Disulfide-linked covalent organic polymers (COPs) were prepared through catalyst-free oxidative coupling polymerization. Owing to the excellent swelling behavior, low cost, and efficient synthesis, these materials can be promising materials for removal of organics in concentrated streams. COPs show 1,4-dioxane uptake up to 1.8 g g−1.
Showing posts with label KAIST. Show all posts
Showing posts with label KAIST. Show all posts
Nanoporous covalent organic polymers incorporating Tröger’s base functionalities for enhanced CO2 capture
J. Byun, S. H. Je, H. A. Patel, A. Coskun,* C. T. Yavuz*
J. Mater. Chem. A, 2, 12507-12512, 2014. [DOI] [pdf] [WoS]
The CO2 uptake capacity and CO2/N2 selectivity of Tröger’s base–bridged nanoporous covalent organic polymers (TB-COPs) were investigated. TB-COPs were synthesized by reacting amine terminals of tetrahedral monomers - namely, tetraanilyladamantane and tetraanilylmethane - with dimethoxymethane in a one–pot reaction under relatively mild conditions. Interestingly, these two tetrahedral monomers formed nanoporous polymers with substantially different surface areas. While the trögerization of tetraanilyladamantane monomer (TB-COP-1) exhibit high surface area of 1340 m2 g-1, that of tetraanilylmethane monomer (TB-COP-2) is found to be only 0.094 m2 g-1. This unusual phenomenon can be explained by the proximity of amino moieties to each other within the monomeric unit. Shorter distance between the amino groups enables intramolecular cyclization along with the intermolecular one, thus resulting in much lower porosity. TB-COP-1 exhibits significant CO2 uptakes up to 5.19 and 3.16 mmol g-1 at 273 and 298K under ambient pressure, and CO2/N2 selectivities of 79.2 and 68.9 at 273 and 298K at 1 bar for the gas mixture of CO2:N2 in the ratio of 0.15:0.85. It is noteworthy that TB-COP-1 showed remarkable selectivity retention with rising temperature from 273 to 298 K.
J. Mater. Chem. A, 2, 12507-12512, 2014. [DOI] [pdf] [WoS]
The CO2 uptake capacity and CO2/N2 selectivity of Tröger’s base–bridged nanoporous covalent organic polymers (TB-COPs) were investigated. TB-COPs were synthesized by reacting amine terminals of tetrahedral monomers - namely, tetraanilyladamantane and tetraanilylmethane - with dimethoxymethane in a one–pot reaction under relatively mild conditions. Interestingly, these two tetrahedral monomers formed nanoporous polymers with substantially different surface areas. While the trögerization of tetraanilyladamantane monomer (TB-COP-1) exhibit high surface area of 1340 m2 g-1, that of tetraanilylmethane monomer (TB-COP-2) is found to be only 0.094 m2 g-1. This unusual phenomenon can be explained by the proximity of amino moieties to each other within the monomeric unit. Shorter distance between the amino groups enables intramolecular cyclization along with the intermolecular one, thus resulting in much lower porosity. TB-COP-1 exhibits significant CO2 uptakes up to 5.19 and 3.16 mmol g-1 at 273 and 298K under ambient pressure, and CO2/N2 selectivities of 79.2 and 68.9 at 273 and 298K at 1 bar for the gas mixture of CO2:N2 in the ratio of 0.15:0.85. It is noteworthy that TB-COP-1 showed remarkable selectivity retention with rising temperature from 273 to 298 K.
Directing the Structural Features of N2-Phobic Nanoporous Covalent Organic Polymers for CO2 Capture and Separation
H. A. Patel, S. H. Je, J. Park, Y. Jung, A. Coskun*, C. T. Yavuz*
Chem. Eur. J., 20, 772-780, (2014). [DOI] [pdf] [WOS]
Chem. Eur. J., 20, 772-780, (2014). [DOI] [pdf] [WOS]
A family of azo-bridged covalent organic polymers (azo-COPs) was synthesized through a catalyst-free direct coupling of aromatic nitro and amine compounds under basic conditions. The azo-COPs formed 3D nanoporous networks and exhibited surface areas up to 729.6 m2 g−1, with a CO2-uptake capacity as high as 2.55 mmol g−1 at 273 K and 1 bar. Azo-COPs showed remarkable CO2/N2 selectivities (95.6–165.2) at 298 K and 1 bar. Unlike any other porous material, CO2/N2 selectivities of azo-COPs increase with rising temperature. It was found that azo-COPs show less than expected affinity towards N2 gas, thus making the framework “N2-phobic”, in relative terms. Our theoretical simulations indicate that the origin of this unusual behavior is associated with the larger entropic loss of N2 gas molecules upon their interaction with azo-groups. The effect of fused aromatic rings on the CO2/N2 selectivity in azo-COPs is also demonstrated. Increasing the π-surface area resulted in an increase in the CO2-philic nature of the framework, thus allowing us to reach a CO2/N2 selectivity value of 307.7 at 323 K and 1 bar, which is the highest value reported to date. Hence, it is possible to combine the concepts of “CO2-philicity” and “N2-phobicity” for efficient CO2 capture and separation. Isosteric heats of CO2 adsorption for azo-COPs range from 24.8–32.1 kJ mol−1 at ambient pressure. Azo-COPs are stable up to 350 °C in air and boiling water for a week. A promising cis/trans isomerization of azo-COPs for switchable porosity is also demonstrated, making way for a gated CO2 uptake.
Amidoxime Porous Polymers for CO2 Capture
S. Zulfiqar, S. Awan, F. Karadas, M. Atilhan*, C. T. Yavuz*, M. I. Sarwar*
RSC Adv., 3 (38), 17203 - 17213, (2013). [DOI] [pdf] [WOS]
CO2 capture from fossil fuel based electricity generation remains unchallenged since new power plants with monoethanol amine (MEA) as the scrubbing agent are under construction. Amidoximes are known to mimic MEA and porous polymers with amidoximes could offer a sustainable solution to carbon capture. Here we report the first amidoxime porous polymers (APPs) where aromatic polyamides (aramids) having amidoxime pendant groups were synthesized through low temperature condensation of 4,4′-oxydianiline (ODA) and p-phenylene diamine (p-PDA) with a new type of nitrile-bearing aromatic diacid chloride. The nitrile pendant groups of the polyamides were converted into amidoxime functionality by a rapid hydroxylamine addition (APP-1 and APP-2). The CO2 adsorption capacities of these polyamides were measured at low pressure (1 bar) and two different temperatures (273 and 298 K) and high pressure (up to 225 bar – highest measuring pressure to date) at 318 K. The low pressure CO2 uptake of APP-1 was found to be 0.32 mmol/g compared to APP-2 (0.07 mmol/g) at 273 K, whereas at high pressure they showed a substantial increase in CO2 adsorption capacity exhibiting 24.69 and 11.67 mmol/g for APP-1 and APP-2 respectively. Both aramids were found to be solution processible, enabling membrane applications.
RSC Adv., 3 (38), 17203 - 17213, (2013). [DOI] [pdf] [WOS]
CO2 capture from fossil fuel based electricity generation remains unchallenged since new power plants with monoethanol amine (MEA) as the scrubbing agent are under construction. Amidoximes are known to mimic MEA and porous polymers with amidoximes could offer a sustainable solution to carbon capture. Here we report the first amidoxime porous polymers (APPs) where aromatic polyamides (aramids) having amidoxime pendant groups were synthesized through low temperature condensation of 4,4′-oxydianiline (ODA) and p-phenylene diamine (p-PDA) with a new type of nitrile-bearing aromatic diacid chloride. The nitrile pendant groups of the polyamides were converted into amidoxime functionality by a rapid hydroxylamine addition (APP-1 and APP-2). The CO2 adsorption capacities of these polyamides were measured at low pressure (1 bar) and two different temperatures (273 and 298 K) and high pressure (up to 225 bar – highest measuring pressure to date) at 318 K. The low pressure CO2 uptake of APP-1 was found to be 0.32 mmol/g compared to APP-2 (0.07 mmol/g) at 273 K, whereas at high pressure they showed a substantial increase in CO2 adsorption capacity exhibiting 24.69 and 11.67 mmol/g for APP-1 and APP-2 respectively. Both aramids were found to be solution processible, enabling membrane applications.
Limitations and high pressure behavior of MOF-5 for CO2 capture
J. Y. Jung,‡ F. Karadas,‡ S. Zulfiqar,‡ E. Deniz, S. Aparicio, M. Atilhan*, C. T. Yavuz*, S. M. Han*
Phys. Chem. Chem. Phys., 15, 14319-14327, (2013). [pdf] [DOI] [WOS] (‡ Equal contribution)
Phys. Chem. Chem. Phys., 15, 14319-14327, (2013). [pdf] [DOI] [WOS] (‡ Equal contribution)
Porous network structures (e.g. metal organic frameworks, MOFs) show considerable potential in dethroning monoethanol amine (MEA) from being the dominant scrubber for CO2 at the fossil-fuel-burning power generators. Contrary to their promise, structural stability and high-pressure behavior of MOFs are not well documented. We herein report moisture stability, mechanical properties and high-pressure compression on a model MOF structure, MOF-5. Our results show that MOF-5 can endure all tested pressures (0-225 bar) without losing its structural integrity, however, its moist air stability points at a 3.5-hour safety window (at 21.6 oC and 49% humidity) for an efficient CO2 capture. Isosteric heats of CO2 adsorption at high pressures show moderate interaction energy between CO2 molecules and MOF-5 sorbent, which combined with the MOF-5 large sorption ability in the studied pressure – temperature ranges show the viability of this sorbent for CO2 capturing purposes. The combination of the physicochemical methods we used suggests a generalized analytical standard for measuring viability in CO2 capture operations.
Influence of aminosilane coupling agent on aromatic polyamide/intercalated clay nanocomposites
M. U. Alvi, S. Zulfiqar*, C. T. Yavuz, H.-S. Kweon, M. I. Sarwar*
Ind. Eng. Chem. Res., 52 (21), 6908–6915, (2013). [DOI] [pdf] [WOS]
Aminosilane grafted and 1,4-phenylene diamine modified reactive montmorillonite was exploited for the generation of aromatic polyamide-layered silicate nanocomposites. For better compatibility between the two disparate phases, the hydrophilic nature of montmorillonite was changed into organophilic by ion-exchange method using 1,4-phenylenediamine as an intercalating agent and the hydroxyl groups present on clay surface and edges were used to graft 3-aminopropyltriethoxysilane (APTS) on clay platelets. The dispersion behavior of reactive organoclay was monitored in the polyamide matrix prepared from a pair of diamines (1,4-phenylenediamine and 4-4′-oxydianiline) with isophthaloyl chloride under anhydrous conditions. The resulting chains were selectively converted into carbonyl chloride ends to interact exclusively with free amine groups of the 1,4-phenylenediamine and APTS grafted on nanoclay. Thin composite films containing 2 to 10-wt. % clay were probed for FTIR, XRD, SEM, TEM, tensile testing, TGA and DSC measurements. XRD and TEM results described ample dispersion and morphology of clay sheets in the nanocomposites. Mechanical measurements revealed that tensile strength increased 110 %, elongation 172 % while modulus and toughness augmented many folds upon the addition of 4-6 wt. % clay in the matrix. Thermal decomposition temperatures of the nanocomposites were in the range 425-480 oC. The glass transition temperature increased up to 142.4 oC with 6-wt. % addition of organoclay in the matrix relative to pure polyamide depicting interfacial interactions among the phases.
Ind. Eng. Chem. Res., 52 (21), 6908–6915, (2013). [DOI] [pdf] [WOS]
Aminosilane grafted and 1,4-phenylene diamine modified reactive montmorillonite was exploited for the generation of aromatic polyamide-layered silicate nanocomposites. For better compatibility between the two disparate phases, the hydrophilic nature of montmorillonite was changed into organophilic by ion-exchange method using 1,4-phenylenediamine as an intercalating agent and the hydroxyl groups present on clay surface and edges were used to graft 3-aminopropyltriethoxysilane (APTS) on clay platelets. The dispersion behavior of reactive organoclay was monitored in the polyamide matrix prepared from a pair of diamines (1,4-phenylenediamine and 4-4′-oxydianiline) with isophthaloyl chloride under anhydrous conditions. The resulting chains were selectively converted into carbonyl chloride ends to interact exclusively with free amine groups of the 1,4-phenylenediamine and APTS grafted on nanoclay. Thin composite films containing 2 to 10-wt. % clay were probed for FTIR, XRD, SEM, TEM, tensile testing, TGA and DSC measurements. XRD and TEM results described ample dispersion and morphology of clay sheets in the nanocomposites. Mechanical measurements revealed that tensile strength increased 110 %, elongation 172 % while modulus and toughness augmented many folds upon the addition of 4-6 wt. % clay in the matrix. Thermal decomposition temperatures of the nanocomposites were in the range 425-480 oC. The glass transition temperature increased up to 142.4 oC with 6-wt. % addition of organoclay in the matrix relative to pure polyamide depicting interfacial interactions among the phases.
Phosphorus stimulated unidirectional growth of TiO2 nanostructures
L. White, M. Kim, J. Zhang, S. Kraemer, C. T. Yavuz, M. Moskovits, A. M. Wodtke, G. D. Stucky*
J. Mater. Chem. A, 1, 6091-6098, (2013). [DOI] [pdf] [WOS]
Previously reported TiO2 nanowire fabrication from Ni catalysts shows a surprising amount of phosphorous (P) contamination incorporated into the seed particle. We proposed this unintentional P-doping of Ni particles aids the mechanism for nanowire growth and occurs by an alternative pathway from the Vapor–Liquid–Solid (VLS) mechanism. To confirm this new mechanism, mixed phase NiP/Ni2P (NixPy) and Ni2P nanoparticles were fabricated and the central role of phosphorous in TiO2 nanowire synthesis confirmed. This newly developed P-assisted fabrication method yielded crystalline rutile TiO2 nanowires. In this mechanism solid, quasi-spherical catalyst particles attached to the ends of nanowires and surrounded by a Ni/P liquid shell are responsible for the nanowire growth. The growing end of the nanowire appears to form a “tangent-plane” to the solid catalyst core with the liquid shell wetting and occupying the interstice between the catalyst and the nanowire. In NixPy assisted growth, nanowire diameters occurred as small as 12.3 nm, some of the thinnest yet reported TiO2 nanowires resulting from atmospheric-pressure chemical vapor deposition (APCVD) growth.
J. Mater. Chem. A, 1, 6091-6098, (2013). [DOI] [pdf] [WOS]
Previously reported TiO2 nanowire fabrication from Ni catalysts shows a surprising amount of phosphorous (P) contamination incorporated into the seed particle. We proposed this unintentional P-doping of Ni particles aids the mechanism for nanowire growth and occurs by an alternative pathway from the Vapor–Liquid–Solid (VLS) mechanism. To confirm this new mechanism, mixed phase NiP/Ni2P (NixPy) and Ni2P nanoparticles were fabricated and the central role of phosphorous in TiO2 nanowire synthesis confirmed. This newly developed P-assisted fabrication method yielded crystalline rutile TiO2 nanowires. In this mechanism solid, quasi-spherical catalyst particles attached to the ends of nanowires and surrounded by a Ni/P liquid shell are responsible for the nanowire growth. The growing end of the nanowire appears to form a “tangent-plane” to the solid catalyst core with the liquid shell wetting and occupying the interstice between the catalyst and the nanowire. In NixPy assisted growth, nanowire diameters occurred as small as 12.3 nm, some of the thinnest yet reported TiO2 nanowires resulting from atmospheric-pressure chemical vapor deposition (APCVD) growth.
A combined computational and experimental study of high pressure and supercritical CO2 adsorption on Basolite MOFs
E. Deniz, F. Karadas, H. A. Patel, S. Aparicio*, C. T. Yavuz*, M. Atilhan*
Micropor. Mesopor. Mat., 175, 34-42 (2013). [DOI] [pdf] [WOS]
Metal organic frameworks (such as commercial Basolite®) display significant promise for CO2 capture and storage. Here, in order to monitor CO2 capture of Basolite®, we combined high pressure CO2 adsorption with high-pressure FTIR and Monte Carlo simulations. We found that Basolite® C300 show an unprecedented rise in capture capacity above 25 bars, as predicted by the DFT calculations. Adsorption isotherms were measured up to 200 bar using a state-of-the-art magnetic suspension balance, and in-situ FTIR studies as a function of pressure allowed characterizing the preferential adsorption sites, and their occupancy with increasing pressure. Monte Carlo molecular simulations were used to infer nanoscopic information of the adsorption mechanism, showing the sorbent–CO2 interactions from structural and energetic viewpoints.
Click here to access via the publisher
Micropor. Mesopor. Mat., 175, 34-42 (2013). [DOI] [pdf] [WOS]
Metal organic frameworks (such as commercial Basolite®) display significant promise for CO2 capture and storage. Here, in order to monitor CO2 capture of Basolite®, we combined high pressure CO2 adsorption with high-pressure FTIR and Monte Carlo simulations. We found that Basolite® C300 show an unprecedented rise in capture capacity above 25 bars, as predicted by the DFT calculations. Adsorption isotherms were measured up to 200 bar using a state-of-the-art magnetic suspension balance, and in-situ FTIR studies as a function of pressure allowed characterizing the preferential adsorption sites, and their occupancy with increasing pressure. Monte Carlo molecular simulations were used to infer nanoscopic information of the adsorption mechanism, showing the sorbent–CO2 interactions from structural and energetic viewpoints.
Click here to access via the publisher
Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers
H. A. Patel, S. H. Je, J. Park, D. P. Chen, Y. Jung, C. T. Yavuz*, A. Coskun*
Nature Commun., 4, 1357, (2013). [DOI] [pdf] [WOS]
Post-combustion CO2 capture and air separation are integral parts of the energy industry, although the available technologies remain inefficient, resulting in costly energy penalties. Here we report azo-bridged, nitrogen-rich, aromatic, water stable, nanoporous covalent organic polymers, which can be synthesized by catalyst-free direct coupling of aromatic nitro and amine moieties under basic conditions. Unlike other porous materials, azo-covalent organic polymers exhibit an unprecedented increase in CO2/N2 selectivity with increasing temperature, reaching the highest value (288 at 323 K) reported to date. Here we observe that azo groups reject N2, thus making the framework N2-phobic. Monte Carlo simulations suggest that the origin of the N2 phobicity of the azo-group is the entropic loss of N2 gas molecules upon binding, although the adsorption is enthalpically favourable. Any gas separations that require the efficient exclusion of N2gas would do well to employ azo units in the sorbent chemistry.
Nature Commun., 4, 1357, (2013). [DOI] [pdf] [WOS]
With CO2/N2 selectivity of 288, Azo-COP-2 (COP-69) holds the current world record
Highlighted in Chemical & Engineering News, Chemistry World, Yeni Asir (Turkish)(another link), Aktif Haber (Turkish), Zaman (Turkish), Bugun (Turkish), Enerji Enstitusu (Turkish), Daejeon Ilbo (Korean), MK News (Korean), Yonhap News (Korean)
Highlighted in Chemical & Engineering News, Chemistry World, Yeni Asir (Turkish)(another link), Aktif Haber (Turkish), Zaman (Turkish), Bugun (Turkish), Enerji Enstitusu (Turkish), Daejeon Ilbo (Korean), MK News (Korean), Yonhap News (Korean)
Post-combustion CO2 capture and air separation are integral parts of the energy industry, although the available technologies remain inefficient, resulting in costly energy penalties. Here we report azo-bridged, nitrogen-rich, aromatic, water stable, nanoporous covalent organic polymers, which can be synthesized by catalyst-free direct coupling of aromatic nitro and amine moieties under basic conditions. Unlike other porous materials, azo-covalent organic polymers exhibit an unprecedented increase in CO2/N2 selectivity with increasing temperature, reaching the highest value (288 at 323 K) reported to date. Here we observe that azo groups reject N2, thus making the framework N2-phobic. Monte Carlo simulations suggest that the origin of the N2 phobicity of the azo-group is the entropic loss of N2 gas molecules upon binding, although the adsorption is enthalpically favourable. Any gas separations that require the efficient exclusion of N2gas would do well to employ azo units in the sorbent chemistry.
Highly Stable Nanoporous Sulfur bridged Covalent Organic Polymers for Carbon Dioxide Removal
H. A. Patel, F. Karadas, J. Byun, J. Park, E. Deniz, A. Canlier, Y. Jung,* M. Atilhan*, C. T. Yavuz*
Adv. Funct. Mater., 23, 2270–2276 (2013). [DOI] [pdf]
Carbon dioxide capture and separation requires robust solids that can stand harsh environments where a hot mixture of gases is often found. Herein, the first and comprehensive syntheses of porous sulfur-bridged covalent organic polymers (COPs) and their application for carbon dioxide capture in warm conditions and a wide range of pressures (0–200 bar) are reported. These COPs can store up to 3294 mg g−1 of carbon dioxide at 318 K and 200 bar while being highly stable against heating up to 400 °C. The carbon dioxide capacity of the COPs is also not hindered upon boiling in water for at least one week. Physisorptive binding is prevalent with isosteric heat of adsorptions around 24 kJ mol−1. M06–2X and RIMP2 calculations yield the same relative trend of binding energies, where, interestingly, the dimer of triazine and benzene play a cooperative role for a stronger binding of CO2 (19.2 kJ mol−1) as compared to a separate binding with triazine (13.3 kJ mol−1) or benzene (11.8 kJ mol−1).
Click here for the supporting information
Adv. Funct. Mater., 23, 2270–2276 (2013). [DOI] [pdf]
Carbon dioxide capture and separation requires robust solids that can stand harsh environments where a hot mixture of gases is often found. Herein, the first and comprehensive syntheses of porous sulfur-bridged covalent organic polymers (COPs) and their application for carbon dioxide capture in warm conditions and a wide range of pressures (0–200 bar) are reported. These COPs can store up to 3294 mg g−1 of carbon dioxide at 318 K and 200 bar while being highly stable against heating up to 400 °C. The carbon dioxide capacity of the COPs is also not hindered upon boiling in water for at least one week. Physisorptive binding is prevalent with isosteric heat of adsorptions around 24 kJ mol−1. M06–2X and RIMP2 calculations yield the same relative trend of binding energies, where, interestingly, the dimer of triazine and benzene play a cooperative role for a stronger binding of CO2 (19.2 kJ mol−1) as compared to a separate binding with triazine (13.3 kJ mol−1) or benzene (11.8 kJ mol−1).
Click here for the supporting information
High Pressure CO2 Absorption Studies on Imidazolium Based Ionic Liquids: Experimental and Simulation Approaches
F. Karadas, B. Köz, J. Jacquemin, E. Deniz, D. Rooney, J. Thompson, C. T. Yavuz, M. Khraisheh, S. Aparicio*, M. Atihan*
Fluid Phase Equilibria, 351, 74–86 (2013). [DOI] [pdf]
A combined experimental–computational study on the CO2 absorption on 1-butyl-3-methylimidazolium hexafluophosphate, 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide, and 1-butyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide ionic liquids is reported. The reported results allowed to infer a detailed nanoscopic vision of the absorption phenomena as a function of pressure and temperature. Absorption isotherms were measured at 318 and 338 K for pressures up to 20 MPa for ultrapure samples using a state-of-the-art magnetic suspension densimeter, for which measurement procedures are developed. A remarkable swelling effect upon CO2 absorption was observed for pressures higher than 10 MPa, which was corrected using a method based on experimental volumetric data. The experimental data reported in this work are in good agreement with available literature isotherms. Soave–Redlich–Kwong and Peng–Robinson equations of state coupled with bi-parametric van der Waals mixing rule were used for successful correlations of experimental high pressure absorption data. Molecular dynamics results allowed to infer structural, energetic and dynamic properties of the studied CO2 + ionic liquids mixed fluids, showing the relevant role of the strength of anion–cation interactions on fluid volumetric properties and CO2 absorption.
Keywords
Ionic liquids; High-pressure; Carbon dioxide; Solubility; Imidazolium; Molecular dynamics
A combined experimental–computational study on the CO2 absorption on 1-butyl-3-methylimidazolium hexafluophosphate, 1-ethyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide, and 1-butyl-3-methylimidazolium bis[trifluoromethylsulfonyl]imide ionic liquids is reported. The reported results allowed to infer a detailed nanoscopic vision of the absorption phenomena as a function of pressure and temperature. Absorption isotherms were measured at 318 and 338 K for pressures up to 20 MPa for ultrapure samples using a state-of-the-art magnetic suspension densimeter, for which measurement procedures are developed. A remarkable swelling effect upon CO2 absorption was observed for pressures higher than 10 MPa, which was corrected using a method based on experimental volumetric data. The experimental data reported in this work are in good agreement with available literature isotherms. Soave–Redlich–Kwong and Peng–Robinson equations of state coupled with bi-parametric van der Waals mixing rule were used for successful correlations of experimental high pressure absorption data. Molecular dynamics results allowed to infer structural, energetic and dynamic properties of the studied CO2 + ionic liquids mixed fluids, showing the relevant role of the strength of anion–cation interactions on fluid volumetric properties and CO2 absorption.
Keywords
Ionic liquids; High-pressure; Carbon dioxide; Solubility; Imidazolium; Molecular dynamics
Noninvasive Functionalization of Polymers of Intrinsic Microporosity for Enhanced CO2 Capture
H. A. Patel, C. T. Yavuz*
Chem. Comm., 48 (80), 9989 - 9991 (2012). [DOI] [pdf]
Modifying sorbents for the purpose of improving carbon dioxide capture often results in the loss of surface area or accessible pores, or both. We report the first noninvasive functionalization of the polymers of intrinsic microporosity (PIMs) where inclusion of amidoxime functionality in PIM-1 increases carbon dioxide capacity up to 17 % and micropore surfaces at 20 % without losing its film forming ability.
Chem. Comm., 48 (80), 9989 - 9991 (2012). [DOI] [pdf]
Modifying sorbents for the purpose of improving carbon dioxide capture often results in the loss of surface area or accessible pores, or both. We report the first noninvasive functionalization of the polymers of intrinsic microporosity (PIMs) where inclusion of amidoxime functionality in PIM-1 increases carbon dioxide capacity up to 17 % and micropore surfaces at 20 % without losing its film forming ability.
Arsenic removal by magnetic nanocrystalline barium hexaferrite
H. A. Patel, J. Byun, C. T. Yavuz*
J. Nanopart. Res., 14 (7), 881 (2012). [DOI] [pdf]
J. Nanopart. Res., 14 (7), 881 (2012). [DOI] [pdf]
Nanoscale magnetite (Fe3O4) (<15 nm) is known to remove arsenic efficiently but is very difficult to separate or require high magnetic fields to separate out from the waste water after treatment. Anisotropic hexagonal ferrite (BaFe12O19, BHF) is a well-known permanent magnet (i.e., fridge magnets) and attractive due to its low cost in making large quantities. BHF offers a viable alternative to magnetite nanocrystals for arsenic removal since it features surfaces similar to iron oxides but with much enhanced magnetism. Herein, we employ BHF nanocrystalline materials for the first time in arsenic removal from wastewater. Our results show better (75 %) arsenic removal than magnetite of the similar sizes. The BHF nanoparticles, 6.06 ± 0.52 nm synthesized by thermolysis method at 320 °C do not show hexagonal phase, however, subsequent annealing at 750 °C produced pure hexagonal BHF in >200 nm assemblies. By using BHF, we demonstrate that nanoparticle removal is more efficient and fixed bed type cartridge applications are more possible.
CO2 Adsorption Studies on Prussian Blue Analogues
F. Karadas, H. El-Faki, E. Deniz, C.T. Yavuz*, S. Aparicio*, M. Atilhan*
Micropor. Mesopor. Mat., 162, 91-97, (2012). [DOI] [pdf] [WOS]
Carbon dioxide (CO2) adsorption capacities of several Prussian Blue (PB) analogues have been studied using the state-of-the-art Rubotherm® sorption apparatus to obtain adsorption and desorption isotherms of these compounds up to 50 bar. The analogues were prepared by simply reacting a [M(CN)6]3- (M= Co, Fe) solution with solutions of M2+ (M= Mn, Fe, Co, Ni, Cu) metal ions. Characterization of the studied samples has been performed by using a combination of powder XRD, TGA, FTIR, and CHN elemental analysis. Adsorption capacities of PB analogues calculated with theoretical calculations, using Monte Carlo approach, have also been compared with the experimental study, and used to discuss the molecular mechanism of adsorption.
Micropor. Mesopor. Mat., 162, 91-97, (2012). [DOI] [pdf] [WOS]
Carbon dioxide (CO2) adsorption capacities of several Prussian Blue (PB) analogues have been studied using the state-of-the-art Rubotherm® sorption apparatus to obtain adsorption and desorption isotherms of these compounds up to 50 bar. The analogues were prepared by simply reacting a [M(CN)6]3- (M= Co, Fe) solution with solutions of M2+ (M= Mn, Fe, Co, Ni, Cu) metal ions. Characterization of the studied samples has been performed by using a combination of powder XRD, TGA, FTIR, and CHN elemental analysis. Adsorption capacities of PB analogues calculated with theoretical calculations, using Monte Carlo approach, have also been compared with the experimental study, and used to discuss the molecular mechanism of adsorption.
One-pot facile synthesis of PEGylated Au nanoparticles in an aqueous media
S. T. Camli, F. Buyukserin, C. T. Yavuz, M. S. Yavuz*
Mater. Chem. Phys., 134 (2–3), 1153–1159, (2012). [DOI] [pdf]
We describe a facile protocol for the synthesis of PEGylated Au nanoparticles by simply mixing aqueous solutions of HAuCl4 and oligo(ethylene glycol) ethyl ether methacrylate. This method was applied to generate uniform multiply-twinned Au nanostructures of ∼21 nm in diameter with high yields. Our proposed mechanism indicates that the generation of primary alcohol intermediates from the nucleophilic addition reaction of water (nucleophile) with AuIII–vinyl complex is responsible for the reduction of gold ions. This protocol was also used to synthesize Ag nanoparticles and small aggregates of Pd nanoparticles. Due to the exclusion of sophisticated synthesis of PEG containing stabilizers, additional surfactants, or reducing agents, this approach provides a remarkably simple, versatile, and environmentally benign protocol to prepare PEGylated noble-metal nanocrystals. A comparative BSA adsorption study proved the lack of non-specific binding, a common obstacle in designing biocompatible nanoparticles.
Mater. Chem. Phys., 134 (2–3), 1153–1159, (2012). [DOI] [pdf]
High capacity carbon dioxide adsorption by inexpensive covalent organic polymers
H. A. Patel, F. Karadas, A. Canlier, J. Park, E. Deniz, Y. Jung, M. Atilhan*, C. T. Yavuz*
J. Mater. Chem., 22, 8431-8437, (2012). [DOI] [pdf]
Abstract:
Top five in CO2 capture capacity*:
1. COP-1: 5616 mg/g
2. MOF-210: 2870 mg/g
3. NU-100: 2315 mg/g
4. PPN-4: 2121 mg/g
5. COP-2: 2086 mg/g
*These capacities reflect the highest recorded values, regardless of the conditions. In addition, according to our recent high pressure data on common solids, we believe the rankings won't change much even if the pressures are raised.
J. Mater. Chem., 22, 8431-8437, (2012). [DOI] [pdf]
With 5616 mg/g, COP-1 sets the new world record for the highest CO2 capture capacity
At infinite selectivity, COP-2 holds the world record in CO2/H2 separation
Abstract:
Efficient CO2 scrubbing without a significant energy penalty remains an outstanding challenge for fossil fuel-burning industry where aqueous amine solutions are still widely used. Porous materials have long been evaluated for next generation CO2 adsorbents. Porous polymers, robust and inexpensive, show promise as feasible materials for the capture of CO2 from warm exhaust fumes. We report the syntheses of porous covalent organic polymers (COPs) with CO2 adsorption capacities of up to 5616 mg/g (measured at high pressures, i.e.200 bar) and industrially relevant temperatures (as warm as 65 oC). COPs are stable in boiling water for at least one week and near infinite CO2/H2selectivity is observed.
Top five in CO2 capture capacity*:
1. COP-1: 5616 mg/g
2. MOF-210: 2870 mg/g
3. NU-100: 2315 mg/g
4. PPN-4: 2121 mg/g
5. COP-2: 2086 mg/g
*These capacities reflect the highest recorded values, regardless of the conditions. In addition, according to our recent high pressure data on common solids, we believe the rankings won't change much even if the pressures are raised.
+ This paper was published as is in 16 days after initial receipt
Amidoximes: Promising Candidates for CO2 Capture
S. Zulfiqar, F. Karadas, J. Park, E. Deniz, G. D. Stucky, Y. Jung*, M. Atilhan*, C. T. Yavuz*
Energy Environ. Sci., 4, 4528-4531, (2011). [DOI] [pdf]
Energy Environ. Sci., 4, 4528-4531, (2011). [DOI] [pdf]
Monoethanolamine (MEA) dominates power plant carbon dioxide (CO2) scrubbing processes, though with major disadvantages such as a 8–35% energy penalty. Here we report that structurally comparable amidoximes are promising CO2 capture agents based on RIMP2 electronic structure calculations. This was experimentally verified by the synthesis and testing of representative amidoximes for capture efficiencies at pressures as high as 180 bar. Acetamidoxime, which has the highest percent amidoxime functionality showed the highest CO2 capacity (2.71 mmol/g) when compared to terephthalamidoxime (two amidoximes per molecule) and tetraquinoamidoxime (four amidoximes per molecule). Polyamidoxime surpassed activated charcoal Norit RB3 for CO2 capture per unit surface area. Adsorption isotherms exhibit Type IV behavior and acetamidoxime found to increase CO2 capture with temperature, a less observed anomaly. Porous amidoximes are proposed as valuable alternatives to MEA.
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CO2 Adsorption Studies on Hydroxy Metal Carbonates M(CO3)x(OH)y (M = Zn, Zn Mg, Mg, Mg Cu, Cu, Ni, and Pb) at High Pressures up to 175 bar
F. Karadas, C. T. Yavuz, S. Zulfiqar, S. Aparicio-Martinez, G. D. Stucky, M. Atilhan*
Langmuir, 27 (17), 10642–10647 (2011). [DOI] [pdf]
Langmuir, 27 (17), 10642–10647 (2011). [DOI] [pdf]
Carbon dioxide (CO2) adsorption capacities of several hydroxy metal carbonates have been studied using the state-of-the-art Rubotherm sorption apparatus to obtain adsorption and desorption isotherms of these compounds up to 175 bar. The carbonate compounds were prepared by simply reacting a carbonate (CO32-) solution with solutions of Zn2+, Zn2+/Mg2+, Mg2+, Cu2+/Mg2+, Cu2+, Pb2+, and Ni2+ metal ions, resulting in hydroxyzincite, hydromagnesite, mcguinnessite, malachite, nullaginite, and hydrocerussite, respectively. Mineral compositions are calculated by using a combination of powder XRD, TGA, FTIR, and ICP-OES analysis. Adsorption capacities of hydroxy nickel carbonate compound observed from Rubotherm magnetic suspension sorption apparatus has shown highest performance among the other components that were investigated in this work (1.72 mmol CO2/g adsorbent at 175 bar and 316 K).
Investigation on novel thermoplastic poly(urethane-thiourea-imide)s with enhanced chemical and heat resistance
A. Kausar, S. Zulfiqar, C. T. Yavuz, M. I. Sarwar*
Polym. Degrad. Stabil., 96 (7), 1333-1341 (2011). [DOI] [pdf]
Polym. Degrad. Stabil., 96 (7), 1333-1341 (2011). [DOI] [pdf]
A new generation of segmented thermoplastic poly(urethane-thiourea-imide)s (PUTIs) was synthesized via reaction of polyethylene glycol and thiourea-based prepolymer with dianhydride as chain extenders. NCO-terminated prepolymer was synthesized from a new diisocyanate, 3-(3-((4-isocyanatophenyl)carbamoyl)thioureido)phenyl-4-isocyanatophenylcarbamate (IPCT), as a hard segment and PEG forming soft segment. The starting materials and polymers were characterized by conventional methods and physical properties such as solubility, solution viscosity, molecular weight, thermal stability and thermal behavior were studied. PUTIs showed partially crystalline structures. Weight average molecular weights of PUTIs (GPC measurements) were in the range of 1,68,694-1,97,035. Moreover, thermogravimetric analysis indicated that poly(urethane-thiourea-imide)s were fairly stable above 500 oC having T10 of 521-543 oC. Investigation of the results authenticated the approach of introducing thiourea (using IPCT) and imide structure in polyurethanes for the improvement of thermal stability. In comparison to typical polyurethanes, these polymers exhibited better heat resistance, chemical resistance as well as processability.
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