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Warisa Bunmahotama, Wei-Nung Hung, Tsair-Fuh Lin
A new model is developed to predict the competitive adsorption isotherms of atrazine, methyl tertiary butyl ether (MTBE), 2-methylisoborneol (2-MIB) and 2,4,6-trichlorophenol onto activated carbons (ACs) in natural water. Based on the Polanyi-Dubinin (PD) equation, with the limiting pore volume of adsorbent estimated from the pore size distribution data, and the Ideal adsorbed solution theory - equivalent background compound (IAST-EBC) model approximation, the model takes into account both the properties of ACs and the impact of natural organic matters in water...
December 21, 2016: Water Research
Jurn Heinen, Nicholas C Burtch, Krista S Walton, Célia Fonseca Guerra, David Dubbeldam
For the design of adsorptive-separation units, knowledge is required of the multicomponent adsorption behavior. Ideal adsorbed solution theory (IAST) breaks down for olefin adsorption in open-metal site (OMS) materials due to non-ideal donor-acceptor interactions. Using a density-function-theory-based energy decomposition scheme, we develop a physically justifiable classical force field that incorporates the missing orbital interactions using an appropriate functional form. Our first-principles derived force field shows greatly improved quantitative agreement with the inflection points, initial uptake, saturation capacity, and enthalpies of adsorption obtained from our in-house adsorption experiments...
December 12, 2016: Chemistry: a European Journal
Filipe Simões Teodoro, Oscar Fernando Herrera Adarme, Laurent Frédéric Gil, Leandro Vinícius Alves Gurgel
In the second part of this series of studies, the competitive adsorption of three binary systems Cu(2+)-Co(2+), Cu(2+)-Ni(2+) and Co(2+)-Ni(2+) on a carboxylated cellulose derivative (CTA) was evaluated in binary equimolar (1:1) metal-ion aqueous solutions. Bicomponent adsorption studies were developed as a function of contact time and initial metal ion concentration. Bicomponent adsorption kinetic data was modeled by monocomponent kinetic models of pseudo-first- (PFO) and pseudo-second-order (PSO) and a competitive kinetic model of Corsel...
February 1, 2017: Journal of Colloid and Interface Science
Seung-Joon Lee, Tae-Ung Yoon, Ah-Reum Kim, Seo-Yul Kim, Kyung-Ho Cho, Young Kyu Hwang, Jei-Won Yeon, Youn-Sang Bae
The separation of xenon/krypton mixtures is important for both environmental and industrial purposes. The potential of three hydrothermally stable MOFs (MIL-100(Fe), MIL-101(Cr), and UiO-66(Zr)) for use in Xe/Kr separation has been experimentally investigated. From the observed single-component Xe and Kr isotherms, isosteric heat of adsorption (Qst(o)), and IAST-predicted Xe/Kr selectivities, we observed that UiO-66(Zr) has the most potential as an adsorbent among the three candidate MOFs. We performed dynamic breakthrough experiments with an adsorption bed filled with UiO-66(Zr) to evaluate further the potential of UiO-66(Zr) for Xe/Kr separation under mixture flow conditions...
December 15, 2016: Journal of Hazardous Materials
Liping Liu, Jianyong Zhang, Haobin Fang, Liuping Chen, Cheng-Yong Su
Metal-organic frameworks (MOFs) including the UiO-66 series show potential application in the adsorption and conversion of CO2 . Herein, we report the first tetravalent metal-based metal-organic gels constructed from Zr(IV) and 2-aminoterephthalic acid (H2 BDC-NH2 ). The ZrBDC-NH2 gel materials are based on UiO-66-NH2 nanoparticles and were easily prepared under mild conditions (80 °C for 4.5 h). The ZrBDC-NH2 -1:1-0.2 gel material has a high surface area (up to 1040 m(2)  g(-1) ) and showed outstanding performance in CO2 adsorption (by using the dried material) and conversion (by using the wet gel) arising from the combined advantages of the gel and the UiO-66-NH2 MOF...
August 19, 2016: Chemistry, An Asian Journal
Selvan Demir, Nicholas K Brune, Jeffrey F Van Humbeck, Jarad A Mason, Tatiana V Plakhova, Shuao Wang, Guoxin Tian, Stefan G Minasian, Tolek Tyliszczak, Tsuyoshi Yaita, Tohru Kobayashi, Stepan N Kalmykov, Hideaki Shiwaku, David K Shuh, Jeffrey R Long
Porous aromatic frameworks (PAFs) incorporating a high concentration of acid functional groups possess characteristics that are promising for use in separating lanthanide and actinide metal ions, as required in the treatment of radioactive waste. These materials have been shown to be indefinitely stable to concentrated acids and bases, potentially allowing for multiple adsorption/stripping cycles. Additionally, the PAFs combine exceptional features from MOFs and inorganic/activated carbons giving rise to tunable pore surfaces and maximum chemical stability...
April 27, 2016: ACS Central Science
Guido Ori, Carlo Massobrio, Annie Pradel, Michel Ribes, Benoit Coasne
The adsorption and gas separation properties of amorphous porous chalcogenides such as GeS2 are investigated using statistical mechanics molecular simulation. Using a realistic molecular model of such amorphous adsorbents, we show that they can be used efficiently to separate different gases relevant to environmental and energy applications (H2, CO2, CH4, N2). In addition to shedding light on the microscopic adsorption mechanisms, we show that coadsorption in this novel class of porous materials can be described using the ideal adsorbed solution theory (IAST)...
May 21, 2016: Physical Chemistry Chemical Physics: PCCP
Yindong Zhang, Yunlong Zhu, Jun Guo, Shuai Gu, Yuanyuan Wang, Yu Fu, Dongyang Chen, Yijun Lin, Guipeng Yu, Chunyue Pan
A series of novel azo-functionalized copolymerized networks (simply known as NOP-34 series) with tunable permanent microporosity and highly selective carbon dioxide capture are disclosed. The synthesis was accomplished by Zn-induced reductive cross-coupling copolymerization of two nitrobenzene-like building blocks with different 'internal molecular free volumes' (IMFVs), i.e., 2,7,14-trinitrotriptycene and 2,2',7,7'-tetranitro-9,9'-spirobifluorene, with different molar ratios. Increasing the content of spirobifluorene (SBF) segments with a smaller IMFV relative to that of triptycene leads to an unconventional rise-fall pattern in porosity...
April 28, 2016: Physical Chemistry Chemical Physics: PCCP
Nivedita Sikdar, Satyanarayana Bonakala, Ritesh Haldar, Sundaram Balasubramanian, Tapas Kumar Maji
Storage and separation of small (C1-C3) hydrocarbons are of great significance as these are alternative energy resources and also can be used as raw materials for many industrially important materials. Selective capture of greenhouse gas, CO2 from CH4 is important to improve the quality of natural gas. Among the available porous materials, MOFs with permanent porosity are the most suitable to serve these purposes. Herein, a two-fold entangled dynamic framework {[Zn2 (bdc)2 (bpNDI)]⋅4DMF}n with pore surface carved with polar functional groups and aromatic π clouds is exploited for selective capture of CO2 , C2, and C3 hydrocarbons at ambient condition...
April 18, 2016: Chemistry: a European Journal
Ying Wu, Huiyong Chen, Jing Xiao, Defei Liu, Zewei Liu, Yu Qian, Hongxia Xi
The adsorptive separation properties of M-BTC isostructural series (M = Ti, Fe, Cu, Co, Ru, Mo) for methanol-acetone mixtures were investigated by using various computational procedures of grand canonical Monte Carlo simulations (GCMC), density functional theory (DFT), and ideal adsorbed solution theory (IAST), following with comprehensive understanding of adsorbate-metal interactions on the adsorptive separation behaviors. The obtained results showed that the single component adsorptions were driven by adsorbate-framework interactions at low pressures and by framework structures at high pressures, among which the mass effects, electrostatics, and geometric accessibility of the metal sites also played roles...
December 9, 2015: ACS Applied Materials & Interfaces
Ji Woong Yoon, Ji Sun Lee, Sukyung Lee, Kyoung Ho Cho, Young Kyu Hwang, Marco Daturi, Chul-Ho Jun, Rajamani Krishna, Jong-San Chang
A reducible metal-organic framework (MOF), iron(III) trimesate, denoted as MIL-100(Fe), was investigated for the separation and purification of methane/ethane/ethylene/acetylene and an acetylene/CO2 mixtures by using sorption isotherms, breakthrough experiments, ideal adsorbed solution theory (IAST) calculations, and IR spectroscopic analysis. The MIL-100(Fe) showed high adsorption selectivity not only for acetylene and ethylene over methane and ethane, but also for acetylene over CO2 . The separation and purification of acetylene over ethylene was also possible for MIL-100(Fe) activated at 423 K...
December 7, 2015: Chemistry: a European Journal
Zhigang Hu, Samuel Faucher, Yingying Zhuo, Yao Sun, Songnan Wang, Dan Zhao
The strategy to functionalize water-stable metal-organic frameworks (MOFs) in order to improve their CO2 uptake capacities for efficient CO2 separation remains limited and challenging. We herein present an effective approach to functionalize a prominent water-stable MOF, UiO-66(Zr), by a combination of optimization and metalated-ligand exchange. In particular, by systematic optimization, we have successfully obtained UiO-66(Zr) of the highest BET surface area reported so far (1730 m(2)  g(-1) ). Moreover, it shows a hybrid Type I/IV N2 isotherm at 77 K and a mesopore size of 3...
November 23, 2015: Chemistry: a European Journal
Zhuo-Wei Wang, Min Chen, Chun-Sen Liu, Xi Wang, Hui Zhao, Miao Du
A unique Al(III) -based metal-organic framework (467-MOF) with two types of square channels has been designed and synthesized by using a flexible tricarboxylate ligand under solvothermal conditions. 467-MOF exhibits superior thermal and chemical stability and, moreover, shows high CO2 sorption selectivity over H2 , with a selectivity, based on the ideal adsorbed solution theory (IAST) of approximately 45 at 273 or 293 K. Furthermore, its solvent-dependent photoluminescence makes it an applicable sensor in the detection of nitrobenzene explosives through fluorescence quenching...
November 23, 2015: Chemistry: a European Journal
Juan José Gutiérrez-Sevillano, Sofia Calero, Rajamani Krishna
Configurational-bias Monte Carlo (CBMC) simulations are used to establish the potential of CuBTC for separation of water/benzene, methanol/benzene, ethanol/benzene, and acetone/benzene mixtures. For operations under pore saturation conditions, the separations are in favor of molecules that partner benzene; this is due to molecular packing effects that disfavor benzene. CBMC simulations for adsorption of quaternary water/methanol/ethanol/benzene mixtures show that water can be selectively adsorbed at pore saturation, making CuBTC effective in drying applications...
August 21, 2015: Physical Chemistry Chemical Physics: PCCP
Jun Wang, Rajamani Krishna, Jiangfeng Yang, Shuguang Deng
Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model...
August 4, 2015: Environmental Science & Technology
Yae Min Park, Hwan Cheol Park, Ji-Eun Ban, Jong-Il Choi, Hong Euy Lim, Sang Weon Park, Young-Hoon Kim
AIMS: The interatrial septal thickness (IAST) reflects the changes of the atrial wall in patients with atrial fibrillation (AF). Complex fractionated atrial electrograms (CFAEs) were consistently positioned on the interatrial septum, especially in the remodelled left atrium (LA). We sought to characterize the relationship between IAST and LA CFAE area, as well as the acute procedural and clinical outcomes of catheter ablation in persistent AF patients. METHODS AND RESULTS: This study included 71 patients who underwent catheter ablation for drug-refractory persistent AF...
November 2015: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Suha Altarawneh, Timur İslamoğlu, Ali Kemal Sekizkardes, Hani M El-Kaderi
Benzimidazole-linked polymers (BILPs) are emerging candidates for gas storage and separation applications; however, their current synthetic methods offer limited control over textural properties which are vital for their multifaceted use. In this study, we investigate the impact of acid-catalyzed formation rates of the imidazole units on the porosity levels of BILPs and subsequent effects on CO2 and CH4 binding affinities and selective uptake of CO2 over CH4 and N2. Treatment of 3,3'-Diaminobenzidine tetrahydrochloride hydrate with 1,2,4,5-tetrakis(4-formylphenyl)benzene and 1,3,5-(4-formylphenyl)-benzene in anhydrous DMF afforded porous BILP-15 (448 m(2) g(-1)) and BILP-16 (435 m(2) g(-1)), respectively...
April 7, 2015: Environmental Science & Technology
Aalap D Narichania, J William Schleifer, Win-Kuang Shen
Patients with episodic sinus tachycardia and associated orthostatic intolerance present a diagnostic and management dilemma to the clinician. We define this group of disorders to include sinus node reentrant tachycardia (SNRT), inappropriate sinus tachycardia (IAST), and postural orthostatic tachycardia syndrome (POTS). After a brief review of the current understanding of the pathophysiology and epidemiology of this group of disorders, we focus on the diagnosis and management of IAST and POTS. Our approach attempts to recognize the considerable overlap in pathophysiology and clinical presentation between these two heterogeneous conditions...
2014: Cardiology Journal
Kyle K Shimabuku, Hyukjin Cho, Eli B Townsend, Fernando L Rosario-Ortiz, R Scott Summers
This study demonstrates that the ideal adsorbed solution theory-equivalent background compound (IAST-EBC) as a stand-alone model can simulate and predict the powdered activated carbon (PAC) adsorption of organic micropollutants found in drinking water sources in the presence of background dissolved organic matter (DOM) under nonequilibrium conditions. The IAST-EBC represents the DOM competitive effect as an equivalent background compound (EBC). When adsorbing 2-methylisoborneol (MIB) with PAC, the EBC initial concentration was a similar percentage, on average 0...
December 2, 2014: Environmental Science & Technology
Qing Bo Meng, Jens Weber
Suitable solid adsorbents are demanded for carbon capture and storage (CCS) processes. In this work, a novel microporous polymer is developed by hypercrosslinking of organosolv lignin, which is a renewable resource. Reaction with formaldehyde dimethyl acetal (FDA) via Friedel-Crafts reaction gives microporous networks, with moderate capacity of carbon dioxide but excellent selectivity towards CO2 /N2 mixture as predicted on the basis of ideal adsorption-solution theory (IAST). Pyrolysis of pure organosolv lignin results in microporous carbon powders, while pyrolysis of hypercrosslinked organosolv lignin yields shape-persistent materials with increased CO2 capacity while maintaining very good selectivity...
December 2014: ChemSusChem
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