Heteropoly acid-loaded ionic liquid@metal-organic frameworks: Effective and reusable adsorbents for the desulfurization of a liquid model fuel

Khan, Nazmul Abedin,Bhadra, Biswa Nath,Jhung, Sung Hwa Elsevier 2018 Chemical Engineering Journal Vol.334 No.-

<P><B>Abstract</B></P> <P>An ionic liquid (IL) and a heteropoly acid (HPA) were sequentially incorporated to highly porous metal-organic frameworks (MOFs, ZIF-8 and MIL-100(Fe)) under mild conditions. The IL was synthesized from 1-methylimidazole and 1-bromobutane inside the pore structure of the MOFs via the ship-in-bottle (SIB) technique. Then, the HPA (here, phosphotungstic acid) was incorporated to IL@MOF, where the imidazolium cations play an essential role in anchoring the PA anions to form stable MOF adsorbents bearing IL and HPA. The efficiency of the tri-component adsorbents was evaluated for the adsorptive removal of thiophenics (benzothiophene (BT) and dibenzothiophene (DBT)) from liquid fuel. The BT or DBT adsorption capacity (<I>Q</I> <SUB>0</SUB>) of the modified MOFs was 1.3–1.6 and 2.0–2.5 times to that of the pristine MOFs based on the unit weight and unit surface area of the adsorbents, respectively. The increased <I>Q</I> <SUB>0</SUB> could be explained by the synergistic affinity of IL and HPA species toward thiophenics. Moreover, the adsorbent could be reused for up to four cycles with little loss of BT adsorption capacity, indicating the stability (no leaching) of the HPA and IL within the porous MOFs. From this study, it can be concluded that HPA can be supported on IL@MOF via chemical interactions, affording stable tri-component adsorbents that can be applied to a variety of liquid phase adsorption processes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> HPA/IL@MOF composites were prepared via a novel method. </LI> <LI> The composite showed remarkable performances in adsorptive desulfurization. </LI> <LI> The adsorbent showed stable reusability, different from HPA-loaded MOFs. </LI> <LI> The adsorbent was also very selective to SCCs (compared with aromatics). </LI> <LI> The reason of stable recyclability and selectivity (to SCCs) was also suggested. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Polyaniline-Encapsulated Metal-Organic Framework MIL-101: Adsorbent with Record-High Adsorption Capacity for the Removal of Both Basic Quinoline and Neutral Indole from Liquid Fuel

Khan, Nazmul Abedin,Yoo, Dong Kyu,Jhung, Sung Hwa American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.41

<P>Polyaniline-encapsulated metal-organic frameworks (MOFs; MIL-101, Cr-benzenedicarboxylate) were prepared via a ship-in-bottle strategy and applied in liquid phase adsorptions. The modified MIL-101s showed record-high adsorptions for both basic and neutral nitrogen-containing compounds (NCCs) from liquid model fuel. For example, the maximum adsorption capacities (<I>Q</I><SUB>o</SUB>) of the protonated polyaniline (pANI)@MIL-101 for the basic quinoline and neutral indole from <I>n</I>-octane were 556 and 602 mg/g, respectively. The plausible adsorption mechanisms such as hydrogen bonding, acid-base interaction, and cation−π interaction were proposed to explain the extraordinary adsorptions of the studied adsorbates. Moreover, the adsorbents could be recycled via a simple approach and reused in adsorptions without noticeable decrease in performances. Therefore, the pANI-encapsulated MOFs could be recommended as a new type of adsorbents for very efficient removal of both basic and neutral NCCs from liquid fuel.</P> [FIG OMISSION]</BR>

Scandium-Triflate/Metal–Organic Frameworks: Remarkable Adsorbents for Desulfurization and Denitrogenation

Khan, Nazmul Abedin,Jhung, Sung Hwa American Chemical Society 2015 Inorganic Chemistry Vol.54 No.23

<P>Scandium-triflate (Sc(OTF)(3)) was introduced for the first time on metal organic frameworks (MOFs), to utilize acidic Sc(OTF)(3) for adsorptive desulfurization and denitrogenation of fuel containing benzothiophene (BT), dibenzothiophene (DBT), quinoline (QUI), and indole (IND). A remarkable improvement in the adsorption capacity (about 65% based on the weight of adsorbents; 90% based on the surface area of the adsorbents) was observed with the Sc(OTf)(3)/MOFs as compared to the virgin MOFs for the adsorption of BT from liquid fuel. The basic QUI was also adsorbed preferentially onto the acidic Sc(OTf)(3)/MOFs. However, nonsupported Sc(OTf)(3) showed negligible adsorption capacities. The improved adsorptive performance for BT, DBT, and QUI might be derived from acid base interactions between the acidic Sc(OTf)(3), and basic adsorbates. On the other hand, the Sc(OTf)(3), loaded on MOFs, reduced the adsorption capacity for neutral IND due to lack of interaction between the neutral adsorbate and acidic adsorbent and the reduced porosities of the modified adsorbents. The reusability of the adsorbents was found satisfactory up to the fourth run. On the basis of the result, it is suggested that metal-triflates, such as Sc(OTf)(3), can be prospective materials for adsorptive desulfurization/denitrogenation of fuels when supported on porous materials such as MOFs.</P>

Remarkable Adsorption Capacity of CuCl₂‐Loaded Porous Vanadium Benzenedicarboxylate for Benzothiophene

Khan, Nazmul Abedin,Jhung, Sung Hwa WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.5

<P><B>Ein molekulares Sieb</B>: Ein mit CuCl<SUB>2</SUB> beladenes Metall‐organisches Gerüstmaterial (MOF), MIL‐47, zeigte die höchste Adsorptionskapazität für Benzothiophen. Grund ist das Vorliegen von Cu<SUP>I</SUP>‐Ionen, die durch die Reduktion von Cu<SUP>II</SUP>‐ mit V<SUP>III</SUP>‐Ionen in MIL‐47 entstehen. Das modifizierte MOF konnte erfolgreich zur Entschwefelung eines flüssigen Brennstoffs verwendet werden (siehe Bild).</P>

Remarkable adsorptive performance of a metal–organic framework, vanadium-benzenedicarboxylate (MIL-47), for benzothiophene

Khan, Nazmul Abedin,Jun, Jong Won,Jeong, Jong Hwa,Jhung, Sung Hwa Royal Society of Chemistry 2011 Chemical communications Vol.47 No.4

<P>Liquid-phase adsorption of benzothiophene over isotypic MOFs such as MIL-47 and MIL-53(Al, Cr) has shown that a metal ion of a MOF-type material has a dominant role in adsorptive desulfurization and MIL-47 has a remarkable performance.</P> <P>Graphic Abstract</P><P>A MOF (V-BDC) shows remarkable performance in adsorptive desulfurization, suggesting the importance of a specific adsorption site like an acidic site. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cc04759g'> </P>

Rapid syntheses of a metal–organic framework material Cu₃(BTC)₂(H₂O)₃ under microwave: a quantitative analysis of accelerated syntheses

Khan, Nazmul Abedin,Haque, Enamul,Jhung, Sung Hwa Royal Society of Chemistry 2010 Physical chemistry chemical physics Vol.12 No.11

<P>A typical MOF material, Cu-BTC has been synthesized with microwave and conventional electric heating in various conditions to elucidate, for the first time, the quantitative acceleration in the synthesis of a MOF by microwaves. The acceleration by microwaves is mainly due to rapid nucleation rather than rapid crystal growth, even though both stages are accelerated. The acceleration in the nucleation stage by microwaves is due to the very large pre-exponential factor (about 1.4 × 10<SUP>10</SUP> times that of conventional synthesis) in the Arrhenius plot. However, the activation energy for the nucleation in the case of microwave synthesis is higher than the activation energy of conventional synthesis. The large acceleration in the nucleation, compared with that in the crystal growth, is observed once again by the syntheses in two-steps (changing heating methods from microwave into conventional heating or from conventional heating into microwave heating just after the nucleation is completed). The crystal size of Cu-BTC obtained by microwave-nucleation is generally smaller than the Cu-BTC made by conventional-nucleation, probably due to rapid nucleation and the small size of nuclei with microwave-nucleation.</P> <P>Graphic Abstract</P><P>The accelerated synthesis of Cu-BTC under microwave is mainly due to the acceleration in nucleation and the increased pre-exponential factor. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b921558a'> </P>

Effect of Water Concentration and Acidity on the Synthesis of Porous Chromium Benzenedicarboxylates

Khan, Nazmul Abedin,Jun, Jong Won,Jhung, Sung Hwa WILEY-VCH Verlag 2010 European journal of inorganic chemistry Vol.2010 No.7

<P>In the present work, two metal–organic frameworks (MOFs), chromium benzenedicarboxylates MIL-53 and MIL-101, have been synthesized. A wide range of reaction conditions were explored in order to understand the effects of water concentration and acidity. It was found that MIL-101 is preferentially obtained when the water content is high and the acidity is low. On the contrary, concentrated reactants and high acidity lead to the formation of MIL-53. The steady conversion of MIL-101 into MIL-53 during the reaction, due to the difference in relative stability, was also confirmed. The effect of water may therefore be explained by the increase in reaction rate with increasing concentration of reactants. The MIL-53 is selectively obtained at low water content, because the MIL-101, a transient phase, even if formed initially, may be converted into MIL-53 because of the high reaction rate. Relatively low acidity (a pH of about 3) is beneficial to the synthesis of MIL-101 even though increased MIL-53 yield was expected at low acidity due to the accelerated deprotonation of terephthalic acid. The selective formation of MIL-101 at low acidity is probably because the concentration of a chromium trimer (the chromium species that is essential for the MIL-101 structure) increases with increasing pH. The concentration of the Cr trimer is more important than the concentration of benzenedicarboxylate for the synthesis of MIL-101.</P> <B>Graphic Abstract</B> <P>Two chromium benzenedicarboxylates (MIL-101 and MIL-53) were synthesized, and the reaction conditions were optimized. MIL-101 is obtained preferentially in dilute solution and at low acidity, because the concentration of the Cr trimer is moreimportant than the concentration of benzenedicarboxylate. On the contrary, MIL-53 is produced in concentrated solution at low pH, because of the rapid reaction. <img src='wiley_img_2010/14341948-2010-2010-7-EJIC200901064-fig000.gif' alt='wiley_img_2010/14341948-2010-2010-7-EJIC200901064-fig000'> </P>

Phytic acid-encapsulated MIL-101(Cr): Remarkable adsorbent for the removal of both neutral indole and basic quinoline from model liquid fuel

Khan, Nazmul Abedin,Jhung, Sung Hwa Elsevier 2019 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.375 No.-

<P><B>Abstract</B></P> <P>Phytic acid (PA) encapsulated metal-organic framework (MIL-101(Cr) or Cr-benzenedicarboxylate) was prepared for the first time; and applied in the adsorptive removal of nitrogen-containing compounds (NCCs) from liquid model fuel. The modified MIL-101(Cr)s resulted in very promising maximum adsorption capacities (<I>Q</I> <SUB>0</SUB>) for both the neutral indole (IND, <I>Q</I> <SUB>0</SUB> = 543 mg/g) and basic quinoline (QUI, <I>Q</I> <SUB>0</SUB> = 549 mg/g) compared to the pristine MIL-101(Cr) (IND; <I>Q</I> <SUB>0</SUB> = 416 mg/g; QUI, <I>Q</I> <SUB>0</SUB> = 409 mg/g). Or, the <I>Q</I> <SUB>o</SUB> values of PA(3)@MIL-101(Cr) for the adsorptions of IND and QUI stand at the second and fifth positions, respectively, among any previously reported results. Moreover, the new adsorbent showed around 8 times adsorption capacity to that of conventional activated carbon. PA encapsulation onto MIL-101(Cr) resulted in 86% and 91% increased adsorption (based on unit surface area of adsorbent) of IND and QUI, respectively. Moreover, PA(3)@MIL-101(Cr) showed more effective/selective adsorption than pristine MIL-101(Cr) towards the NCCs especially when toluene (as aromatics) was added as co-solvent. The extraordinary adsorptions could be described by the hydrogen bonding and the acid-base interactions between the NCCs and the PA functionalities of the adsorbents. Moreover, the PA@MIL-101(Cr)s could be regenerated via a simple manner and reused in adsorptions up to several cycles. Therefore, the novel PA@MOF materials could be suggested as a type of very efficient adsorbents for the adsorptive removal of both neutral and basic NCCs from liquid model fuel.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Phytic acid (PA) was loaded onto a MOF to get novel adsorbent for fuel purification. </LI> <LI> PA@MOF had ~8 times adsorption for indole and quinoline to that of activated carbon. </LI> <LI> PA@MOF showed more effective adsorption than MOF when aromatics co-present. </LI> <LI> More effective adsorption could be explained via H-bonding and acid-base interaction. </LI> <LI> PA@MOF could be regenerated via solvent washing and reused up to several cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Liquid-phase Dehydration of 1-Phenylethanol to Styrene over an Acidic Resin Catalyst

Khan, Nazmul Abedin,Hwang, Jin-Soo,Jhung, Sung-Hwa Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.4

Dehydration of 1-phenylethanol to produce styrene has been studied in liquid phase with three solid acid catalysts such as H-ZSM-5, H-Y and Amberlyst-15. Amberlyst-15 shows the highest conversion and styrene yield, suggesting the applicability of a resin catalyst in the dehydration. The good performance of the Amberlyst-15 may be due to high acid concentration and ready diffusion of reactants and products. A possible reaction scheme (such as the formation of styrene from diphenylethylether) has also been suggested.

Facile Syntheses of Metal-organic Framework Cu3(BTC)2(H2O)3 under Ultrasound

Nazmul Abedin Khan,정성화 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.12

Cu-BTC[Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzenetricarboxylate], one of the most well-known metal-organic framework materials (MOF), has been synthesized under atmospheric pressure and room temperature by using ultrasound. The Cu-BTC can be obtained in 1 min in the presence of DMF (N,N-dimethylformamide), suggesting the possibility of continuous production of Cu-BTC. Moreover, the surface area and pore volume show that the concentration of DMF is important for the synthesis of Cu-BTC having high porosity. The morphology and phase also depend on the concentration of DMF : Cu-BTC cannot be obtained at room temperature in the absence of DMF and aggregated Cu-BTC (with low surface area) is produced in the presence of high concentration of DMF. It seems that the deprotonation of benzenetricarboxylic acid by base (such as DMF) is inevitable for the room temperature syntheses.