lab quiz 1-2 Flashcards
sorption
2 processes. Adsorption and absorption.
absorption
molecules cross the membrane interface to enter the interior of the cell
important physiological process
adsorption
when the molecules (adsorbate) attach to a solid surface (adsorbent/interface).
adsorbate
is a liquid solute in a solution or gas which is being adsorbed
solid surface in adsorption (adsorbent)
called interface
physical adsorption (physisorption)
is a physical process where the adsorbate is held to the surface of the solid by WEAK VAN DER WAALS forces. this adsorbate-adsorbent interaction can easily be broken by changes in temp and pH and adsorbent easily regenerated (process or regeneration is called desorption).
at equilbruim adsorption and desorption are at constant rate
so concentration of the adsorbate is constant
chemical adsorption
is a chemical process where a chemical bond (ionic/covalent) is formed between adsorbent and adsorbate. Stronger adsorbate and adsorbent interactions more challenging to make desorption
Adsorbents are typically classified into three types
adsorbents- used for decoloring and refining food for pharmacological effects.
- hydrophilic and polar oxygen containing compounds, like silica gel
- non-polar carbon containing compounds, such as activated carbon and graphite
- porous polymer matrix with non-polar and polar f-groups
activated charoal
common adsorbent used in pharmacy and medicine. it can adsorb wide range of adsorbates, it is used to treat toxicity due to oral drug indigestion.
the drug gets absorbed by charcoal and this reduces the systemic absorption into GI tract
the amount of absorbate adsorbed is
dependent on the adsorbent qt size, and grade (particle size and quality )
the MOLES of adsorbate adsorbed by A GRAM of adsorbent
is used to express the effectiveness of adsorbent for specific adsorbate.
factors that influence adsorption
temperature
layer
type of adsorption
concentration of adsorbate
quantity of adsorbent
as temperature increases
adsorption will DECREASE (TEMP AND ADSORPTION INVERSALLY PROPORTIONAL)
EXTENT OF adsorption depends on 3 factors
- capacity- SA of adsorbent and receptor sites on adsorbate
2.affinity- properties of adsorbent and adsorbate
- equilibrium conditions (temp and conc of the adsorbate)