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A study on metal organic framework (MOF-177) synthesis, characterization and hydrogen adsorption -desorption cycles  [PDF]
V.Viditha, M.Venkateswer Rao, K.Srilatha11, V.Himabindu, Anjaneyulu Yerramilli
International Journal of Energy and Environment , 2013,
Abstract: Hydrogen has long been considered to be an ideal alternative to fossil-fuel systems and much work has now been done on its storage. There are four main methods of hydrogen storage: as a liquid; as compressed hydrogen; in the form of metal hydrides; and by physisorption. Among all the materials metal organic frameworks (MOFs) are considered to have desirable properties like high porosity, pore volume and high thermal stability. MOF-177 is considered to be an ideal storage material. In this paper we study about its synthesis and hydrogen storage capacities of MOF-177 at different pressures ranging from 25, 50, 75 and 100 bar respectively. The obtained samples are characterized by XRD, BET and SEM. The recorded results show that the obtained hydrogen capacity is 1.1, 2.20, 2.4 and 2.80 wt%. The desorption capacity is 0.9, 2.1, 2.37 and 2.7 wt% at certain temperatures like 373 K.
Synthesis and Characterization of MOF-199: A Potential Sensing Material  [PDF]
L. Brinda,K.S. Rajan,John Bosco Balaguru Rayappan
Journal of Applied Sciences , 2012,
Abstract: Metal Organic Frameworks (MOFs) are frameworks of 1-3D formed by the interaction between organic molecules and metal ions/clusters. The high specific surface area (~1000-5000 m2 g-1) and large pore volume (~0.7-2.5 cc g-1) of these molecules render them as ideal candidates for catalysis, gas absorption, separation of gases and sensing applications. The pore size and surface area can be tailored by modifying the synthetic conditions. In this paper, we report the synthesis and characterization of MOF-199 for potential application in enzyme-based sensing. MOF-199 was synthesized under room temperature using benzenetricarboxylic acid and a 1:1:1 mixture of DMF/ethanol/copper (II) acetate. Further, triethylamine (0.5 mL) was added to the reaction mixture and the resultant mixture was stirred for 23 h followed by drying to obtain a bluish crystalline material of MOF-199. The crystalline material was characterized using various analytical and microscopic techniques.
Metal Organic Framework (MOF-5) For Sensing of Volatile Organic Compounds  [PDF]
N. Iswarya,M. Ganesh Kumar,K.S. Rajan,John Bosco Balaguru Rayappan
Journal of Applied Sciences , 2012,
Abstract: Metal Organic Framework-5 (MOF-5) can be used for sensing of Volatile Organic Compounds (VOCs). VOCs are emitted from biological sources, paints, coatings, etc. and they pollute the environment thus posing serious health and environmental hazards. MOF-5 is a three dimensional crystalline coordination compound made up of Zn4O inorganic group as the vertex and benzene decarboxylate organic group as the spacer in the unit cell of the crystal. This study reported the synthesis and characterization of MOF-5 and its capability towards sensing of VOCs like ethanol, formaldehyde and acetone. Transmission Electron Micrograph reveals that the synthesized sample is highly crystalline and porous. BET surface area obtained was found to be 230 m2 g-1. MOF-5 was made into pellets of thickness around 3 mm for sensing purposes. The material was found to be sensitive towards ethanol even at concentrations as low as 5 ppm, towards formaldehyde at higher concentrations and towards acetone at concentrations as low as 10 ppm. The order of increase in sensitivity is ethanol>formaldehyde>acetone.
Synthesis and characterization of calcium phosphate and its relation to Cr(VI) adsorption properties
GRANADOS-CORREA, Francisco;BONIFACIO-MARTíNEZ, Juan;SERRANO-GóMEZ, Juan;
Revista internacional de contaminación ambiental , 2010,
Abstract: calcium phosphate with hydroxyapatite structure was synthesized and its ability to adsorb cr(vi) from aqueous solution is presented. xrd, bet, ir, tga, sem and eds techniques were used to characterize the obtained material. apure phase was obtained through a simple synthesis process. the specific surface area of the synthesized powder was found to be 64.5 m2 g-1. the x-ray diffraction pattern shows that the calcium phosphate formed was nanocrystalline with an average grain size of approximately 75 nm. a fast adsorption was observed and in less than 24 h it was found that 2.41 x 10-4 meq g-1 of cr(vi) ions were adsorbed on calcium phosphate. desorption experiments showed that cr(vi) adsorption decreased to 2.23 x 10-4 meq g-1 of calcium phosphate. this behavior is a consequence of partial dehydration of the synthesized material. calcium phosphate can be effectively used for removing cr(vi) from aqueous solutions in treatment processes of metal wastes.
SYNTHESIS AND CHARACTERIZATION OF CALCIUM PHOSPHATE AND ITS RELATION TO CR(VI) ADSORPTION PROPERTIES
RAJEEV KR. JHA
Review of Research , 2012,
Abstract: Calcium phosphate with hydroxyapatite structure was synthesized and its ability to adsorb Cr(VI) from aqueous solution is presented. XRD, BET, IR, TGA, SEM and EDS techniques were used to characterize the obtained material. Apure phase was obtained through a simple synthesis process. The specific surface area of the synthesized 2 –1powder was found to be 64.5 m g . The X–ray diffraction pattern shows that the calcium phosphate formed was nanocrystalline with an average grain size of approximately 75 –4nm. Afast adsorption was observed and in less than 24 h it was found that 2.41 x 10 meq –1g of Cr(VI) ions were adsorbed on calcium phosphate. Desorption experiments showed –4 –1that Cr(VI) adsorption decreased to 2.23 x 10 meq g of calcium phosphate. This behavior is a consequence of partial dehydration of the synthesized material. Calcium phosphate can be effectively used for removing Cr(VI) from aqueous solutions in treatment processes of metal wastes
Synthesis, characterization, and adsorption performance of Pb(II)-imprinted polymer in nano-TiO2 matrix
Synthesis, characterization, and adsorption performance of Pb(Ⅱ)-imprinted polymer in nano-TiO2 matrix

LI Chunxiang,GAO Jie,PAN Jianming,ZHANG Zulei,YAN Yongsheng,
LI Chunxiang
,GAO Jie,PAN Jianming,ZHANG Zulei,YAN Yongsheng

环境科学学报(英文版) , 2009,
Abstract: Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(II)-imprinted polymer for selective separation and enrichment of trace Pb(II) from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray di ractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb(II) from aqueous solutions on Pb(II)-imprinted polymer. The equilibrium was achieved in approximately 4.0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb(II) on Pb(II)-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb(II) from the Pb(II)-imprinted polymer were also studied in batch experiments. The prepared Pb(II)-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb(II) from water samples. The adsorption and desorption mechanisms were proposed.
NMR study of small molecule adsorption in MOF-74-Mg  [PDF]
M. G. Lopez,Pieremanuele Canepa,T. Thonhauser
Physics , 2013, DOI: 10.1063/1.4800952
Abstract: We calculate the carbon nuclear magnetic resonance (NMR) shielding for CO_2 and the hydrogen shieldings for both H_2 and H_2O inside the metal organic framework MOF-74-Mg. Our ab initio calculations are at the density functional theory level using the van der Waals including density functional vdW-DF. The shieldings are obtained while placing the small molecules throughout the structure, including the calculated adsorption site for various loading scenarios. We then explore relationships between loading, rotational and positional characteristics, and the NMR shieldings for each adsorbate. Our NMR calculations show a change in the shielding depending on adsorbate, position, and loading in a range that is experimentally observable. We further provide a simple model for the energy and the NMR shieldings throughout the cavity of the MOF. By providing this mapping of shielding to position and loading for these adsorbates, we argue that NMR probes could be used to provide additional information about the position at which these small molecules bind within the MOF, as well as the loading of the adsorbed molecule.
High-throughput screening of small-molecule adsorption in MOF  [PDF]
Pieremanuele Canepa,Calvin A. Arter,Eliot M. Conwill,Daniel H. Johnson,Brian A. Shoemaker,Karim Z. Soliman,T. Thonhauser
Physics , 2013, DOI: 10.1039/C3TA12395B
Abstract: Using high-throughput screening coupled with state-of-the-art van der Waals density functional theory, we investigate the adsorption properties of four important molecules, H_2, CO_2, CH_4, and H_2O in MOF-74-M with M = Be, Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Ru, Rh, Pd, La, W, Os, Ir, and Pt. We show that high-throughput techniques can aid in speeding up the development and refinement of effective materials for hydrogen storage, carbon capture, and gas separation. The exploration of the configurational adsorption space allows us to extract crucial information concerning, for example, the competition of water with CO_2 for the adsorption "pockets." We find that only a few noble metals---Rh, Pd, Os, Ir, and Pt---favor the adsorption of CO_2 and hence are potential candidates for effective carbon-capture materials. Our findings further reveal significant differences in the binding characteristics of H_2, CO_2, CH_4, and H_2O within the MOF structure, indicating that molecular blends can be successfully separated by these nano-porous materials.
Synthesis, characterization and determination of the metal ions adsorption capacity of cellulose modified with p-aminobenzoic groups
Castro, Gustavo Rocha de;Alcantara, Ilton Luiz de;Roldan, Paulo dos Santos;Bozano, Dorotéia de Fátima;Padilha, Pedro de Magalh?es;Florentino, Ariovaldo de Oliveira;Rocha, Julio Cesar;
Materials Research , 2004, DOI: 10.1590/S1516-14392004000200018
Abstract: this paper describes the synthesis and characterization of p-aminobenzoic modified cellulose (cell-pab), as well as the separation and preconcentration of cd(ii), cu(ii), ni(ii), pb(ii) and zn(ii) ions from an aqueous medium using a cell-pab bath and the column technique. the quantity of p-aminobenzoic groups attached to the cellulose surface, i.e., 1.81±0.04 mmol/g, was determined by elemental analysis. the ft-ir spectra of cell-pab revealed characteristic bands of p-aminobenzoic groups, indicating the desired functionalization of the cellulose surface. the adsorptive capacities for the metals (ns) cd, cu, ni, pb and zn (ns) were, respectively, 1.72 ± 0.02, 1.96 ± 0.02, 1.88 ± 0.04, 2.01 ± 0.03 and 1.93 ± 0.03 mmol/g. metal separations performed in flow experiments using a column packed with 1 g of cell-pab and 5 ml of 1.5 mol/l hcl solution as eluent achieved an almost 100% metal ions recovery rate.
Synthesis, characterization and determination of the metal ions adsorption capacity of cellulose modified with p-aminobenzoic groups
Castro Gustavo Rocha de,Alcantara Ilton Luiz de,Roldan Paulo dos Santos,Bozano Dorotéia de Fátima
Materials Research , 2004,
Abstract: This paper describes the synthesis and characterization of p-aminobenzoic modified cellulose (Cell-PAB), as well as the separation and preconcentration of Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) ions from an aqueous medium using a Cell-PAB bath and the column technique. The quantity of p-aminobenzoic groups attached to the cellulose surface, i.e., 1.81±0.04 mmol/g, was determined by elemental analysis. The FT-IR spectra of Cell-PAB revealed characteristic bands of p-aminobenzoic groups, indicating the desired functionalization of the cellulose surface. The adsorptive capacities for the metals (Ns) Cd, Cu, Ni, Pb and Zn (Ns) were, respectively, 1.72 ± 0.02, 1.96 ± 0.02, 1.88 ± 0.04, 2.01 ± 0.03 and 1.93 ± 0.03 mmol/g. Metal separations performed in flow experiments using a column packed with 1 g of Cell-PAB and 5 mL of 1.5 mol/L HCl solution as eluent achieved an almost 100% metal ions recovery rate.
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