physical adsorption


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physical adsorption

[′fiz·ə·kəl ad′sȯrp·shən]
(physical chemistry)
Reversible adsorption in which the adsorbate is held by weak physical forces.
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The physical adsorption of heavy metal ions in SBAC mainly occurred on the surface.
The adsorption processes are all endothermic, spontaneous, and mainly physical adsorption. The spontaneous degree of the adsorption process followed the order: PDOM > without DOMs > MDOM.
Due to the limited amount of C-S-H gel formation, the infiltration of [Cl.sup.-] lowered the physical adsorption of N[O.sub.2.sup.-], resulting in a relative increase of N[O.sub.2.sup.-] in the pore solution.
The adsorption of [F.sup.-] was mainly due to chemical adsorption with physical adsorption as a complement.
Physical adsorption needs the presence of an electrically charged metal surface and charged species in the bulk solution and the chemisorption process involves charge sharing or charge transfer from the inhibitor molecule to the metal surface.
Fraissard, Physical Adsorption: Experiment, Theory, and Applications, vol.
3 indicates that there is a physical adsorption on the surface with more than on layer, and adsorption energy does not change with the progress of adsorption in the same layer, and there is no interaction among adsorbed molecules [15].
It should be underscored that, although enthalpy was lower than 40 kJ [mol.sup.-1], characterizing a physical adsorption process (Dos Santos et al., 2010), the best adjustment obtained by the pseudo-second order model ([R.sup.2] = 0.997 and 0.999), the rates of the average energy parameter of sorption (E = 11.456 and 11.223) and the low elution percentages (41.77 and 36.83), respectively for metal ions [Cu.sup.2+] and [Zn.sup.2+], indicate the predominance of the chemical nature of the biosorption process.
The physical adsorption and tribochemistry reaction can take place when the steel balls are rubbing, so the contact temperature is raised and the copper oxide surface metal is softened or melted.
The experiments indicate that both chemical adsorption and physical adsorption occur in this system.
Considering Table 1, it can be concluded that X3LYP functional predicts stronger physical adsorption than B3LYP Correlation between the size of the cluster and adsorption energy is according to n: 2 > 3 [greater than or equal to] 4 > 5 > 6 at the X3LYP functional.
At low temperature, gaseous [Hg.sup.0] takes physical adsorption as the primary reaction on the semicoke surface; the gaseous [Hg.sup.0] is primarily absorbed in the micropores, and the surface area and pore structure of semicoke are the principal factors that determine the mercury removal performance.

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