Pub Date : 2024-12-11DOI: 10.1016/j.micromeso.2024.113444
Amanda C. Marques , Carla V. Soares , Alexandre A. Leitão
First principles calculations based on density functional theory were performed to examine the adsorption behavior of H2O, EtOH, CO2, and a series of sulfur compounds (H2S, COS, Et-SH, Et-S-Met and DMDS) within the UiO-66(Zr) metal–organic framework (MOF) and the CuCl2-loaded UiO-66 (CuCl2@UiO-66). Electronic structure analyses were conducted to characterize the material properties and guide the adsorption site selection within the MOFs pores. Adsorption energies were computed for the guests molecules in their gaseous states, revealing a significant enhancement with CuCl2 loaded in UiO-66. Thermodynamic analysis were also conducted for the adsorption of the guests on CuCl2@UiO-66, revealing that all process are spontaneous and exothermic under standard temperature and pressure conditions. The findings suggest that both UiO-66 and CuCl2@UiO-66 are promising desulfurization adsorbents for Et-SH, DMDS and Et-S-Met in the presence of CO2 and water vapor, with CuCl2@UiO-66 showing superior performance due to favorable interactions between Cu and sulfur.
{"title":"Theoretical insights on the adsorption of sulfur compounds over a CuCl2-loaded Metal–Organic Framework","authors":"Amanda C. Marques , Carla V. Soares , Alexandre A. Leitão","doi":"10.1016/j.micromeso.2024.113444","DOIUrl":"10.1016/j.micromeso.2024.113444","url":null,"abstract":"<div><div>First principles calculations based on density functional theory were performed to examine the adsorption behavior of H<sub>2</sub>O, EtOH, CO<sub>2</sub>, and a series of sulfur compounds (H<sub>2</sub>S, COS, Et-SH, Et-S-Met and DMDS) within the UiO-66(Zr) metal–organic framework (MOF) and the CuCl<sub>2</sub>-loaded UiO-66 (CuCl<sub>2</sub>@UiO-66). Electronic structure analyses were conducted to characterize the material properties and guide the adsorption site selection within the MOFs pores. Adsorption energies were computed for the guests molecules in their gaseous states, revealing a significant enhancement with CuCl<sub>2</sub> loaded in UiO-66. Thermodynamic analysis were also conducted for the adsorption of the guests on CuCl<sub>2</sub>@UiO-66, revealing that all process are spontaneous and exothermic under standard temperature and pressure conditions. The findings suggest that both UiO-66 and CuCl<sub>2</sub>@UiO-66 are promising desulfurization adsorbents for Et-SH, DMDS and Et-S-Met in the presence of CO<sub>2</sub> and water vapor, with CuCl<sub>2</sub>@UiO-66 showing superior performance due to favorable interactions between Cu and sulfur.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113444"},"PeriodicalIF":4.8,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fine-tuning of active sites in zeolites makes it possible to achieve targeted catalytic activity for many industrial processes. Incorporation of zinc into aluminum-free zeolites grants Lewis acidity while simultaneously creating divalent cation exchange positions. Unfortunately, verification and quantification of zinc sites in zeolites is particularly arduous because metal insertion is accompanied by the formation of extra-framework zinc (hydr)oxide phases, which does not offer the desired properties but also carry some Lewis acidity, leading to difficulty in distinguishing between the two. Here, we present a rigorous characterization of (supposedly) Zn-substituted MFI zeolites. For this, two series of Zn-MFI zeolites were prepared, one via classic batch and the other via the recently invented Electro-Assisted Synthesis (EAS) approach, and these were further benchmarked against Zn-impregnated samples. A suite of analytical techniques was used, among which divalent cation capacity (DCC), infrared spectroscopy (FT-IR), and X-ray absorption spectroscopy (XAS) were proven to be the most efficient. Particularly, DCC highlights the framework Zn stability and ability towards exchange of divalent ions. FT-IR spectroscopy demonstrates the healing of silanol nests upon Zn incorporation into the framework. Additionally, a consistent band at around 525 cm−1 was assigned to framework Zn-MFI vibrations. Furthermore, pyridine adsorption followed by FT-IR revealed a shift in the position of Lewis acid sites peak, when comparing Zn- and Al-MFI, while confirming the absence of Lewis acidity for zinc (hydr)oxide phases. Eventually, XAS complemented our findings by distinguishing two types of ZnII species among prepared zeolites.
{"title":"The pursuit of framework zinc affirmation in zincosilicate zeolites: Clues from conventional and spectroscopic characterization","authors":"Gleb Ivanushkin , Ibrahim Khalil , Mostafa Torka Beydokhti , Aram Bugaev , Juna Bae , Thibaut Donckels , Michiel Dusselier","doi":"10.1016/j.micromeso.2024.113449","DOIUrl":"10.1016/j.micromeso.2024.113449","url":null,"abstract":"<div><div>Fine-tuning of active sites in zeolites makes it possible to achieve targeted catalytic activity for many industrial processes. Incorporation of zinc into aluminum-free zeolites grants Lewis acidity while simultaneously creating divalent cation exchange positions. Unfortunately, verification and quantification of zinc sites in zeolites is particularly arduous because metal insertion is accompanied by the formation of extra-framework zinc (hydr)oxide phases, which does not offer the desired properties but also carry some Lewis acidity, leading to difficulty in distinguishing between the two. Here, we present a rigorous characterization of (supposedly) Zn-substituted MFI zeolites. For this, two series of Zn-MFI zeolites were prepared, one via classic batch and the other via the recently invented Electro-Assisted Synthesis (EAS) approach, and these were further benchmarked against Zn-impregnated samples. A suite of analytical techniques was used, among which divalent cation capacity (DCC), infrared spectroscopy (FT-IR), and X-ray absorption spectroscopy (XAS) were proven to be the most efficient. Particularly, DCC highlights the framework Zn stability and ability towards exchange of divalent ions. FT-IR spectroscopy demonstrates the healing of silanol nests upon Zn incorporation into the framework. Additionally, a consistent band at around 525 cm<sup>−1</sup> was assigned to framework Zn-MFI vibrations. Furthermore, pyridine adsorption followed by FT-IR revealed a shift in the position of Lewis acid sites peak, when comparing Zn- and Al-MFI, while confirming the absence of Lewis acidity for zinc (hydr)oxide phases. Eventually, XAS complemented our findings by distinguishing two types of Zn<sup>II</sup> species among prepared zeolites.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"387 ","pages":"Article 113449"},"PeriodicalIF":4.8,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work aimed to study the development of ethylene production through the catalytic dehydration of ethanol using SUZ‒4 zeolitesynthesized from rice husk ash. The optimal conditions for zeolite synthesis, which were tested in the catalytic dehydration process, included a molar ratio of 50 R:50 S and a hydrothermal temperature of 150 °C for 4 days. Under these conditions, the SUZ‒4 zeolite exhibited high crystallinity (97.4 %) and a well‒distributed microporous structure on the catalytic surface, with a pore volume of 0.137 cm3/g and pore sizes ranging from 4.33 to 7.65 Å. The multichannel porous structure further enhanced the selectivity of reactant and product molecules. The zeolite also exhibited a high concentration of weak acid sites (0.787 mmol/g), which are crucial for catalyzing the reaction. Additionally, an investigation into a W/F ratio of 4.45–4.96 gcat./mmolEtOH·min⁻1 showed that this range was optimal for efficiency, highlighting the importance of balancing the catalyst amount with ethanol molecules for effective catalysis at 300 °C. Ethanol conversion reached 99.75 %, and the ethylene yield was 81.28 %. Over a 33‒hour period, the stability of the SUZ‒4 zeolite maintained the ethanol percentage above 90 %. After coke formation on the SUZ‒4 catalyst surface, the zeolite was regenerated, and the ethylene yield remained between 70 and 80 % over 4 regeneration cycles, demonstrating the catalyst's reuse efficiency. Finally, under the optimal conditions for SUZ‒4 zeolite synthesis and catalytic dehydration, a scale‒up experiment was conducted using a packed‒bed reactor 250 times the original size. The results showed that both ethylene yield and ethanol conversion remained consistent.
{"title":"Performance of catalytic dehydration of ethanol to ethylene using SUZ–4 zeolite synthesized from rice husk ash in a packed–bed reactor","authors":"Tanongsak Sukkasem, Thitipob Sirisoontornpanit, Supunnee Junpirom","doi":"10.1016/j.micromeso.2024.113446","DOIUrl":"10.1016/j.micromeso.2024.113446","url":null,"abstract":"<div><div>This work aimed to study the development of ethylene production through the catalytic dehydration of ethanol using SUZ‒4 zeolitesynthesized from rice husk ash. The optimal conditions for zeolite synthesis, which were tested in the catalytic dehydration process, included a molar ratio of 50 R:50 S and a hydrothermal temperature of 150 °C for 4 days. Under these conditions, the SUZ‒4 zeolite exhibited high crystallinity (97.4 %) and a well‒distributed microporous structure on the catalytic surface, with a pore volume of 0.137 cm<sup>3</sup>/g and pore sizes ranging from 4.33 to 7.65 Å. The multichannel porous structure further enhanced the selectivity of reactant and product molecules. The zeolite also exhibited a high concentration of weak acid sites (0.787 mmol/g), which are crucial for catalyzing the reaction. Additionally, an investigation into a W/F ratio of 4.45–4.96 g<sub>cat.</sub>/mmol<sub>EtOH</sub>·min⁻<sup>1</sup> showed that this range was optimal for efficiency, highlighting the importance of balancing the catalyst amount with ethanol molecules for effective catalysis at 300 °C. Ethanol conversion reached 99.75 %, and the ethylene yield was 81.28 %. Over a 33‒hour period, the stability of the SUZ‒4 zeolite maintained the ethanol percentage above 90 %. After coke formation on the SUZ‒4 catalyst surface, the zeolite was regenerated, and the ethylene yield remained between 70 and 80 % over 4 regeneration cycles, demonstrating the catalyst's reuse efficiency. Finally, under the optimal conditions for SUZ‒4 zeolite synthesis and catalytic dehydration, a scale‒up experiment was conducted using a packed‒bed reactor 250 times the original size. The results showed that both ethylene yield and ethanol conversion remained consistent.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113446"},"PeriodicalIF":4.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-09DOI: 10.1016/j.micromeso.2024.113450
Nitin Gumber , Rajesh V. Pai , Anil Boda , S.K. Musharaf Ali
In pursuit of clean energy, nuclear field is growing at a rapid pace. To obtain sustainable power production, a large amount of uranium is required which makes it imperative to recover uranium present from different aqueous streams. Thus, this manuscript focuses on the synthesis of UiO-66 (Ce)-NH2 MOF at ambient conditions and the uranium adsorption studies from aqueous solution. The MOF was thoroughly characterized using different conventional techniques as described in the manuscript. The γ-radiation stability revealed it to be stable up to 1000 kGy of dose. The synthesized MOF exhibited high surface area of 677 m2 g−1 and displayed a remarkable uptake of uranium. The stability of synthesized MOF was evaluated under different pH conditions and solvents as mentioned in the manuscript. The adsorption characteristics were evaluated by varying the pH from 2 to 8, time of adsorption, initial concentration of uranium (25–400 mg/L) etc. pH 5 was observed to be ideal with equilibration time of 4 h and followed Pseduo Second Order model implying chemisorption as the main driving force. The Maximum adsorption capacity of ∼321 mg/g was observed using Langmuir isotherm model which is higher than many other reported adsorbents as described in the main text. Adsorption capacity was independent of ionic strength which suggests inner sphere complexation. Further, the reusability studies showed the potential of MOF to be utilized atleast 3 times without any much loss in the adsorption capacity. The selectivity studies towards U in presence of different metal ions like Ni, Cu, K, Co, Fe, La showed MOF to be fairly selective towards U under experimental conditions and plausible mechanism of adsorption are also reported. Additionally, some insights regarding selective adsorption among different metal ions through computational methodology are depicted. Finally, a plausible mechanism of adsorption was deciphered through use of different techniques such as XRD, FT-IR and XPS which elucidated that the adsorption was governed mainly through chelation of NH2 groups. Thus, the state of art in the field of MOFs is growing exponentially which could use be used to develop more advanced materials with superior adsorption characteristics.
{"title":"Boosting the uranium adsorption capacity of UiO-66 (Ce) by incorporation of amino groups: Experimental and theoretical perspective","authors":"Nitin Gumber , Rajesh V. Pai , Anil Boda , S.K. Musharaf Ali","doi":"10.1016/j.micromeso.2024.113450","DOIUrl":"10.1016/j.micromeso.2024.113450","url":null,"abstract":"<div><div>In pursuit of clean energy, nuclear field is growing at a rapid pace. To obtain sustainable power production, a large amount of uranium is required which makes it imperative to recover uranium present from different aqueous streams. Thus, this manuscript focuses on the synthesis of UiO-66 (Ce)-NH<sub>2</sub> MOF at ambient conditions and the uranium adsorption studies from aqueous solution. The MOF was thoroughly characterized using different conventional techniques as described in the manuscript. The γ-radiation stability revealed it to be stable up to 1000 kGy of dose. The synthesized MOF exhibited high surface area of 677 m<sup>2</sup> g<sup>−1</sup> and displayed a remarkable uptake of uranium. The stability of synthesized MOF was evaluated under different pH conditions and solvents as mentioned in the manuscript. The adsorption characteristics were evaluated by varying the pH from 2 to 8, time of adsorption, initial concentration of uranium (25–400 mg/L) etc. pH 5 was observed to be ideal with equilibration time of 4 h and followed Pseduo Second Order model implying chemisorption as the main driving force. The Maximum adsorption capacity of ∼321 mg/g was observed using Langmuir isotherm model which is higher than many other reported adsorbents as described in the main text. Adsorption capacity was independent of ionic strength which suggests inner sphere complexation. Further, the reusability studies showed the potential of MOF to be utilized atleast 3 times without any much loss in the adsorption capacity. The selectivity studies towards U in presence of different metal ions like Ni, Cu, K, Co, Fe, La showed MOF to be fairly selective towards U under experimental conditions and plausible mechanism of adsorption are also reported. Additionally, some insights regarding selective adsorption among different metal ions through computational methodology are depicted. Finally, a plausible mechanism of adsorption was deciphered through use of different techniques such as XRD, FT-IR and XPS which elucidated that the adsorption was governed mainly through chelation of NH<sub>2</sub> groups. Thus, the state of art in the field of MOFs is growing exponentially which could use be used to develop more advanced materials with superior adsorption characteristics.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113450"},"PeriodicalIF":4.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-08DOI: 10.1016/j.micromeso.2024.113448
Run Zou , Li Lyu , Sarayute Chansai , Joseph Hurd , Ruojia Xin , Jared An Cheang Wong , Daniel Lee , Christopher Hardacre , Yilai Jiao , Xiaolei Fan , Xiaoxia Ou
Cellulose nanocrystals (CNCs) are biomass-derived materials with tunable surface properties, which can be used as additives for facilitating mesoporous zeolite synthesis. Herein, cationic cellulose nanocrystals (quaternary ammonium-modified, CNC-N) and unmodified cellulose nanocrystals (hydroxyl-terminated, CNC-OH) were employed to assist the synthesis of mesoporous silicalite-1 (S-1) zeolites with the reduced usage of tetrapropylammonium (TPA, TPA/SiO2 = 0.04). Parametric studies were conducted to obtain the well-crystallised mesoporous S-1 zeolites. Results showed that the CNC-N could more effectively produce hydrophobic S-1 zeolites with fewer internal silanol defects and higher mesoporosity (e.g., mesoporosity, fmeso, was 31, 20 and 22 % for S-1 templated by CNC-N, CNC-OH and without CNCs, respectively), which was expected to favour the adsorption of non-polar volatile organic compounds (VOCs). According to the characterisation data of the materials at different stages of the synthesis, the CNC-N could induce strong interaction with the anionic silicate species (via electrostatic force), resulting in ‘deposition’ of silicate and TPA on CNC-N, which exhibited slow non-classical crystallisation behaviour that led to the formation of intergrown S-1 (explaining the improved mesoporosity) with fewer internal silanol defects (due to the slow crystallisation). The obtained mesoporous S-1 showed improved performance in toluene adsorption compared to other reference zeolites under investigation. Findings of the work demonstrated the potential of cationic CNCs as the additives for pore/silanol defects engineering of zeolitic materials.
{"title":"Cationic cellulose nanocrystals assisted synthesis of mesoporous Silicalite-1 zeolites with fewer silanol defects","authors":"Run Zou , Li Lyu , Sarayute Chansai , Joseph Hurd , Ruojia Xin , Jared An Cheang Wong , Daniel Lee , Christopher Hardacre , Yilai Jiao , Xiaolei Fan , Xiaoxia Ou","doi":"10.1016/j.micromeso.2024.113448","DOIUrl":"10.1016/j.micromeso.2024.113448","url":null,"abstract":"<div><div>Cellulose nanocrystals (CNCs) are biomass-derived materials with tunable surface properties, which can be used as additives for facilitating mesoporous zeolite synthesis. Herein, cationic cellulose nanocrystals (quaternary ammonium-modified, CNC-N) and unmodified cellulose nanocrystals (hydroxyl-terminated, CNC-OH) were employed to assist the synthesis of mesoporous silicalite-1 (S-1) zeolites with the reduced usage of tetrapropylammonium (TPA, TPA/SiO<sub>2</sub> = 0.04). Parametric studies were conducted to obtain the well-crystallised mesoporous S-1 zeolites. Results showed that the CNC-N could more effectively produce hydrophobic S-1 zeolites with fewer internal silanol defects and higher mesoporosity (e.g., mesoporosity, <em>f</em><sub><em>meso</em></sub>, was 31, 20 and 22 % for S-1 templated by CNC-N, CNC-OH and without CNCs, respectively), which was expected to favour the adsorption of non-polar volatile organic compounds (VOCs). According to the characterisation data of the materials at different stages of the synthesis, the CNC-N could induce strong interaction with the anionic silicate species (<em>via</em> electrostatic force), resulting in ‘deposition’ of silicate and TPA on CNC-N, which exhibited slow non-classical crystallisation behaviour that led to the formation of intergrown S-1 (explaining the improved mesoporosity) with fewer internal silanol defects (due to the slow crystallisation). The obtained mesoporous S-1 showed improved performance in toluene adsorption compared to other reference zeolites under investigation. Findings of the work demonstrated the potential of cationic CNCs as the additives for pore/silanol defects engineering of zeolitic materials.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113448"},"PeriodicalIF":4.8,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-07DOI: 10.1016/j.micromeso.2024.113447
Shuting Du, Tianyang Wang, Wanyu Dou, Jinxu Feng, Yue Huang, Chengpeng Li
Deep oxidative desulfurization from hydrocarbon fuels has attracted an extensive attention of researchers owing to it can be reduced the toxic sulfur dioxide emissions efficiently during combustion. In this work, we identify the ordered mesoporous structure of hierarchical TS-1 as a key factor in enhancing catalytic performance for oxidative desulfurization reactions. We synthesized an intracrystalline ordered mesoporous TS-1 catalyst by introducing a geometrically compatible surfactant containing a diquaternary ammonium group, an azobenzene segment, and an appropriately sized hydrophobic alkyl tail. The developed hierarchical TS-1 catalyst exhibits superior catalytic activity in the oxidative reaction of dibenzothiophene across various temperatures, outperforming several typical hierarchical porous TS-1 catalysts reported in the literature, even at a lower reaction temperature of 30 °C. This innovative ordered mesoporous TS-1 not only presents a promising catalyst for future deep desulfurization applications but also introduces a novel strategy for designing efficient hierarchical catalytic materials through structural optimization.
{"title":"The ordered mesoporous TS-1 synthesized with geometrically matched surfactant and its application in the deep oxidative desulfurization","authors":"Shuting Du, Tianyang Wang, Wanyu Dou, Jinxu Feng, Yue Huang, Chengpeng Li","doi":"10.1016/j.micromeso.2024.113447","DOIUrl":"10.1016/j.micromeso.2024.113447","url":null,"abstract":"<div><div>Deep oxidative desulfurization from hydrocarbon fuels has attracted an extensive attention of researchers owing to it can be reduced the toxic sulfur dioxide emissions efficiently during combustion. In this work, we identify the ordered mesoporous structure of hierarchical TS-1 as a key factor in enhancing catalytic performance for oxidative desulfurization reactions. We synthesized an intracrystalline ordered mesoporous TS-1 catalyst by introducing a geometrically compatible surfactant containing a diquaternary ammonium group, an azobenzene segment, and an appropriately sized hydrophobic alkyl tail. The developed hierarchical TS-1 catalyst exhibits superior catalytic activity in the oxidative reaction of dibenzothiophene across various temperatures, outperforming several typical hierarchical porous TS-1 catalysts reported in the literature, even at a lower reaction temperature of 30 °C. This innovative ordered mesoporous TS-1 not only presents a promising catalyst for future deep desulfurization applications but also introduces a novel strategy for designing efficient hierarchical catalytic materials through structural optimization.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113447"},"PeriodicalIF":4.8,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-06DOI: 10.1016/j.micromeso.2024.113443
Viktoriia D. Kazakova, Nina B. Rozhmanova, Sergey N. Lanin, Pavel N. Nesterenko
The retention regularities on a column packed with microspherical zeolite 13X particles were studied for different classes of compounds (alkanes, aromatic substances, oxygen-, nitrogen-, chlorine-, and sulfur- containing compounds) under conditions of hydrophilic interaction liquid chromatography (HILIC) using methanol and acetonitrile as mobile phases. In general, the retention (logk’) of studied substances having kinetic diameter less than zeolite pore size is proportional to their polarity. The retention of organic substances was compared for 13X and mesoporous silica columns. A special attention was paid to the retention of n- and iso-alcohols homologues, for which a electrostatically induced sieving effect was observed. It was found that retention factors (k’) of solutes on 13X depend strongly on flow rate of the mobile phases indicating the presence of kinetic selectivity effect for the micrporous adsorbent. For the first time the baseline separation was obtained for the low homologues of n-alkanols. Also, selective separation of methanol and methanol-d4 (selectivity α = 1.274; resolution of peaks RS = 1.32) is achieved on 50 × 4.6 mm I.D. column with acetonitrile as the eluent.
{"title":"Retention regularities of alkanols and other small organic molecules on 13X zeolite under HILIC conditions","authors":"Viktoriia D. Kazakova, Nina B. Rozhmanova, Sergey N. Lanin, Pavel N. Nesterenko","doi":"10.1016/j.micromeso.2024.113443","DOIUrl":"10.1016/j.micromeso.2024.113443","url":null,"abstract":"<div><div>The retention regularities on a column packed with microspherical zeolite 13X particles were studied for different classes of compounds (alkanes, aromatic substances, oxygen-, nitrogen-, chlorine-, and sulfur- containing compounds) under conditions of hydrophilic interaction liquid chromatography (HILIC) using methanol and acetonitrile as mobile phases. In general, the retention (log<em>k’</em>) of studied substances having kinetic diameter less than zeolite pore size is proportional to their polarity. The retention of organic substances was compared for 13X and mesoporous silica columns. A special attention was paid to the retention of <em>n-</em> and <em>iso-</em>alcohols homologues, for which a electrostatically induced sieving effect was observed. It was found that retention factors (<em>k’</em>) of solutes on 13X depend strongly on flow rate of the mobile phases indicating the presence of kinetic selectivity effect for the micrporous adsorbent. For the first time the baseline separation was obtained for the low homologues of <em>n</em>-alkanols. Also, selective separation of methanol and methanol-d<sub>4</sub> (selectivity <em>α</em> = 1.274; resolution of peaks <em>R</em><sub>S</sub> = 1.32) is achieved on 50 × 4.6 mm I.D. column with acetonitrile as the eluent.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113443"},"PeriodicalIF":4.8,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-05DOI: 10.1016/j.micromeso.2024.113445
Carlos W. Dos Santos Moraes , P. Gómez Bernabéu , Katia J. Gómez Villegas , E. Guillén Bas , I. Martínez López , A. Davó Quiñonero , D. Fairén Jiménez , D. Lozano Castelló , A. Bueno López Prof.
UiO-66 was synthesized using ZrOCl2·8H2O as metal precursor, and CuO/CeO2/UiO-66 catalysts were prepared and tested for preferential CO oxidation in H2-rich streams (CO-PROX reaction), a reaction of practical significance in hydrogen purification for fuel cells. The study highlights the detrimental effect of residual chlorine anions from UiO-66 synthesis and DMF washing on the catalytic performance of CuO/CeO2/UiO-66. An activation strategy involving rigorous water washing and thermal treatment at 160 °C under CO-PROX conditions was developed. Both steps were deemed necessary, as employing only one proved insufficient to reduce chlorine levels to non-poisoning thresholds. This activation procedure does compromise UiO-66 crystallinity and porosity, but it is justified by achieving a fully functional catalyst. TEM images confirm the uniform dispersion of the CuO/CeO2 active phase on the UiO-66 matrix post-activation and after catalytic testing. A 16-h CO-PROX test at 160 °C with the CuO/CeO2/UiO-66 catalyst, once activated, demonstrated stable performance throughout the extended long-term experiment. This research provides valuable insights into optimizing CuO/CeO2/UiO-66 catalysts for CO-PROX application.
{"title":"Poisoning effect of chlorine anions in the catalytic activity of CuO/CeO2/UiO-66 for CO-PROX reaction and strategy for catalyst activation","authors":"Carlos W. Dos Santos Moraes , P. Gómez Bernabéu , Katia J. Gómez Villegas , E. Guillén Bas , I. Martínez López , A. Davó Quiñonero , D. Fairén Jiménez , D. Lozano Castelló , A. Bueno López Prof.","doi":"10.1016/j.micromeso.2024.113445","DOIUrl":"10.1016/j.micromeso.2024.113445","url":null,"abstract":"<div><div>UiO-66 was synthesized using ZrOCl<sub>2</sub>·8H<sub>2</sub>O as metal precursor, and CuO/CeO<sub>2</sub>/UiO-66 catalysts were prepared and tested for preferential CO oxidation in H<sub>2-</sub>rich streams (CO-PROX reaction), a reaction of practical significance in hydrogen purification for fuel cells. The study highlights the detrimental effect of residual chlorine anions from UiO-66 synthesis and DMF washing on the catalytic performance of CuO/CeO<sub>2</sub>/UiO-66. An activation strategy involving rigorous water washing and thermal treatment at 160 °C under CO-PROX conditions was developed. Both steps were deemed necessary, as employing only one proved insufficient to reduce chlorine levels to non-poisoning thresholds. This activation procedure does compromise UiO-66 crystallinity and porosity, but it is justified by achieving a fully functional catalyst. TEM images confirm the uniform dispersion of the CuO/CeO<sub>2</sub> active phase on the UiO-66 matrix post-activation and after catalytic testing. A 16-h CO-PROX test at 160 °C with the CuO/CeO<sub>2</sub>/UiO-66 catalyst, once activated, demonstrated stable performance throughout the extended long-term experiment. This research provides valuable insights into optimizing CuO/CeO<sub>2</sub>/UiO-66 catalysts for CO-PROX application.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113445"},"PeriodicalIF":4.8,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-04DOI: 10.1016/j.micromeso.2024.113442
Abrar A. Elhussien , Ismail Abdulazeez , Hassan Alasiri , Wael A. Fouad
The need for efficient separation of hydrofluorocarbons for recycling and environmental protection is critical due to their substantial impact on global warming. However, conventional methods such as cryogenic distillation face significant limitations due to the azeotropic behavior of many of these hydrofluorocarbons. This study evaluates the adsorption behavior of various hydrofluorocarbons in zeolite structures, specifically Linde Type A (3A, 4A, and 5A) and Faujasite Type X (13X), using molecular dynamics and grand canonical Monte Carlo simulations. The simulations were validated against experimental data, confirming the reliability of the computational models. Adsorption isotherms were fitted using the Langmuir-Freundlich model to describe the adsorption behavior across different pressures. Focusing on fluoromethane derivatives, the study highlighted key interactions and adsorption capacities in various zeolites. The isotherms of various hydrofluorocarbons in zeolite 13X were explored, revealing differential adsorption based on molecular structure. The potential for using zeolite 13X and 5A to separate refrigerant mixtures was also studied, showing distinct selectivity patterns. Additionally, the temperature dependence of adsorption isotherms and isosteric heat was studied to gain insights into the thermodynamics of the adsorption processes. Key results indicate that zeolite 13X demonstrates strong cation-fluorine interactions, particularly effective for the adsorption of large hydrofluorocarbon molecules, which preferentially occupy 12-membered ring windows. In contrast, zeolite 5A exhibited predominant hydrogen bonding interactions at low pressures, with hydrofluorocarbon molecules occupying the smaller 8-membered ring windows. These findings underscore the selective adsorption capabilities of these zeolites, highlighting their potential application in hydrofluorocarbon separation and recycling processes.
{"title":"Exploring zeolite potential for hydrofluorocarbon capture and recycling: Insights from molecular simulations","authors":"Abrar A. Elhussien , Ismail Abdulazeez , Hassan Alasiri , Wael A. Fouad","doi":"10.1016/j.micromeso.2024.113442","DOIUrl":"10.1016/j.micromeso.2024.113442","url":null,"abstract":"<div><div>The need for efficient separation of hydrofluorocarbons for recycling and environmental protection is critical due to their substantial impact on global warming. However, conventional methods such as cryogenic distillation face significant limitations due to the azeotropic behavior of many of these hydrofluorocarbons. This study evaluates the adsorption behavior of various hydrofluorocarbons in zeolite structures, specifically Linde Type A (3A, 4A, and 5A) and Faujasite Type X (13X), using molecular dynamics and grand canonical Monte Carlo simulations. The simulations were validated against experimental data, confirming the reliability of the computational models. Adsorption isotherms were fitted using the Langmuir-Freundlich model to describe the adsorption behavior across different pressures. Focusing on fluoromethane derivatives, the study highlighted key interactions and adsorption capacities in various zeolites. The isotherms of various hydrofluorocarbons in zeolite 13X were explored, revealing differential adsorption based on molecular structure. The potential for using zeolite 13X and 5A to separate refrigerant mixtures was also studied, showing distinct selectivity patterns. Additionally, the temperature dependence of adsorption isotherms and isosteric heat was studied to gain insights into the thermodynamics of the adsorption processes. Key results indicate that zeolite 13X demonstrates strong cation-fluorine interactions, particularly effective for the adsorption of large hydrofluorocarbon molecules, which preferentially occupy 12-membered ring windows. In contrast, zeolite 5A exhibited predominant hydrogen bonding interactions at low pressures, with hydrofluorocarbon molecules occupying the smaller 8-membered ring windows. These findings underscore the selective adsorption capabilities of these zeolites, highlighting their potential application in hydrofluorocarbon separation and recycling processes.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113442"},"PeriodicalIF":4.8,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-02DOI: 10.1016/j.micromeso.2024.113441
Manjusha J. Gavhane , R.K. Jha , Kyung-Wan Nam , Deu S. Bhange
The current article reports preparation and structural analysis of NH4+ exchanged form of synthetic natrolite zeolite (NH4-natrolite) with disordered structure wherein Si and Al occupies all the tetrahedral (T) sites in the zeolite framework. Structural data is used to gain insight into the structural parameters those influence thermal stability of its proposed H-form. NH4-natrolite is prepared by ion-exchange method from K-natrolite (which was also obtained by ion-exchange with Na-natrolite). Na-natrolite, K-natrolite and NH4-natrolite prepared in this study were tested for their structural, morphological and thermal analysis. Synchrotron X-ray diffraction data was utilized to estimate the crystal structures of hydrated forms of Na-natrolite, K-natrolite and NH4-exchanged natrolites. Thermal analysis of NH4-natrolite revealed that the dehydration is followed by removal of ammonia during calcination. The role of the size (radius) and nature (either divalent or monovalent) of the exchangeable cations present in the channels, the framework chemical content and extent of ‘T’ atom ordering have been collectively discussed and correlated with the structural behaviour of calcined NH4-natrolite to explain its thermal stability in better way.
{"title":"Synthesis and structural studies of ammonium exchanged synthetic analogue of disordered aluminosilicate natrolite","authors":"Manjusha J. Gavhane , R.K. Jha , Kyung-Wan Nam , Deu S. Bhange","doi":"10.1016/j.micromeso.2024.113441","DOIUrl":"10.1016/j.micromeso.2024.113441","url":null,"abstract":"<div><div>The current article reports preparation and structural analysis of NH<sub>4</sub><sup>+</sup> exchanged form of synthetic natrolite zeolite (NH<sub>4</sub>-natrolite) with disordered structure wherein Si and Al occupies all the tetrahedral (T) sites in the zeolite framework. Structural data is used to gain insight into the structural parameters those influence thermal stability of its proposed H-form. NH<sub>4</sub>-natrolite is prepared by ion-exchange method from K-natrolite (which was also obtained by ion-exchange with Na-natrolite). Na-natrolite, K-natrolite and NH<sub>4</sub>-natrolite prepared in this study were tested for their structural, morphological and thermal analysis. Synchrotron X-ray diffraction data was utilized to estimate the crystal structures of hydrated forms of Na-natrolite, K-natrolite and NH<sub>4</sub>-exchanged natrolites. Thermal analysis of NH<sub>4</sub>-natrolite revealed that the dehydration is followed by removal of ammonia during calcination. The role of the size (radius) and nature (either divalent or monovalent) of the exchangeable cations present in the channels, the framework chemical content and extent of ‘T’ atom ordering have been collectively discussed and correlated with the structural behaviour of calcined NH<sub>4</sub>-natrolite to explain its thermal stability in better way.</div></div>","PeriodicalId":392,"journal":{"name":"Microporous and Mesoporous Materials","volume":"384 ","pages":"Article 113441"},"PeriodicalIF":4.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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