What is collids? why purification is needed? what are the process?

1. Prepared By:
Shashi Bhusan Rath
B.Pharm

2.  It is the process of rendering something pure,
i.e., clean of foreign elements.
 The act of process of purifying or the removal
of impurities.

3.  A particular method for performing a task.
 A series of small tasks or steps taken to
accomplish an end.
 Similar to METHOD, PROCESS & ROUTINE.

4.  A colloid is a substance in which
microscopically dispersed insoluble particles
are suspended throughout another substances.
 Ex: Milk is an emulsified colloid of liquid
butterfat globules dispersed within a water-
based solution.

6.  The separation of constituents of the collidal
solution with the help of any separation
process such as centrifugation, dialysis,etc is
known as Purification of Collids.

7.  When a collidal solution is prepared is often
contains certain electrolytes which tend to
destabile it that is why the purification of
collids is done.

8.  The procedure or method for purification of
collids are:-
 Dialysis
 Electro-dialysis
 Ultrafiltration
 Centrifugarion

9.  A method of separating molecules or particles
of different sizes by differential diffusion
through semi-permeable memebrane is
known as Dialysis.
 The process of separating particles of collid
from those of crystalloid by means of diffusion
through a suitable membrane is called Dialysis.
 Thomas Graham (chemist), the founder of
dialysis and father of colloid chemistry.

10.  Its principle based upon the fact that collidal
particles can not pass through membrane while
the ions of electrolyte can pass through it.
 This process is based on the fact that
membranes contain very small pores through
which only dissolved molecules and ions of the
true solution can pass readily.

11.  The impurities slowly diffused out the bag
leaving behind pure collidal solution.
 The fresh or distilled water is changed
frequently to avoid accumulation of the
crystalloids other wise they may start diffusing
back into the bag.

13.  Used in purifying blood through a membrane.
 Can be used for removing HCL from the Ferric
Hydroxide 80%.

14.  To increase the process of purification the
dialysis is carried out by applying electric field.
This process is called electrodialysis.
 Electrodialysis is done in the presence of an
electric potential across the membrane
especially one using an ion selective
membrane.

15.  Used when the substances being removed is an
electrolyte, substance is removed under an
electronic field.
 The electolyte ions pass through the membrane
due to electrostatic pull of oppositely charges
electrodes.

17.  The important application of electrodialysis
process in the artificial kindney machine used
for purification of blood of the patients whose
kidneys have failed to work.
 The artificial kidney machines work on the
priciple of dialysis.
 It is also used for deionization the aqueous
solution.
 Used for Glycerin purification.

19.  It is a filtration in which forces like pressure
leads to a separation through a semi-permeable
membrane.
 Filtration which only allows small molecules
through semi-permeable membrane.
 Here colloids are separated from crystalloids
with the help of ultra filter paper.
 The ultra filter paper was obtained by treating
simple filter paper with gelatin.
 In this ultra filter paper the pores are less or
narrow in size through which only crystalloids
particles can pass.

21.  Impurities are removed from colloids with the
help of a machine of high speed called
centrifugal machine. Colloids settle down
while impurities remains in centrifuge.