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Gaseous and liquid particles adsorb on solid surfaces. Can solid particles suspended in a fluid medium also adsorb on these surfaces in the same manner?

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    $\begingroup$ Suspended particles don't adsorb, molecules do. $\endgroup$
    – Mithoron
    Jul 25, 2021 at 20:04
  • $\begingroup$ @Mithoron, Bacterial cells are said to adsorb on glass surfaces. Are bacterial cells molecules? $\endgroup$
    – AChem
    Jul 25, 2021 at 20:21
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    $\begingroup$ @M.Farooq Maybe biologist would consider binding of bacteria to surface an adsorption, but for a chemist there's a whole phase inside a bacteria. How big particles are supposed to be to not be "adsorbate"? When calling something adsorption is gonna have a different meaning? $\endgroup$
    – Mithoron
    Jul 25, 2021 at 21:57
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    $\begingroup$ Terminology is a grey area and modern science is all interdisciplinary. Adsorption of very small "particles" is a well known phenomenon as illustrated below and in the field of biochemistry/biology. $\endgroup$
    – AChem
    Jul 26, 2021 at 17:43

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Yes, even very small particles can "stick" permanently to solid surfaces in solution just like gases or liquids. Just note that the particles have to be nanometer sized. One classical discovery, which made million dollar business in the field of chromatography is that of so-called agglomerated ion-exchange phases (Dionex).

Basically you have negatively charged particles, such as a sulfonated resins. The sulfonate group on the surface has a negative charge. Now expose this resin to a nanometer sized suspension of polymeric particles bearing quarternary amine groups (so called latex). The positive charge on this colloid helps to stick to the negatively charged resin. In the scanning electron microscope, the solids bead look this this. I cannot find the original SEM at this moment (This work was done in 80s)

This "adsorption" is almost permanent. Nothing can get rid of this latex coating on the particles.

enter image description here

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  • $\begingroup$ So we can say that any adsorbent doesn’t require a recognition of its state because of its particulate size, right? $\endgroup$ Jul 25, 2021 at 18:41
  • $\begingroup$ Welcome, it depends on particles dimensions. You cannot have a 5 micron particle adsorp on a 10 micron particle. $\endgroup$
    – AChem
    Jul 25, 2021 at 19:01

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