The key difference between flocculation and deflocculation is that flocculation is the formation of flocs by the clumping of fine particles, whereas deflocculation is the dispersion of flocs to form a stable colloid.
Flocculation refers to the formation of clumps from fine particles in a colloid. These clumps are called flocs. We mainly use this term regarding suspensions. Deflocculation, on the other hand, is the opposite of flocculation.
CONTENTS
1. Overview and Key Difference
2. What is Flocculation
3. What is Deflocculation
4. Side by Side Comparison – Flocculation vs Deflocculation in Tabular Form
5. Summary
What is Flocculation?
Flocculation is the formation of clumps by the aggregation of fine particles in a suspension. These clumps are called flocs or flakes. Flocculation may occur spontaneously or due to the addition of a clarifying agent. However, this floc formation is different from precipitation. It is because, in precipitation, dissolved components form a solid while in flocculation, undissolved components form a solid.
Figure 1: Flocculation
After the formation of the floc, it may float to the top of the suspension, settle at the bottom or disperse through the suspension. If the flocs are on the top of the suspension, we call it “creaming”, and if they are at the bottom, we call it “sedimentation”.
What is Deflocculation?
Deflocculation is the dispersion of flocs in a suspension. Deflocculants can make this happen by increasing zeta potential (the potential difference existing between the surface of a solid particle immersed in a conducting liquid (e.g. water) and the bulk of the liquid) and the repulsive forces between particles.
In a deflocculated suspension, collide particles act as individual particles, and there are no flocs or aggregates. Here, the rate of sedimentation is slow because smaller particles rather than large clusters of particles are involved in settling. The supernatant will always have cloudiness in a deflocculated suspension.
What is the Difference Between Flocculation and Deflocculation?
The key difference between flocculation and deflocculation is that flocculation is the formation of flocs by the clumping of fine particles whereas deflocculation is the dispersion of flocs to form a stable colloid. Moreover, flocculation occurs when clarifying agents are added while deflocculation occurs when deflocculants are added.
Furthermore, another significant difference between flocculation and deflocculation is that flocculation decreases the viscosity of a suspension, whereas deflocculation increases the viscosity of a suspension. As a result, the rate of sedimentation in a flocculated suspension is higher than the rate of sedimentation in a deflocculated suspension.
Summary – Flocculation vs Deflocculation
In brief, flocculation and deflocculation are processes that are opposite to each other. The key difference between flocculation and deflocculation is that flocculation is the formation of flocs by the clumping of fine particles, whereas deflocculation is the dispersion of flocs to form a stable colloid.
Reference:
1. “Flocculation.” Wikipedia, Wikimedia Foundation, 23 Apr. 2019, Available here.
Image Courtesy:
1. “Flocculation4” By Brittany2442 – Own work (CC BY-SA 3.0) via Commons Wikimedia