scholarly journals Application of cyanated asphaltenes in gas-phase adsorption processes for removal of volatile organic compounds

2019 ◽  
Vol 74 (3) ◽  
pp. 995-1008
Author(s):  
Maksymilian Plata-Gryl ◽  
Malwina Momotko ◽  
Sławomir Makowiec ◽  
Grzegorz Boczkaj
Keyword(s):  
Free Energy ◽  
Adsorption Capacity ◽  
Surface Free Energy ◽  
Adsorption Isotherms ◽  
Retention Volume ◽  
Scale Up ◽  
Breakthrough Curves ◽  
Proton Acceptor ◽  
Acceptor Interaction ◽  
Gas Phase Adsorption

Abstract The paper presents an innovative, chemically modified (methylcyanated) asphaltene-based adsorbent that can be an interesting low-cost alternative for traditional adsorbents. Adsorption properties of adsorbents were examined by inverse gas chromatography technique, adsorption isotherms, and breakthrough curves. A significant increase in retention volume for pyridine, 2-pentanone, nitropropane, toluene, and 1-butanol was observed. Rohrschneider–McReynolds constants revealed an increase in strength of interactions as a result of the modification, especially in strong proton–acceptor interaction (by a factor of 4.6). The surface-free energy of asphaltene adsorbents increased from 136.71 to 169.95 mJ m−2 after modification. It is similar to the surface-free energy of silica or alumina. Moreover, modified adsorbent shows very high adsorption potential for pyridine. Adsorption isotherms revealed that monolayer adsorption capacity for pyridine increased 1.5 times after modification. Breakthrough curves of pyridine indicate that chemical modification increased the adsorption capacity, removal efficiency, and throughput. Scale-up calculations revealed that adsorption column packed with modified asphaltene adsorbent would be almost two times smaller compared to a column packed with unmodified one. Graphic abstract

scholarly journals Roles of adsorption potential and surface free energy on pure CH4 and CO2 adsorption under different temperatures

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 747-755
Author(s):  
Tong-Qiang Xia ◽  
Jing-Yu Meng ◽  
You-Pai Wang ◽  
Jian-Hong Kang ◽  
Hong-Yun Ren
Keyword(s):  
Free Energy ◽  
Adsorption Capacity ◽  
Surface Free Energy ◽  
Gas Adsorption ◽  
Reduction Rate ◽  
Adsorption Potential ◽  
Equilibrium Data ◽  
Different Temperatures ◽  
Static Volumetric Method ◽  
C 50

To fill the knowledge of adsorption characteristics of CH4 and CO2 associated with equilibrium and thermodynamics, adsorption equilibrium tests of pure gas on a coal were conducted under the different temperatures (35 ?C, 50 ?C, and 65?C by the static volumetric method. The equilibrium data were well matched by the SLD-PR model. The influence of some significant factors including temperature, pressure, adsorption potential and surface free energy on gas adsorption capacity were discussed. The results showed that the higher temperature (gas pressure) corresponds to the smaller (larger) adsorption capacity and the larger adsorption potential is, the smaller adsorption capacity is. Taking CH4 as adsorbent, the modified Langmuir equation can well match the SLD-PR model. However, when the adsorption medium is CO2, modified Freundlich equation is better. Using the two modified equations, we study further the relationship among the variation of surface free energy, its reduction rate and gas adsorption capacity. It can be concluded the larger the gas adsorption capacity is, the greater the reduction of surface free energy is, and the smaller the reduction rate of surface free energy is.

scholarly journals Determination of relevance between surface free energy and adsorption capacity of cement particles

2016 ◽  
Vol 21 (3) ◽  
pp. 733-741
Author(s):  
Jihai Yu ◽  
Zhengmao Ye ◽  
Zhenzhen Xia ◽  
Bin Wu ◽  
Pengkun Hou
Keyword(s):  
Free Energy ◽  
Adsorption Capacity ◽  
Surface Free Energy

Smectic A-Smectic B interface : faceting and surface free energy measurement

1989 ◽  
Vol 50 (24) ◽  
pp. 3527-3534 ◽  
Author(s):  
P. Oswald ◽  
F. Melo ◽  
C. Germain
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Energy Measurement ◽  
Smectic A

Examination of the lubricant storing and releasing ability of thermally sprayed surfaces

2011 ◽  
Vol 2 (2) ◽  
pp. 101-105
Author(s):  
L. Fazekas ◽  
Z. S. Tiba ◽  
G. Kalácska
Keyword(s):  
Free Energy ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Essential Role ◽  
Index Number ◽  
Adhesion Ability ◽  
Thermally Sprayed ◽  
Proper Operation

Abstract The lubricant storing and releasing ability of the thermally sprayed surfaces plays an essential role in the proper operation of the components. In the case of porous sprayed surfaces the lubricant storing and releasing ability depends mainly on porosity and the surface energy (adhesion susceptibility). The adhesion ability can also be expressed indirectly with an index number that is by determining the surface free energy.

Molecular orientation of liquid aliphatic hydrocarbons on the surface and at the interface with water

1989 ◽  
Vol 54 (12) ◽  
pp. 3171-3186 ◽  
Author(s):  
Jan Kloubek
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Molecular Orientation ◽  
Phase Changes ◽  
Aliphatic Hydrocarbons ◽  
Water Molecules ◽  
Free Energies ◽  
Dispersion Component ◽  
System Water ◽  
Orientation Of Molecules

The validity of the Fowkes theory for the interaction of dispersion forces at interfaces was inspected for the system water-aliphatic hydrocarbons with 5 to 16 C atoms. The obtained results lead to the conclusion that the hydrocarbon molecules cannot lie in a parallel position or be randomly arranged on the surface but that orientation of molecules increases there the ration of CH3 to CH2 groups with respect to that in the bulk. This ratio is changed at the interface with water so that the surface free energy of the hydrocarbon, γH, rises to a higher value, γ’H, which is effective in the interaction with water molecules. Not only the orientation of molecules depends on the adjoining phase and on the temperature but also the density of hydrocarbons on the surface of the liquid phase changes. It is lower than in the bulk and at the interface with water. Moreover, the volume occupied by the CH3 group increases on the surface more than that of the CH2 group. The dispersion component of the surface free energy of water, γdW = 19.09 mJ/m2, the non-dispersion component, γnW = 53.66 mJ/m2, and the surface free energies of the CH2 and CH3 groups, γ(CH2) = 32.94 mJ/m2 and γ(CH3) = 15.87 mJ/m2, were determined at 20 °C. The dependence of these values on the temperature in the range 15-40 °C was also evaluated.

scholarly journals Effect of calcination temperature on neptunium dioxide microstructure and dissolution

2020 ◽  
Vol 7 (12) ◽  
pp. 3869-3876
Author(s):  
Kathryn M. Peruski ◽  
Brian A. Powell
Keyword(s):  
Grain Size ◽  
Free Energy ◽  
Surface Area ◽  
Calcination Temperature ◽  
Surface Free Energy ◽  
Neptunium Dioxide

Solubility of neptunium dioxide decreases as microstructure grain size increases, likely due to decreasing surface free energy and surface area.

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