This PPT is made under guidance of Prof. V. N. Lad, NIT Surat.

1. Zeta Potential

2. What is Zeta Potential ?
 It is usually denoted using the Greek letter Zeta (ζ),
hence ζ-potential.
Each particle dispersed in a solution is surrounded
by oppositely charged ions called the fixed layer.
Outside the fixed layer, there are varying compositions of
ions of opposite polarities, forming a cloud-like area.
The zeta potential (ζ-potential) is the potential difference
across phase boundaries between solids and liquids.

3. In colloids, Zeta potential is
the electric potential difference
across the ionic layer around a
charged colloid ion.

4. Measurement of Zeta Potential
Marian Smoluchowski’s Formula (1903)

5. Electrostatic repulsion depends on the Zeta potential.
Zeta potential ↑ = Stronger the Repulsion = Stability ↑
For instance, high zeta potential of the fat droplets in milk
prevents them against coalescence. Reduction of it due to
addition of acid would lead to cheese formation from
coalescence droplets.

7. Application of Zeta Potential
Prepare colloidal dispersions for cosmetics, inks, dyes,
foams, and other chemicals
Destroy undesirable colloidal dispersions during water
and sewage treatment
Reduce cost of additives by calculating the minimum
amount needed to achieve a desired effect, such as
amount of flocculant added to water during water
treatment
Many other uses in mineral processing, ceramics
manufacturing, pharmaceutical production, etc.

9. Disclaimer
Created by Vishnu Suthar, NIT Surat
under guidance of
Dr. V. N. Lad, Assistant Professor, NIT Surat