scholarly journals In Situ Recrystallization of Mesoporous Carbon–Silica Composite for the Synthesis of Hierarchically Porous Zeolites

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1640 ◽  
Author(s):  
Jun Du ◽  
Yan Wang ◽  
Yan Wang ◽  
Ruifeng Li
Keyword(s):  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Hierarchical Zeolites ◽  
Hierarchically Porous ◽  
Silica Composite ◽  
Crystallization Procedure ◽  
Cracking Reaction ◽  
Adsorption Desorption

Hierarchically porous ZSM-5 was prepared by utilizing a two-step crystallization procedure with carbon–silica composites as precursors. The hierarchically porous zeolites obtained a regular mesoporous structure with aluminum incorporated into the carbon–silica composite frameworks. The carbon–silica composite zeolites were characterized by XRD, TEM, SEM, and nitrogen adsorption/desorption. As-prepared hierarchical zeolites were used in the 1,3,5-triisopropylbenzene (TIPB) cracking reaction and exhibited significantly high TIPB conversion, while the accessibility factors were also determined.

MESOPOROUS CARBON ELECTRODE: SYNTHESIS, CHARACTERIZATION AND ELECTROCHEMICAL PROPERTIES

2010 ◽  
Vol 03 (03) ◽  
pp. 161-164 ◽  
Author(s):  
XI LONG ◽  
CHUNXIA ZHAO ◽  
WEN CHEN
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Constant Current ◽  
Surface Areas ◽  
Constant Current Charge ◽  
Adsorption Desorption ◽  
Charge Discharge

The present paper studies a kind of mesoporous carbon (MC) with high electrochemical performance, which was prepared by vapor infiltration method. The microstructure and electrochemical properties of the mesoporous carbon were investigated by transmission electron microscopy (TEM), nitrogen adsorption–desorption isotherms, cyclic voltammetry (CV), constant current charge–discharge cycling (CD), and the long-term stability test. The results indicated that the mesoporous carbon has an ordered mesoporous structure, with pore size of about 3.87 nm and surface areas of 1087 m2 ⋅ g-1. The cyclic voltammetry curve reveals typical electrical double-layer capacitor property. After 200 cycles, the CV curves can almost be overlapped, which indicates excellent cycling stability. From the charge/discharge cycling, the specific capacitance of MC is 117 F ⋅ cm-1 in 1.0 M KNO3 electrolyte media at a scan rate of 1.0 mV ⋅ s-1, which decays with increasing current density. The charge–discharge efficiency also decays with it.

scholarly journals SYNTHESIS AND ELECTROCHEMICAL PROPERTIES OF MESOPOROUS CARBON SUPPORTED WELL–DISPERSED COBALT OXIDES NANOPARTICLES

2018 ◽  
Vol 55 (1B) ◽  
pp. 230
Author(s):  
Nguyen Van Tu
Keyword(s):  
Electron Microscopy ◽  
Cobalt Oxide ◽  
Mesoporous Carbon ◽  
Good Control ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Oxide Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Transmission Electron ◽  
Adsorption Desorption

In this article, well–dispersed cobalt oxide nanoparticles supported on mesoporous carbon (CMK–3) have been successfully synthesized. The composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, X–ray diffraction and nitrogen adsorption–desorption analysis. The results have confirmed that, at a cobalt loading of 15 wt%, the composites have not only retained mesoporous structure of the support but also shown a good control of dispersed cobalt oxide nanoparticles with size of ~4 nm. The electrochemical property tests for the synthesized samples have shown significant improvement compared to the blank carbon (CMK–3) without cobalt oxide incorporation.

scholarly journals ADSORPTION PROPERTIES OF TITANIA-SILICA MEMBRANES OBTAINED ON CERAMIC SUBSTRАTE

2018 ◽  
Vol 54 (3) ◽  
pp. 274-280
Author(s):  
T. F. Kouznetsova ◽  
A. I. Ivanets ◽  
J. D. Sauka
Keyword(s):  
Surface Area ◽  
Quartz Substrate ◽  
Cetylpyridinium Chloride ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Adsorption Properties ◽  
Molar Ratio ◽  
Silica Membranes ◽  
Metal Silicate ◽  
Adsorption Desorption

Titania-silica membranes on a porous quartz substrate are prepared by its direct contact with metal silicate sol at various Ti/Si ratios in the conditions of coagel sedimentation and presence of cetylpyridinium chloride. The study of textural and adsorption properties of membranes is conducted by low-temperature nitrogen adsorption-desorption, including methods of t-plots and DFT theory. It was shown that obtained membranes have mesoporous structure with the specific surface area and pore hydraulic diameter varied in intervals of 64–217 m2 /g and 4–11 nm, respectively. Developed values of surface area remain up to molar ratio of Ti/Si = 50/50.

Synergetic effects of Cu-Zn bimetallic ions exchanged in NaX on acid sites of M(x)X zeolites (M = Cu2+ and/or Zn2+, x = level of exchange). An in situ FTIR study using pyridine adsorption/desorption

2019 ◽  
Vol 107 (3) ◽  
pp. 304
Author(s):  
Habib Hammoudi ◽  
Souhila Bendenia ◽  
Isabelle Batonneau-Gener ◽  
Jean-dominique Comparot ◽  
Kheira Marouf-Khelifa ◽  
...  
Keyword(s):  
Synergetic Effect ◽  
Nitrogen Adsorption ◽  
Acid Sites ◽  
Lewis Acidity ◽  
Pyridine Adsorption ◽  
In Situ Ftir ◽  
Desorption Temperature ◽  
X Zeolites ◽  
Adsorption Desorption

X zeolites were prepared by ion-exchange with Cu2+ and/or Zn2+ cations, at different concentrations of the exchange solution, and characterized by thermal analysis and nitrogen adsorption. The acidity of the samples was investigated by pyridine adsorption–desorption followed by in situ Fourier transform infrared (FTIR) spectroscopy. Desorption was carried out at 150, 250 and 350 °C. The objective is to estimate the nature and concentration of acid sites. A comparison between the binary (Cu(x)X, Zn(x)X) and ternary (CuZn(x)X) exchanges was also established (x = level of exchange) through the Cu(43)X, Zn(48)X and CuZn(50)X samples. Lewis acidity decreases overall with desorption temperature and the level of exchange. As the latter increases, there is a conversion of some Lewis sites into those of Brønsted during thermal treatment. In return, the concentration of Brønsted sites increases with the degree of exchange. The Brønsted acidity of CuZn(50)X at 350 °C is more important than the sum of those of Cu(43)X and Zn(48)X with respectively values of 73, 32 and 15 μmol g−1. Besides, the concentration of Brønsted sites for CuZn(50)X increases with desorption temperature. These features indicate the presence of a synergetic effect amplifying the strength of these sites when Cu2+ and Zn2+ cations compete for the occupancy of sites distributed in zeolite cavities.

scholarly journals Electrochemical behavior of H3PW12O40/ acid-activated bentonite powders

2012 ◽  
Vol 18 (2) ◽  
pp. 329-338 ◽  
Author(s):  
Zorica Mojovic ◽  
Ljiljana Rozic ◽  
Tatjana Novakovic ◽  
Zorica Vukovic ◽  
Srdjan Petrovic ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Limit Of Detection ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Nitrite Oxidation ◽  
Face To Face ◽  
Force Microscopy ◽  
Atomic Force ◽  
Activated Bentonite ◽  
Adsorption Desorption

Electrochemical behavior of 12-tungstophosphoric acid (HPW)/acid-activated bentonite (AAB) powders with various loadings of HPW was investigated. The physicochemical properties of the prepared powders were examined by X-ray powder diffraction, nitrogen adsorption-desorption isotherms, atomic force microscopy and cyclic voltammetry measurements. The results indicated that the prepared powders are composed mainly of oriented domains of large rock blocks, probably resulting from a preferable deposition of bentonite particles having a face-to-face interaction. The particles had a mainly disordered mesoporous structure with a pore volume that varied according to the pore size in the range of 2-50 nm. In addition, the particles had crystallite size between 4.9 and 9.0 nm. The electrocatalytic activities of prepared HPW/Aelectrodes were studied in the oxidation of NO2-ions and the results revealed that the electrodes possessed relatively higher nitrite oxidation currents than Aelectrode. The best electroactivity was observed for HPW3/Aelectrode (AAB+20 wt. % HPW) and the limit of detection (3?) was determined as 8 ?M.

Synthesis of Ni(II)-imprinted Mesoporous Silica Adsorbents by Surface Imprinting Technology for Removal of Ni(II) from Aqueous Solution

2014 ◽  
Vol 997 ◽  
pp. 146-149
Author(s):  
Xiang Guo Meng ◽  
Wen Lu Guo ◽  
Min Luo ◽  
Ping Sun
Keyword(s):  
Aqueous Solution ◽  
Mesoporous Silica ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Surface Imprinting ◽  
Surface Imprinting Technique ◽  
Silica Adsorbents ◽  
Ft Ir ◽  
Surface Imprinting Technology ◽  
Adsorption Desorption

Ni(II)-imprinted polymer has been prepared by surface imprinting technique based on support matrix of mesoporous silica SBA-15. The obtained adsorbent was characterized by FT-IR, SEM, and nitrogen adsorption-desorption. The compound retained mesoporous structure and the polymer coated inside channels and outside surface hole wall. The adsorption behavior was carried out with Ni(II)-IIP in batch experiments. The results suggested that Ni(II)-IIP could be used as an excellent adsorbent for efficient removal of Ni(II) from aqueous solution.

Preparation and Characterization of Cobalt Modified Rectorite

2013 ◽  
Vol 773 ◽  
pp. 263-266 ◽  
Author(s):  
Xiao Rong Zhao ◽  
Li Hua Zhu ◽  
He Qing Tang
Keyword(s):  
Nitrogen Adsorption ◽  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
Step Method ◽  
Bet Specific Surface Area ◽  
Pore Properties ◽  
Adsorption Desorption ◽  
Resultant Material

Cobalt modified rectorite (Co@R) was prepared from sodium saturated rectorite (Na-R) with a two-step method of microwave-assisted ion-exchange and in-situ hydrolysis. The morphology, composite structure and pore properties of Co@R were observed with scanning electron microscopy (SEM), small angle X-ray Diffraction (XRD) and nitrogen adsorption-desorption isotherm. The adsorption ability and catalytic behavior of Co@R were studied with methyl blue (MB) as probe contaminant. The interstratified layered Na-R was stripped fully and the resultant material remained the layered structure with a slit-shaped pore between the layers of lamellar particles. The interlayer spacingd001of rectorite was increased successfully from 2.23 nm up to 2.72 nm. The Co@R has a BJH pore volume of 0.091 cm3g-1resulting from the macropores and BET specific surface area of 28.5 m2g-1. A set of test has shown that Co@R possesses the potential to become a good adsorbent and catalyst for activating peroxymonosulfate (PMS), removing organic pollutants efficiently.

scholarly journals Study of Adsorption Capacity of Dibenzotiofen Molecules on Mesoporous Carbon with Pore Geometry Model

2017 ◽  
Vol 2 (2) ◽  
pp. 110
Author(s):  
Maria Ulfa ◽  
Farhah Nayla Fawzia
Keyword(s):  
Adsorption Capacity ◽  
Mesoporous Carbon ◽  
Nitrogen Adsorption ◽  
Pore Geometry ◽  
Adsorption Models ◽  
Geometry Model ◽  
Molecular Arrangement ◽  
Model Molecule ◽  
Adsorption Desorption ◽  
Range Of Values

<p>Adsorption models in a simple and accurate way to describe the geometry of the pores have been studied and validated experimentally to predict the adsorption capacity dibenzotiofen molecules on mesoporous carbon. The model is designed according to the size of the pore channels of mesoporous carbon and molecular arrangement dibenzotiofen that goes into the pores. To test the accuracy of the model is done by comparation with results of analysis of nitrogen adsorption-desorption to calculate the volume filled. The results showed that the results of the experimental adsorption data are within the range of values of the pore volume of mesoporous carbon. These results indicate that the pore geometry model molecule can accurately predict the adsorption capacity of a molecule in a mesoporous material.</p><p class="AbstracttitleDERJournal"> </p>

DEVELOPMENT OF MAGNETICALLY RESPONSIVE Fe3O4@C CORE/SHELL MICROSPHERES AS POTENTIAL VECTORS FOR DRUG-DELIVERY APPLICATIONS

NANO ◽  
2013 ◽  
Vol 08 (04) ◽  
pp. 1350039 ◽  
Author(s):  
WENJING YUAN ◽  
LING ZHU ◽  
PING CHEN ◽  
ANJIAN XIE ◽  
HUI ZHANG ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Electron Microscope ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Bet Surface Area ◽  
Core Shell ◽  
Bovine Hemoglobin ◽  
Hydrothermal Route ◽  
Model Protein ◽  
Adsorption Desorption

The Fe3O4@C core/shell microspheres were fabricated via a two-step process. Fe3O4 microspheres were firstly prepared, and Fe3O4@C core/shell microspheres were subsequently fabricated using glucose as a carbon source by a hydrothermal route, in which the thickness of the carbon coating was about 20 nm. The resulting products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR). The Nitrogen adsorption–desorption isotherms reveal their mesoporous structure and larger BET surface area (62.3 m2g-1). The Fe3O4@C core/shell microspheres possess ferromagnetism and high saturation magnetization (39.2 emu ⋅ g-1). Bovine hemoglobin (BHb) was used as a model protein to test the adsorption and desorption properties of the Fe3O4@C core/shell microspheres. The capacity for BHb adsorption was more than 71.3 mg/g. According to the values obtained in the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay the Fe3O4@C core/shell microspheres show a low toxicity. Therefore, the prepared Fe3O4@C core/shell microspheres are of great significance for guided site-specific drug delivery.

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