BUBBLE COALESCENCE INHIBITION IN AQUEOUS ELECTROLYTE SOLUTION

1. BUBBLE COALESCENCE INHIBITION IN
AQUEOUS ELECTROLYTE SOLUTION
Presentation By –
Divya Pratap Singh (1500451012)
Kuldeep (1500451016)
Mijul Saxena (1500451020)
Nidhi Tyagi (1500451022)
Supervised by By –
Dr. Ajay Sujan
Department of Chemical Engineering
Raja Balwant Singh Engineering Technical Campus,
Bichpuri, Agra, Uttar Pradesh 283105
Affiliated to Dr. A.P.J. Abdul Kalam Technical University, Lucknow
BATCH 2015–2019

2. 1. Introduction
2. Literature Review
3. Materials and Methods
4. Result and Discussion
5. Conclusion
References
CONTENTS

3.  Dissolved oxygen is required for the respiration of aerobic micro-organisms as well
as fish and other aquatic life in water bodies.
 A fall in dissolved oxygen level is one of the first indications that a water body is
polluted by organic matter.
 Dissolved oxygen levels in natural and wastewaters depend on the physical,
chemical & biochemical activities prevailing in the water body.
INTRODUCTION

4. GAS BUBBLE FORMATION
bubble formation happens in two stages:
First stage: the expansion of the gas
bubbles is assumed to be spherical
Second stage : the buoyancy forces acting
on the gas bubble first pull the bubble away
from the orifice before it completely
detaches from the orifice
Balance of all forces acting on the
bubbles
(FB)Buoyancy + (FM)Gas momentum = (FC)Particle-
bubble collision + (FD)Liquid drag + (FSI)Suspension
Inertia +(FσL)Surface tension + (FIB)Bubble inertia +
(F)Basset
Fan, L.S., Yang, G.Q., Lee, D.J., Tsuchiya, K., Luo, X. “Some Aspects of High-Pressure
Phenomena of Bubbles in Liquid and Liquid-Solid Suspensions,” Chemical Engineering Science,
Vol. 54, (1999), pp. 4681-4709.

5. GAS BUBBLE COALESCENCE
 Coalescence occurs when two gas bubbles first
collide and trap a certain amount of liquid between
them, which once drained may reduce the film
thickness of the bubble to a critical value causing it
to rupture and the gas bubbles to coalescence
(Prince and Blanch (1990) .
 Prince and Blanch (1990) identified three
different forces responsible for bubble collisions:
 turbulence from the random motion of gas
bubbles
 buoyancy from the difference in the rise velocity
of the gas bubbles
 laminar shear, which occurs when the gas bubbles
in the central line liquid circulation interact with
those in a relatively lower circulation zones.
Bubble coalescence in turbulent flow (Chen et al., 2005)

6. INDUSTRIAL APPLICATIONS
o Pulp and paper industry
o Minerals process industry
o Bubble columns
o Bioreactors
o Aerobic wastewater treatment systems
o Aeration process systems
o Chemicals process

7. OBJECTIVE OF CURRENT WORK
To estimate of Bubble coalescence inhibition for different
inorganic electrolyte solutions.
To estimate the transition concentration of aqueous mixture of
single and mixed electrolytes.

8. EXPERIMENTAL SET-UP OF BUBBLE COLUMN
Design
Specifications of experimental setup.

9. PROPERTIES OF ELECTROLYTES

10. OPERATIONAL DETAILS OF EXPERIMENTAL STUDY

11. 1. Experiments were carried out in a borosilicate glass bubble column with an internal diameter of 4
cm and 40 cm height.
2. A contact pairs of air bubbles of approximately the same size were produced at the tip of two
adjacent cannula capillaries (1.2 × 45 mm) by pushing air from a syringe submerged in the aqueous
an inorganic electrolytes solution.
3. Analytical grade of four inorganic electrolytes (Strong electrolyte i.e. CaCl2.2H2O, and Na2SO4
and moderate electrolytes i.e. NaCl, MgSO4.7H2O)(Merck) with purity greater than 99% was used.
4. Electrolytic aqueous solutions were studied over a concentration range of 0 to 0.3 mol/L prepared
with double distilled water.
5. Measurements were made on 80 bubble pairs for each electrolyte concentration.
6. The degree of coalescence was determined by counting the number of coalescing pairs. This was
reported as “percent coalescence” by dividing the number of coalescing pairs by the total number of
pairs contacted.
7. Pairs of air bubbles were formed simultaneously in capillaries of Cannula; the frequency of bubble
formation was 50 ± 4 pairs per minute.

12. RESULTS AND DISCUSSION

13. CONT…

14. COMPARISON OF TRANSITION CONCENTRATION OF INORGANIC
ELECTROLYTES IN AQUEOUS SOLUTION

15. COMPARISON OF TRANSITION CONCENTRATION OF MIXED
INORGANIC ELECTROLYTES IN AQUEOUS SOLUTION

16. CONCLUSION
o The behaviors of bubble coalescence inhibiting or non-inhibiting in the bubble column
are separated by the transition concentrations.
o Transition concentration Ctrans, of inorganic electrolyte for inhibition of bubble
coalescence strongly depends on ion types and their combination.
o All electrolytes were found to inhibit coalescence and experiment results agree with the
combination rule proposed by Craig et l. (1993).
o Anions (Cl- and SO42-) dominating inhibition (below 80% coalescence) at concentration
below 0.175.
o Inhibition strength of CaCl2 is the highest and NaCl is the lowest.
o The behaviour of mixed electrolyte curve was found similar to the behaviour of each
single of them.

17. CONT…
o The strength of electrolyte to inhibit bubble coalescence follows the order: NaCl<
MgSO4< Na2SO4< CaCl2.
o Similarly, the strength of mixed inorganic electrolyte i.e. combination of one strong and
one moderate electrolyte to inhibit bubble coalescence follows the order: (Na2SO4+
NaCl) < (CaCl2+ NaCl).

18. REFERENCES
Christenson HK, Bowen RE, Carlton JA, Denne JRM, Lu Y (2008) Electrolytes that
show a transition to bubble coalescence inhibition at high concentrations. The Journal of
Physical Chemistry C 112(3): 794 – 796.
Craig VS (2011) Do hydration forces play a role in thin film drainage and rupture
observed in electrolyte solutions?. Current opinion in colloid & interface science 16(6):
597 – 600.
Craig VSJ, Ninham BW, Pashley RM (1993) The effect of electrolytes on bubble
coalescence in water. J. Phys. Chem. 97 (39): 10192 –10197.
Deschenes LA, Barrett J, Muller LJ, Fourkas JT, Mohanty U (1998) Inhibition of
bubble coalescence in aqueous solutions. 1. Electrolytes. The Journal of Physical
Chemistry B 102(26): 5115-5119.
Henry CL, Dalton CN, Scruton L, Craig VS (2007) Ion-specific coalescence of bubbles
in mixed electrolyte solutions. The Journal of Physical Chemistry C 111(2): 1015 –1023.

19. Lessard RR, Zieminski SA (1971). Bubble coalescence and gas transfer in aqueous
electrolytic solutions. Industrial & Engineering Chemistry Fundamentals 10(2): 260 –
269.
Marrucci G, Nicodemo L (1967) Coalescence of gas bubbles in aqueous solutions of
inorganic electrolytes. Chem. Eng. Sci. 22:1257–1265.
Marucci G, (1969) Theory of coalescence. Chem. Eng. Sci. 24: 975 – 985.
Prince MJ, Blanch HW (1990) Transition electrolyte concentrations for bubble
coalescence. AIChE J. 36: 1425–1429.
Ribeiro CP, Mewes D (2007) The effect of electrolytes on the critical velocity for bubble
coalescence. Chemical Engineering Journal 126(1): 23 – 33.
Sagert NH, Quinn MJ (1978) The coalescence of gas bubbles in dilute aqueous solutions.
Chem. Eng. Sci. 33: 1087–1095.