Foam Separation

1. FOAM SEPARATION OF TRIBUTYL
PHOSPHATE
BY
M.ARULMOZHI
LECTURER IN CHEMICAL TECHNOLOGY
BHARATHIDASAN INSTITUTE OF TECHNOLOGY
BHARATHIDASAN UNIVERSITY,TRICHY-24

2. Introduction:
 Foam fractionation is a technique useful for the separation and
concentration of complex heat sensitive and chemically unstable materials like
proteins, enzymes, dyes, metal ions etc
 Foam Separation processes have been utilized to separate and concentrate
effectively a variety of constituents from dilute aqueous solutions.
 When a solution containing surface active substances is foamed with an
inert gas, the foam will be richer in these solutes than the residual liquid. This
foam can then be collected and condensed to produce a rich liquid product. The two
characteristic features of foam, useful in separation, are its large gas-liquid
interfacial area and very low liquid holdup

3. Tributyl phosphate(TBP)
 It is a non-flammable, non-explosive, colorless and odorless liquid.
 It has a boiling point of 2890C and solubility in water is 0.42 g/l.
 It is thermally unstable and begins to decompose at temperatures below its
boiling point.
 It is used for solvent extraction and is a very hazardous effluent from nuclear
industry.
 It can not be recovered by distillation because of its high boiling point.

4. EXPERIMENT:
Batch foam column operation is conducted in two sequential steps.
 In the first step, foam is generated up to the desired height by passing gas
bubbles into a pool of liquid.
 In the second step, the foam is permitted to drain. The liquid from the foam
drains into the liquid pool below.

5. The experimental setup consists of
 a glass tube (column),
 filter cloth,
sintered glass tube,
Rubber stopper,
Rota meter
 Compressor etc.,

6. FOAM SEPARATIOPN COLUMN

7. Results and Discussion:
The enrichment ratio and residual ratio are defined respectively as
Enrichment Ratio = Concentration of foam that overflows
Feed Concentration
Residual Ratio= Concentration of bulk liquid in the column
Feed Concentration

8. RESULTS AND DISCUSSION:-
Constants:
Tributyl phosphate concentration = 1.52 * 10-3 mol / l
Air flow rate = 12 LPH
Contact time = 30 min
Height of liquid level = 18 cm
pH = 3.4
variable :
SDS concentration in mol / l
SDS conc.
*10-3
mol /l
Foam conc.
*10-3
mol /l
Residual
conc. *10-3
mol / l
Enrichment
Ratio
Residual
Ratio
1.734
2.600
3.468
4.334
5.020
2.432
2.250
1.976
1.915
1.748
1.246
1.322
1.398
1.459
1.489
1.6
1.48
1.30
1.26
1.15
0.82
0.87
0.92
0.96
0.98

9. SDS conc. vs Enrichment ratio
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
1.734 2.6 3.468 4.334 5.02
SDS conc.(x 10-3 mol/lit)
Enrichment
ratio

10. SDS conc. vs residual ratio
0.7
0.75
0.8
0.85
0.9
0.95
1
1.734 2.6 3.468 4.334 5.02
SDS conc. (x 10-3 mol/l)
Residual
ratio

11. Constants:
SDS concentration = 1.734 * 10-3 mol / lit
Air flow rate = 12 LPH
Contact time = 30 min
Height of liquid level = 18 cm
pH = 3.4
variable :
Tributyl Phosphate concentration in mol / lit
TBP conc.
*10-3
mol /lit
1.52
3.04
4.56
6.08
7.60
Foam
conc.
*10-3
mol /Lit
2.432
4.651
7.159
9.667
11.78
Residual
conc. *10-3
mol / lit
1.246
2.539
3.694
4.934
6.080
Enrichme
nt Ratio
1.6
1.53
1.57
1.59
1.55
Residual
Ratio
0.82
0.83
0.81
0.81
0.80
Recovered TBP concentration increases with the rise in the initial TBP concentration.

12. Initial TBP conc. vs recovered TBP conc.
0
2
4
6
8
10
12
14
1.52 3.04 4.56 6.08 7.6
Initial TBP conc. (x10-3 mol/l)
Recovered
TBP
conc.
(x10-3
mol/l)