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ABSTRACT: Novel silica support has been required for high amine loading and good CO(2) molecule diffusion into its pores to increase the performance of CO(2) adsorbents. Herein, amine groups supported on double-walled silica nanotubes (DWSNTs) have been prepared via the immobilization of various aminosilanes (primary, secondary, tertiary, di-, and tri-aminosilanes) on DWSNT, and found to be a very effective adsorbent for CO(2) capture. Amine groups immobilized DWSNTs captured CO(2) reversibly in a temperature swing process at various adsorption temperatures (25°C, 50°C, 75°C, and 100°C). The amines on modified DWSNTs showed high CO(2) capture capacity in the order of tri-, di-, primary, secondary, and tertiary amines. The CO(2) capture capacity of all aminosilanes immobilized DWSNTs decreased linearly with the increase of the adsorption temperature. We expect that DWSNT would be able to inspire researchers to use it not only as a support for CO(2) capture but also as a promising candidate for various applications.
Journal of hazardous materials 02/2013; 250-251C:53-60. · 4.14 Impact Factor
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ABSTRACT: Electrorheological (ER) effects of alginic acid and alginate salts (Na+ alginate, NH4+ alginate, and Ca2+ alginate) dispersed suspensions were investigated under DC electric fields. A noteworthy result is that the Ca2+ alginate dispersed suspension showed negative electrorheological effects under electric fields while the other suspensions exhibited positive electrorheological effects. It is the first time that the negative ER effect is obtained with the biomacromolecule. Interestingly, at the DC electric fields, the electromigration of particles to two electrodes was observed in the negative ER fluid, while the particles-bridges formed between two electrodes in the case of the positive ER fluid. In conclusion, the specific salt type of biomacromolecules could be suitable ER particles for negative ER suspension. We believe that our study can present a new way for the development of the biocompatible and eco-friendly negative ER fluids.
ACS Applied Materials & Interfaces 01/2013; · 4.53 Impact Factor
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ABSTRACT: Herein, the effect of pH on Cu(II) crystal growth onto the surface of chelating fiber is presented. Poly(acryloamidino ethyleneamine) and poly(acryloamidino diethylenediamine) are synthesized as chelating polymers, and Cu(OH)2 crystal growth with the change of pH in an aqueous solution are observed using field-emission scanning electron microscopy. It is shown that the shapes of grown Cu(II) crystals on the chelating polymers depend on their alkyl amine numbers. The best fits of the isotherm data for Cu2+ adsorption and Cu(OH)2 crystal growth on the chelating polymers are obtained by means of our developed model.
Applied Physics Letters 08/2011; 99(9):094102-094102-3. · 3.84 Impact Factor
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ABSTRACT: Herein, we demonstrate the adsorption process system with the diethylenetriamne coupled polyacrylonitrile fiber for the removal of Cu(II) and Cr(VI) ions in the aqueous solution. The synthesized chelating fiber showed a high adsorption capacity of 11.4 mequiv/g. Interestingly, the crystal growth of copper ions on the chelating fiber was observed during the adsorption process. The chelating fiber packed column showed the high performance of the removal of Cu(II) in the aqueous solution due to the distinct characteristic of the crystal growth of metal ions on the chelating fiber. After Cu(II) adsorption on the chelating fiber, the color of the fiber changed to light blue from yellow. The isotherm parameter n of 1.991 was obtained with Freundlich isotherm model for the adsorption equilibrium study which indicates that Cu(II) adsorption on the chelating fiber is very favorable due to n>1. The pseudo-first-order and pseudo-second-order model equations were used for the kinetic study.
Journal of hazardous materials 08/2011; 194:92-9. · 4.14 Impact Factor
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ABSTRACT: CO(2) emissions, from fossil-fuel-burning power plants, the breathing, etc., influence the global worming on large scale and the man's work efficiency on small scale. The reversible capture of CO(2) is a prominent feature of CO(2) organic-inorganic hybrid adsorbent to sequester CO(2). Herein, (3-aminopropyl) trimethoxysilane (APTMS), [3-(methylamino)propyl] trimethoxysilane (MAPTMS), and [3-(diethylamino) propyl] trimethoxysilane (DEAPTMS) are immobilized on highly ordered mesoporous silicas (SBA-15) to catch CO(2) as primary, secondary, and tertiary aminosilica adsorbents. X-ray photoelectron spectroscopy was used to analyze the immobilized APTMS, MAPTMS, and DEAPTMS on the SBA-15. We report an interesting discovery that the CO(2) adsorption and desorption on the adsorbent depend on the amine type of the aminosilica adsorbent. The adsorbed CO(2) was easily desorbed from the adsorbent with the low energy consumption in the order of tertiary, secondary, and primary amino-adsorbents while the adsorption amount and the bonding-affinity increased in the reverse order. The effectiveness of amino-functionalized (1(o), 2(o), and 3(o) amines) SBA-15s as a CO(2) capturing agent was investigated in terms of adsorption capacity, adsorption-desorption kinetics, and thermodynamics. This work demonstrates apt amine types to catch CO(2) and regenerate the adsorbent, which may open new avenues to designing "CO(2) basket".
Journal of Colloid and Interface Science 04/2011; 361(2):594-602. · 3.07 Impact Factor
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Macromolecular Chemistry and Physics 04/2011; 212(14):1443 - 1450. · 2.36 Impact Factor
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ABSTRACT: Herein, the effect of the degree of deacetylation (DD) on the gelation of the chitosan dispersed suspension as an electrorheological (ER) fluid under an electric field is presented. The fluids were prepared by dispersing the chitin and the chitosan particles having various DDs into silicone oil, and they were evaluated under various electric fields. The alignment of chitosan particles in the fluid was also observed using an optical microscope under the electric field. The formed fibrous structure between electrodes are though to continue to the viscosity increase, because an attempt to move one electrode relative to the order would be hindered by the drag of the dangling fibrils. A noteworthy result is that the region of the frequency for gel state of the ER fluids increased in the order of chitosan DD 99.3, 93.4, 73.2, 83.8, and 87.3% under electric fields while the modulus of the fluids increased in the reverse order. This order was well-matched with the result of dielectric constants and yield stresses of ER fluids. The study of influence of DD on the gelation of the chitosan dispersed suspension under an electric field shows the relevance of the chemical composition of the heteropolysaccharide (chitin-chitosan copolymer) to the rheological and electric properties of ER suspensions.
ACS Applied Materials & Interfaces 03/2011; 3(4):1289-98. · 4.53 Impact Factor
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ABSTRACT: Different-sized particles dispersed electrorheological (ER) fluids were fabricated with poly(acryloamidino diethylenediamine) to observe the influence of the particle size on ER behaviors. The fine particles dispersed ER suspension showed stable shear stress under a DC electric field. On the other hand, the rough particles dispersed suspension showed trembling shear stress which is divided into four regions in a plot of shear stress against shear rate. Our suggested spring-damper model equation treated the wide range of shear rate and specific (trembling) behaviors of shear stress in ER fluids. In this study, we successfully obtained various ER fluids showing different behaviors just by changing the size of particles in the ER fluids. All of the curves of the shear stress plotted against shear rate were fitted well by our spring-damper model.
Journal of Colloid and Interface Science 05/2009; 335(2):183-8. · 3.07 Impact Factor
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ABSTRACT: A polyacrylonitrile (PAN) fiber was adopted for the backbone of a chelate polymer and poly(acrylo-amidino ethylene amine) (PAEA) was prepared through a one-step reaction between the PAN fiber and ethylenediamine (EDA). The maximum removal capacity and degree of substitution were 7.8 meq per gram of dried PAEA and 98%, respectively. The PAEA was tested as an adsorbent in single and two-component metal aqueous solutions under changing pH. The Cu2+ ion accomplished maximum adsorption amount at pH 3 and the order of maximum adsorbed amounts on PAEA is Cu2+ > Ag+ > Zn2+ > Ni2+ > Pb2+ in molar basis. FT-IR spectroscopy was employed to characterize the chemical bonding in metal aqueous solutions and surface morphology was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Copyright © 2004 John Wiley & Sons, Ltd.
Polymers for Advanced Technologies 06/2004; 15(8):459 - 466. · 2.01 Impact Factor
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ABSTRACT: For studying the influences of alkyl chain length, end groups of the side chains, and mixture on enhancing the shear stress of electrorheological (ER) fluids, chitosan carboxylates were synthesized for ER particles and prepared ER fluids by dispersing the particles in silicone oil. After comparing the shear stress of all prepared ER fluids, the conclusion obtained was that ER particles having two functional groups showed higher shear stress than those having one functional group. However, after mixing two ER particles having one functional group respectively, the ER fluid having those particles showed a lower shear stress. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1559–1566, 2004
Journal of Applied Polymer Science 05/2004; 93(4):1559 - 1566. · 1.29 Impact Factor
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ABSTRACT: In this article, we present a new adsorption model of anion particles onto a chelating fiber. Nonideal H+ adsorption on the chelating fiber can be described adequately by the use of the heterogeneity factor β and the parameter Φ indicates the geometric factor of effective concentration in this model. The best fits of amines adsorption data were obtained by means of the developed model using two factors. Poly(acrylo-amidino diethylene diamine) was synthesized as a chelating polymer through the coupling of diethylene triamine with polyacrylonitrile fiber in the presence of AlCl3 · 6H2O addition. Chromate ion and phosphate ion adsorption data on the synthesized poly(acrylo-amidino diethylene diamine) were obtained. Fourier transform infrared studies of these adsorptions were also performed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2430–2440, 2004
Journal of Polymer Science Part B Polymer Physics 05/2004; 42(13):2430 - 2440. · 1.53 Impact Factor
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ABSTRACT: We have been searching a new ion exchange material in the form of a fiber which could get large advantages over the conventional bead type. In this approach, an effective chelating fiber is prepared by the coupling of polyacrylonitrile (PAN) and ethylenediamine. A synthesized ion exchange fiber (poly(acrylo-amidino ethylene amine), PAEA) achieved 7.8 mequiv/g of adsorption capacity in a batch test. The coupling process and capacity were confirmed through FT-IR, acid−base neutralization titration, ICP, IC, and AAS. By means of verifying the bonding peaks (hydrogen and ionic bonding) under several pHs, molecular bonding between PAEA and ions (Cu2+ and CrO42-) was certified. Surface morphologies of chelating fibers and also after metal ion adsorption were examined by AFM. Compared with a batch test, the adsorption ability was low due to the diffusion path of ions in the dynamic test.
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Journal of Polymer Science Part A Polymer Chemistry 03/2004; 42(8):2010 - 2018. · 3.92 Impact Factor
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Journal of Polymer Science Part A Polymer Chemistry 06/2000; 38(15):2815 - 2823. · 3.92 Impact Factor
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ABSTRACT: An electro-rheological (ER) fluid showing trembling shear behavior was fabricated with chitosan particles that had benzene, amine and azo-pendent side groups. This modified-chitosan dispersed suspension showed four regions in a plot of shear stress against shear rate at high electric field. We analyzed this specific behavior with our suggested model. The model was developed with the spring-damper model. Our suggested model equation treated the wide range of shear rate and specific behaviors of shear stress in ER fluids. In this study, we successfully obtained various ER fluids showing different behaviors just by changing the side functional groups of the particles in the ER fluids. All of the curves of the shear stress plotted against shear rate were fitted well by our spring-damper model. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/58575/1/890_ftp.pdf
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ABSTRACT: The main objective of this work is to prepare activated carbon fibers (ACF), analyze a synthesis mechanism of those fibers, and develop a new dye adsorption model. The surface chemical structures of the synthesized viscose rayon phosphates and ACF were analyzed using TOF–SIMS and ATR FT-IR. After steam-activation of carbon fiber at high temperature, the carboxyl group could not be observed due to the high temperature activation. Only the oxygen-contained carbon ring groups appeared. The adsorption mechanism of the developed model in this study, the bottle-neck model, was simple to understand and apply to the industrial adsorption plants. The model could predict theoretical concentration versus time or dye concentration in an ultra accurate manner in the medium and low concentration regions, which could not previously be attempted by other models.
Carbon.
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ABSTRACT: The electrorheological (ER) behavior of a chitosan succinate suspension was investigated by varying the electric fields, volume fractions of particles, and shear rates, respectively. The chitosan succinate suspension showed a typical ER response caused by the polarizability of an amide polar group and shear yield stress due to the formation of multiple chains upon application of an electric field. The shear stress for the suspension exhibited a linear dependence on the volume fraction of particles and an electric field power of 1.88. On the basis of the results, the suspension formulated chitosan succinate as the disperse phase was found to be an anhydrous ER fluid.
Colloids and Surfaces A: Physicochemical and Engineering Aspects.
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ABSTRACT: By this time, when electrorheological (ER) fluids were applied long term, these have been limited because of problems with particle sedimentation. To solve the sedimentation problem, we report on the preparation of hollow polyaniline (PANI) sphere with nano-scale as the disperse phase for estimating electrical and ER properties. A procedure has been developed to coat colloidal polystyrene (PS) core within a PANI shell by chemical oxidation polymerization. The core-shell particles can be turned into spherical hollow PANI shells by dissolution of the PS cores by using organic solvent. The sedimentation of prepared hollow PANI spheres with nano-sized particle in the silicone oil (50 cS) was observed using UV spectrum with time. Also, the suspension showed ER response and good dispersion stability in the silicone oil.
Colloids and Surfaces A Physicochemical and Engineering Aspects 274:37-42. · 2.24 Impact Factor
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ABSTRACT: The analysis on molecular interaction mechanism in the polymer electrolyte film should be preceded since high mobile ions in the film are required to fabricate the high ionic-conducting solid polymer electrolyte. We focused this study on analyzing the molecular interaction mechanism in the novel solid polymer electrolyte comprising cellulose phthalate (CP) and LiClO4. Li+ cation formed not only ionic-bond with carboxyl group but also the coordination with carbonyl and ether groups in CP at the low LiClO4 concentration, while it formed only the ionic-bond at the high concentration. This behavior also influenced the ionic conductivity of the CP/LiClO4 composite that the conductivity values increase rapidly due to the decrease of the coordinations as LiClO4 concentration increases, and then decrease due to the low ionic mobility at higher LiClO4.
Solid State Ionics 181:1178-1182. · 2.65 Impact Factor
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ABSTRACT: This paper focuses on the influence of metal ions on electrorheological and electric properties. The metal particle has not been used as an electrorheological suspension due to the high conductivity and the sedimentation in the suspension although it is expected good electrical properties. In this study, carboxyl group and metal ions were introduced to the surface of the chitosan particle to confirm the influence of the metal ion on the electrorheological property. Although the synthesized chitosan succinate showed good electrorheological property, its metal complex (chitosan succinate–metal complex formed with Al3+, Cu2+, Ni2+, Fe2+, or Zn2+) dispersed suspension showed the low electro-response property and high values of current density and conductivity.
Colloids and Surfaces A Physicochemical and Engineering Aspects 371:76-80. · 2.24 Impact Factor
