Capillary condensation in porous alumina observed by positronium lifetime spectroscopy

<p>Adsorption isotherms are an essential tool in chemical physics of surfaces. However, several approaches based on a different theoretical basis exist and for isotherms including capillary condensation existing approaches can fail. Here, a general isotherm equation is derived and applied to literature data both concerning type IV isotherms of argon and nitrogen in ordered mesoporous silica, and type II isotherms of disordered macroporous silica. The new isotherm covers the full range of partial pressure (10<sup>-6</sup> - 0.7). It relies firstly on the classical thermodynamics of cluster formation, secondly on a relationship defining the free energy during the increase of the cluster size. That equation replaces the Lennard-Jones potentials used in the classical density functional theory. The determination of surface areas is not possible by this isotherm because the cross-sectional area of a cluster is unknown. Based on the full description of type IV isotherms, most known isotherms are accessible by respective simplifications. </p>

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Nanotechnologies � Nanostructured porous alumina as catalyst support for vehicle exhaust emission control � Specification of characteristics and measurement methods

10.3403/30408799 ◽

2021 ◽

Keyword(s):

Porous Alumina ◽

Catalyst Support ◽

Emission Control ◽

Measurement Methods ◽

Exhaust Emission ◽

Vehicle Exhaust

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Catalytic wet air oxidation of dyeing and printing wastewater

Water Science & Technology ◽

10.2166/wst.1997.0145 ◽

1997 ◽

Vol 35 (4) ◽

pp. 311-319 ◽

Cited By ~ 14

Author(s):

L. Lei ◽

X. Hu ◽

H. P. Chu ◽

G. Chen ◽

P. L. Yue

Keyword(s):

High Pressure ◽

Reaction Time ◽

Textile Industry ◽

Porous Alumina ◽

Supported Catalyst ◽

Metal Salts ◽

Treated Wastewater ◽

Catalytic Wet Air Oxidation ◽

Air Oxidation ◽

Wet Air Oxidation

The treatment of dyeing and printing wastewater from the textile industry by oxidation was studied. The reaction was carried out in a two-litre high pressure reactor. In order to promote the oxidation of organic pollutants present in the wastewater, experiments were conducted using various catalysts including metal salts, metal oxides, and porous alumina supported metals. All catalysts tested were able to enhance the conversion of organic compounds in wastewater, shorten the reaction time, and lower the reaction temperature. The alumina supported catalyst has an advantage over other catalysts in that it can be easily separated from the treated wastewater by filtration and recycled. The conditions in preparing the catalyst supported by porous alumina were experimentally optimised.

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Preparation of near net size porous alumina‐calcium aluminate ceramics by gelcasting‐pore‐forming agent processs

Journal of the American Ceramic Society ◽

10.1111/jace.17075 ◽

2020 ◽

Vol 103 (8) ◽

pp. 4602-4610

Author(s):

Bian‐Lei Hao ◽

Ying Lang ◽

Da‐Qian Bian ◽

Chang‐An Wang

Keyword(s):

Calcium Aluminate ◽

Porous Alumina

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Effect of Pore Size Distribution on Capillary Condensation in Nanoporous Media

Langmuir ◽

10.1021/acs.langmuir.0c02775 ◽

2021 ◽

Vol 37 (7) ◽

pp. 2276-2288

Author(s):

Elizabeth Barsotti ◽

Mohammad Piri

Keyword(s):

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Capillary Condensation ◽

Nanoporous Media

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Joining of Porous Alumina with a CaO-Al2 O3 -SiO2 Glass-Ceramic

Journal of the American Ceramic Society ◽

10.1111/jace.12310 ◽

2013 ◽

Vol 96 (6) ◽

pp. 1738-1744 ◽

Cited By ~ 21

Author(s):

Weiwei Zhu ◽

Jichun Chen ◽

Chunhai Jiang ◽

Chuanyong Hao ◽

Jinsong Zhang

Keyword(s):

Glass Ceramic ◽

Porous Alumina ◽

Sio2 Glass

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The Effect of Topology on Phase Behavior under Confinement

Processes ◽

10.3390/pr9071220 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1220

Author(s):

Arnout M. P. Boelens ◽

Hamdi A. Tchelepi

Keyword(s):

Phase Behavior ◽

Density Functional ◽

Capillary Condensation ◽

Good Description ◽

Functional Theory ◽

Minkowski Functionals ◽

First Order ◽

Lennard Jones ◽

And Topology ◽

First Order Transition

This work studies how morphology (i.e., the shape of a structure) and topology (i.e., how different structures are connected) influence wall adsorption and capillary condensation under tight confinement. Numerical simulations based on classical density functional theory (cDFT) are run for a wide variety of geometries using both hard-sphere and Lennard-Jones fluids. These cDFT computations are compared to results obtained using the Minkowski functionals. It is found that the Minkowski functionals can provide a good description of the behavior of Lennard-Jones fluids down to small system sizes. In addition, through decomposition of the free energy, the Minkowski functionals provide a good framework to better understand what are the dominant contributions to the phase behavior of a system. Lastly, while studying the phase envelope shift as a function of the Minkowski functionals it is found that topology has a different effect depending on whether the phase transition under consideration is a continuous or a discrete (first-order) transition.

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