>0</sup> are <sup>•</sup>O<sub>2</sub><sup>–</sup> and <sup>•</sup>OH. Density functional theory calculations exhibit that the internal electric field (IEF) between Bi<sub>5</sub>O<sub>7</sub>I and Bi<sub>2</sub>O<sub>2</sub>S contributes to the spatial charge separation of the heterojunction. The IEF leads to an S-scheme carrier transfer mechanism at the Bi<sub>2</sub>O<sub>2</sub>S/Bi<sub>5</sub>O<sub>7</sub>I interface that benefits the carrier separation on Bi<sub>5</sub>O<sub>7</sub>I, resulting in an enhanced photocatalytic performance. This work can provide further inspiration for designing hydrogel photocatalysts with an excellent activity in conjunction with oxidants in the field of mercury pollution control.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"18 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-19DOI: 10.1016/j.seppur.2024.130604
Yu Ni, Ruixin Zhao, Mei Jiang, Dongmei Bi, Jiyan Ma, Yongjun Li
The synergistic mechanism of nitrogen-containing chemicals (NCCs) production was explored from the co-pyrolysis of corn cob and the three major biomass components (cellulose, xylan, and lignin) with urea. Compared to individual pyrolysis, the stability of co-pyrolysis oil was significantly enhanced. The three components showed a synergistic effect during co-pyrolysis. The phenolic compounds generated from lignin interacted with the pyran compounds produced from cellulose or xylan. Especially in the presence of urea, this cross-reaction enhanced the formation of nitrogen-containing heterocycles (NHCs). At 500 ℃, the highest yield of NCCs was observed in the co-pyrolysis oil of corn cob and urea, reaching 47.6 wt%. The NHCs exhibited a selectivity of up to 96.9 wt%. the high concentration of urea promoted the pyrolysis of hemicellulose and cellulose, inhibiting the reaction between cellulose-derived products and free amines to form amines. FT-IR analysis of the char revealed that the addition of urea promoted the decomposition of corn cob, enhancing C–H bond breakdown and dehydrogenation reactions. Finally, a potential formation mechanism for The primary NHCs in corn cob pyrolysis oil was pyridine during the co-pyrolysis of corn cob and urea were proposed. The findings of this paper provide theoretical support for the production of NCCs from biomass through the synergistic interaction of its three components.
{"title":"Synergistic effect of nitrogen-rich pyrolysis of three components and nitrogen transformation mechanism","authors":"Yu Ni, Ruixin Zhao, Mei Jiang, Dongmei Bi, Jiyan Ma, Yongjun Li","doi":"10.1016/j.seppur.2024.130604","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130604","url":null,"abstract":"The synergistic mechanism of nitrogen-containing chemicals (NCCs) production was explored from the co-pyrolysis of corn cob and the three major biomass components (cellulose, xylan, and lignin) with urea. Compared to individual pyrolysis, the stability of co-pyrolysis oil was significantly enhanced. The three components showed a synergistic effect during co-pyrolysis. The phenolic compounds generated from lignin interacted with the pyran compounds produced from cellulose or xylan. Especially in the presence of urea, this cross-reaction enhanced the formation of nitrogen-containing heterocycles (NHCs). At 500 ℃, the highest yield of NCCs was observed in the co-pyrolysis oil of corn cob and urea, reaching 47.6 wt%. The NHCs exhibited a selectivity of up to 96.9 wt%. the high concentration of urea promoted the pyrolysis of hemicellulose and cellulose, inhibiting the reaction between cellulose-derived products and free amines to form amines. FT-IR analysis of the char revealed that the addition of urea promoted the decomposition of corn cob, enhancing C–H bond breakdown and dehydrogenation reactions. Finally, a potential formation mechanism for The primary NHCs in corn cob pyrolysis oil was pyridine during the co-pyrolysis of corn cob and urea were proposed. The findings of this paper provide theoretical support for the production of NCCs from biomass through the synergistic interaction of its three components.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"18 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-19DOI: 10.1016/j.seppur.2024.130595
Yue Pan, Zhaoqi Zhu, Min Li, Chenchen Cheng, Mingxing Wang, Rui Jiao, Hanxue Sun, An Li
The application of materials with selective superwettability to oil/water separation has attracted much attention due to frequent oil spills, large discharges of oily wastewater and many shortcomings of traditional separation methods. Herein, we successfully prepared double-defense membranes by co-precipitating dopamine hydrochloride and polyvinyl polyamine on the original commercial hydrophilic polyvinylidene fluoride (PVDF) membrane and coating the membrane with a halloysite-based hydration layer. Our membranes are highly efficient (>99.6 %) in separating oil-in-water emulsions, have outstanding recycle capacity, good anti-fouling properties (underwater oil contact angle of 156.6 ± 1.9°, low oil adhesion), and are resistant to acid, alkali, and salt. Besides, our membranes can also remove different dye solutions through simple filtration. With the advantages of double-defense design, excellent underwater oleophobic performance in various environments, oil–water emulsion separation performance, dye removal function, and low cost, our strategy might provide solutions for treating wastewater containing oil or dye, thus expanding the application range of membrane materials.
{"title":"Preparation of halloysite-based PVDF membrane for effective oil/water separation and dyes removal","authors":"Yue Pan, Zhaoqi Zhu, Min Li, Chenchen Cheng, Mingxing Wang, Rui Jiao, Hanxue Sun, An Li","doi":"10.1016/j.seppur.2024.130595","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130595","url":null,"abstract":"The application of materials with selective superwettability to oil/water separation has attracted much attention due to frequent oil spills, large discharges of oily wastewater and many shortcomings of traditional separation methods. Herein, we successfully prepared double-defense membranes by co-precipitating dopamine hydrochloride and polyvinyl polyamine on the original commercial hydrophilic polyvinylidene fluoride (PVDF) membrane and coating the membrane with a halloysite-based hydration layer. Our membranes are highly efficient (>99.6 %) in separating oil-in-water emulsions, have outstanding recycle capacity, good anti-fouling properties (underwater oil contact angle of 156.6 ± 1.9°, low oil adhesion), and are resistant to acid, alkali, and salt. Besides, our membranes can also remove different dye solutions through simple filtration. With the advantages of double-defense design, excellent underwater oleophobic performance in various environments, oil–water emulsion separation performance, dye removal function, and low cost, our strategy might provide solutions for treating wastewater containing oil or dye, thus expanding the application range of membrane materials.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"1 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amine-functionalized adsorbents possess considerable potential for CO2 capture due to their high selectivity and versatility across a range of applications. However, they are susceptible to CO2-induced chemical deactivation. Despite research efforts to synthesize supports with abundant acid sites to accommodate amines and enhance their stability, information remains sparse on how changes in surface acids impact the CO2 adsorption performance of the resulting adsorbents. In this context, we synthesized porous amorphous SiO2-Al2O3 with varying surface acidity, and impregnated with polyethylenimine (PEI). We then investigated the CO2 adsorption performance under different temperatures, regeneration atmospheres, and humidity levels. The results indicated an optimal adsorption temperature of 75 °C and a pre-treatment temperature of 140 °C. Under these conditions, the Si/Al = 20–60 sample demonstrated the highest capture capacity, approximately 142.6 mg/g. The Avrami model proved most suitable for fitting CO2 adsorption data across various adsorbents, providing an accurate assessment of the entire dynamic adsorption process. However, cycle stability tests revealed that Si/Al = 5–50 had the highest stability among the SiO2-Al2O3 adsorbents in both dry and humid conditions, due to its superior resistance to urea formation. Utilizing FT-IR, solid-state NMR, and XPS analysis, we discovered that the density of moderately strong Lewis acid sites on the surface of SiO2-Al2O3 plays a crucial role in resisting urea formation, as it induces the highest degree of cross-linking reaction between PEI and the porous supports. This breakthrough offers new insights into how the surface acidity of support materials influences the stability of solid amine adsorbents for CO2 capture.
{"title":"CO2 capture performance of amine-functionalized amorphous SiO2-Al2O3 adsorbent: Insights into the support acidity","authors":"Xinlong Yan, Zhongyang Chen, Yingkun Zhu, Xiaoyan Hu, Guojun Kang, Xuehua Shen, Ling Liu, Shijian Lu, Mengqing Hu","doi":"10.1016/j.seppur.2024.130600","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130600","url":null,"abstract":"Amine-functionalized adsorbents possess considerable potential for CO<sub>2</sub> capture due to their high selectivity and versatility across a range of applications. However, they are susceptible to CO<sub>2</sub>-induced chemical deactivation. Despite research efforts to synthesize supports with abundant acid sites to accommodate amines and enhance their stability, information remains sparse on how changes in surface acids impact the CO<sub>2</sub> adsorption performance of the resulting adsorbents. In this context, we synthesized porous amorphous SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub> with varying surface acidity, and impregnated with polyethylenimine (PEI). We then investigated the CO<sub>2</sub> adsorption performance under different temperatures, regeneration atmospheres, and humidity levels. The results indicated an optimal adsorption temperature of 75 °C and a pre-treatment temperature of 140 °C. Under these conditions, the Si/Al = 20–60 sample demonstrated the highest capture capacity, approximately 142.6 mg/g. The Avrami model proved most suitable for fitting CO<sub>2</sub> adsorption data across various adsorbents, providing an accurate assessment of the entire dynamic adsorption process. However, cycle stability tests revealed that Si/Al = 5–50 had the highest stability among the SiO<sub>2</sub>-Al2O<sub>3</sub> adsorbents in both dry and humid conditions, due to its superior resistance to urea formation. Utilizing FT-IR, solid-state NMR, and XPS analysis, we discovered that the density of moderately strong Lewis acid sites on the surface of SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub> plays a crucial role in resisting urea formation, as it induces the highest degree of cross-linking reaction between PEI and the porous supports. This breakthrough offers new insights into how the surface acidity of support materials influences the stability of solid amine adsorbents for CO<sub>2</sub> capture.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"7 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reverse osmosis (RO) membrane technology encounters challenges such as membrane biofouling and oxidation during practical use, which significantly hinders its further development and application. To improve the chlorine and biofouling resistance of RO membrane, we suggest a method that modifies the mass ratios of zwitterionic and quaternary ammonium copolymers in the mussel-inspired coating layer. This method successfully controls the hydrophilicity and positive charge of the membrane surface, enhancing its overall performance. The plate counting results indicate that the bacterial killing efficiency of the blended modified TFC membrane (50:50) against E. coli and S. aureus is ≥98 %. Thanks to the combined effects of the anti-adhesion zwitterionic copolymer and the antibacterial quaternary ammonium copolymer, the blended modified TFC membrane (50:50) demonstrates superior anti-biofouling performance in dynamic biofouling tests. Furthermore, the desalination performance of the blending modified TFC membrane (50:50) remains stable after long-term exposure to 60,000 ppm·h of active chlorine, while the desalination performance of the pristine TFC membrane significantly declines. In conclusion, our advancements in chlorine-tolerant and anti-biofouling RO membranes could enhance the reliability of RO technology.
{"title":"Chlorine-resistant and dual anti-biofouling reverse osmosis membranes with zwitterionic and quaternary ammonium copolymers via mussel-inspired one-step codeposition","authors":"Xinyu Zhang, Chunhui Zhang, Zhenglun Lin, Xinsheng Luo, Jingtao Xu, XiaoXiang Cheng, Daoji Wu, Congwei Luo, Feiyong Chen","doi":"10.1016/j.seppur.2024.130615","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130615","url":null,"abstract":"Reverse osmosis (RO) membrane technology encounters challenges such as membrane biofouling and oxidation during practical use, which significantly hinders its further development and application. To improve the chlorine and biofouling resistance of RO membrane, we suggest a method that modifies the mass ratios of zwitterionic and quaternary ammonium copolymers in the mussel-inspired coating layer. This method successfully controls the hydrophilicity and positive charge of the membrane surface, enhancing its overall performance. The plate counting results indicate that the bacterial killing efficiency of the blended modified TFC membrane (50:50) against <em>E. coli</em> and <em>S. aureus</em> is ≥98 %. Thanks to the combined effects of the anti-adhesion zwitterionic copolymer and the antibacterial quaternary ammonium copolymer, the blended modified TFC membrane (50:50) demonstrates superior anti-biofouling performance in dynamic biofouling tests. Furthermore, the desalination performance of the blending modified TFC membrane (50:50) remains stable after long-term exposure to 60,000 ppm·h of active chlorine, while the desalination performance of the pristine TFC membrane significantly declines. In conclusion, our advancements in chlorine-tolerant and anti-biofouling RO membranes could enhance the reliability of RO technology.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"8 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2024-11-19DOI: 10.1016/j.seppur.2024.130592
Dan Gao, Yuanyuan Cao, Zhaohao Li, Niankun Guo, Hongyuan Zhang
The waste heat utilization in the coal-fired plant has always been one of important ways of the energy saving. In this paper, a novel device is constructed by the combination of the ceramic membrane desorption and the flue gas waste heat utilization. In the device, the absorption solution is the “double-cationic” ionic liquid ([TEPA][1-MIm]). Furthermore, experimental results show that the contact angle of the hydrophobic ceramic membrane is 130°. Under ambient temperature conditions, it is observed that at a concentration of 25 % [TEPA][1-MIm] in an ethylene glycol solution, the maximum absorption amount of CO2 reaches approximately 1.605 mol CO2/mol amine. The saturation time of the absorption is about 20 min. As the concentration of ionic liquids increases, the saturation time gradually extends due to an increase in [TEPA][1-MIm] and consequently higher total CO2 absorption mass. Subsequently, effects of the operating parameters on the desorption rates are analyzed. The contribution of this work is to put forward the idea of utilizing ceramic membranes to recover the waste heat from the flue gas to reduce the CO2 desorption energy consumption. According to experiments, the overall heat transfer coefficient can reach 20.33 W/(m2·K), and the amount of the recovered waste heat can reach 29.97 W.
{"title":"Experimental investigation on the desorption of CO2 enriched liquids based on ceramic membranes","authors":"Dan Gao, Yuanyuan Cao, Zhaohao Li, Niankun Guo, Hongyuan Zhang","doi":"10.1016/j.seppur.2024.130592","DOIUrl":"https://doi.org/10.1016/j.seppur.2024.130592","url":null,"abstract":"The waste heat utilization in the coal-fired plant has always been one of important ways of the energy saving. In this paper, a novel device is constructed by the combination of the ceramic membrane desorption and the flue gas waste heat utilization. In the device, the absorption solution is the “double-cationic” ionic liquid ([TEPA][1-MIm]). Furthermore, experimental results show that the contact angle of the hydrophobic ceramic membrane is 130°. Under ambient temperature conditions, it is observed that at a concentration of 25 % [TEPA][1-MIm] in an ethylene glycol solution, the maximum absorption amount of CO<sub>2</sub> reaches approximately 1.605 mol CO<sub>2</sub>/mol amine. The saturation time of the absorption is about 20 min. As the concentration of ionic liquids increases, the saturation time gradually extends due to an increase in [TEPA][1-MIm] and consequently higher total CO<sub>2</sub> absorption mass. Subsequently, effects of the operating parameters on the desorption rates are analyzed. The contribution of this work is to put forward the idea of utilizing ceramic membranes to recover the waste heat from the flue gas to reduce the CO<sub>2</sub> desorption energy consumption. According to experiments, the overall heat transfer coefficient can reach 20.33 W/(m<sup>2</sup>·K), and the amount of the recovered waste heat can reach 29.97 W.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"26 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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