The American Journal of Applied Sciences
6
https://www.theamericanjournals.com/index.php/tajas
TYPE
Original Research
PAGE NO.
6-12
10.37547/tajas/Volume07Issue03-02
OPEN ACCESS
SUBMITED
03 January 2025
ACCEPTED
05 February 2025
PUBLISHED
07 March 2025
VOLUME
Vol.07 Issue03 2025
CITATION
Salikhanova Dilnoza Saidakbarovna, Ismoilova Mukhtasar Аbdumutolib
qizi, Sagdullayeva Dilafruz Saidakbarovna, Choriyeva Iklima Yuldosh qizi,
Savriyeva Dilafruz Doutovna, & Muratov Mirtokhir Mirkhalil ugli. (2025).
Investigation of the effects of ultrasound processing on the characteristics
of lubricating emulsions. The American Journal of Applied Sciences, 7(03),
6
–
https://doi.org/10.37547/tajas/Volume07Issue03-02
COPYRIGHT
© 2025 Original content from this work may be used under the terms
of the creative commons attributes 4.0 License.
Investigation of the
effects of ultrasound
processing on the
characteristics of
lubricating emulsions
Salikhanova Dilnoza Saidakbarovna
Doctor of Chemical Sciences, Professor, Institute of General and
Inorganic Chemistry of the Academy of Sciences of Uzbekistan,
Tashkent, Uzbekistan
Ismoilova Mukhtasar Аbdumutolib qizi
PhD, Institute of General and Inorganic Chemistry of Academy of
Sciences of the Republic of Uzbekistan, Tashkent, Uzbekistan
Sagdullayeva Dilafruz Saidakbarovna
Doctor of Chemical Sciences, Prof. Institute of General and Inorganic,
Chemistry of Academy of Sciences of the Republic of Uzbekistan
Choriyeva Iklima Yuldosh qizi
Doctor of Chemical Sciences, Prof. Institute of General and Inorganic,
Chemistry of Academy of Sciences of the Republic of Uzbekistan
Savriyeva Dilafruz Doutovna
PhD, Institute of General and Inorganic Chemistry of Academy of
Sciences of the Republic of Uzbekistan, Tashkent, Uzbekistan
Muratov Mirtokhir Mirkhalil ugli
Doctor of Chemical Sciences, Prof. Institute of General and Inorganic,
Chemistry of Academy of Sciences of the Republic of Uzbekistan
Abstract:
This study examines the potential application
of used vegetable oil for the production of lubricating
emulsions. It has been determined that for the
bleaching of used vegetable oil with an acid value (AV)
of 4.0 mg KOH/g, a 4% clay-based adsorbent is
sufficient. The maximum emulsion stability, achieved
after 8 minutes of ultrasonic treatment, corresponds
to a formulation containing 20% vegetable oil, 3%
emulsifier, and 0.2% NaHCO3. Further increasing the
amount of vegetable oil improves the emulsion quality;
however, it also raises production costs.
The American Journal of Applied Sciences
7
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
Keywords:
Vegetable oils, emulsions, droplet size,
ultrasonic treatment, used oils, emulsion stability.
Introduction:
Emulsions are microheterogeneous
systems formed from two immiscible liquids. The size
of the globules ranges from 0.1 to 50 µm. Emulsions
are classified into direct emulsions, i.e., "oil-in-water"
(O/W), where the dispersion medium is water, and
inverse emulsions, "water-in-oil" (W/O), where the
dispersion medium is oil, a non-polar liquid. Emulsions
are further categorized into three types based on the
relative content of the dispersed phase: dilute
emulsions (where the dispersed phase constitutes up
to 0.1%), concentrated emulsions (0.1%
–
74%), and
highly concentrated emulsions (above 74%) [1-3].
When two liquids of different polarities are vigorously
mixed, an emulsion forms due to an increase in
interfacial surface area, leading to enhanced excess
surface energy (σS). This excess energy causes the
coalescence of dispersed phase droplets (globules),
resulting in rapid emulsion breakdown. Therefore,
stabilizers or emulsifiers are commonly used in
practical applications to produce stable emulsions,
chosen based on the type of emulsion being formed [4-
6].
According to Bancroft's rule, the dispersion medium is
the liquid in which the emulsifier dissolves or is better
wetted. To enhance emulsion stability, emulsifiers and
stabilizers are frequently employed. Emulsifiers often
include surface-active agents (surfactants), colloidal
electrolytes,
high-molecular-weight
compounds
(HMWCs), and highly dispersed powders. In O/W
emulsions, hydrophilic substances such as alkali metal
soaps, gelatin, albumin, tannin, protein, chalk, gypsum,
and clay are used, whereas for W/O emulsions,
hydrophobic substances such as multivalent metal
soaps, lanolin, rubber, ceresin, paraffin, and carbon
black are utilized [7,8].
The emulsifying mechanism of surfactants is based on
the adsorption of molecules at the phase boundary,
forming solvation shells around the droplets. Figure 1a
illustrates an O/W emulsion globule obtained by
intensive mixing of toluene and water with the
addition of the emulsifier sodium oleate. In this case,
emulsion stability is ensured by the reduction of
interfacial surface tension and the formation of a
hydration shell. The electric charge of the droplet is
induced by the ionic dissociation of the polar -COONa
group, which enhances emulsion stability. Figure 1b
presents a W/O emulsion globule obtained in the
presence of calcium oleate [9].
Figure 1. Orientation of Emulsifier Molecules at the Phase Interface
The structure of the stabilizing interfacial layer is
complex. The polar groups in the colloidal electrolyte
are oriented toward the aqueous phase, while the non-
polar groups are directed toward the non-polar phase.
The American Journal of Applied Sciences
8
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
As a result, two surfaces are formed with different
surface tensions (σA) and (σB). The emulsifier wraps
around the droplets to prevent coalescence. When the
surface tension between the emulsifier and oil (σA) is
greater than that between the emulsifier and water
(σB), an O/W emulsion is formed
. In this case, for the
oil phase with a high (σA) value, the formation of a
minimal spherical surface is more likely compared to
the aqueous phase. However, if (σA) is lower than (σB),
a W/O emulsion is formed (see Figure 1b). The ratio
between the hydrophilic and lipophilic (hydrophobic)
parts of the emulsifier molecule plays a key role in its
emulsifying ability. This ratio is commonly referred to
as the hydrophilic-lipophilic balance (HLB) [10].
Food-grade lubricating emulsions for coating molds
and sheets are among the imported products in the
republic. Analyzing the composition of these emulsions
has shown that they consist of vegetable oil, water,
emulsifiers, and other components. Currently, the
main vegetable oils produced in the republic include
cottonseed, soybean, and sunflower oil. However, due
to the insufficient production of these oils, they are still
being imported. Therefore, for the production of
lubricating materials, it is necessary to find an
alternative to vegetable oils or explore other less
commonly consumed vegetable oils. One such
alternative is used cooking oils from public catering
services.
This study investigates the feasibility of using used
vegetable oils collected from public catering services to
produce food-grade lubricating emulsions.
METHODS
Used vegetable oils exhibit a color index of 18 red
units, 6 blue units at 35 yellow, with an acid value (AV)
of 3.8 mg KOH/g, and a peroxide value (PV) measured
in mmol of active oxygen per kg.
To analyze the composition of used oil, the bleaching
of used cottonseed oil was carried out. The adsorption
purification was conducted using a traditional method
with up to 5% Pakistani clay adsorbent.
RESULTS AND DISCUSSION
Figure 1. Photographs Before and After Adsorptive Bleaching of Used Cottonseed
Oils
The degree of purification of used cottonseed oil with
clay adsorbents was evaluated based on the acid value
(AV).
The American Journal of Applied Sciences
9
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
Figure 2. Effect of adsorbent quantity on acid value during adsorptive
purification of used cottonseed oil
As shown in Figure 2, an increase in the amount of
adsorbent reduces the acid value from 4.5 to 1.6 mg
KOH/g. However, when the adsorbent quantity
reaches 4%, the acid value (AV) remains practically
unchanged. Therefore, for bleaching used vegetable oil
with an acid value of 4.0 mg KOH/g, a 4% clay-based
adsorbent is sufficient.
The resulting bleached vegetable oil was used as a base
for the production of food-grade lubricating
emulsions. The emulsifiers and stabilizers used in the
formulation are primarily imported. In this case, food-
grade lecithin (Russia) was employed as the emulsifier.
Food emulsions are produced using mechanical
dispersion, spontaneous emulsification, and electro-
physical emulsification methods. The properties of
emulsions
are
evaluated
based
on
several
characteristics, including emulsion dispersity, stability
over time, and the concentration of the dispersed
phase.
Ultrasonic treatment allows for the production of more
stable emulsions compared to mechanical methods.
Frequency oscillations facilitate the formation of ultra-
dispersed emulsions with a wide range of dispersity,
even from complex substances. Therefore, ultrasonic
treatment enhances storage stability, as the particle
size distribution ranges from 1 to 0.5 µm.
During ultrasonic treatment of heterogeneous
systems, two simultaneous processes occur: emulsion
formation at the phase interface and bulk coagulation.
To obtain particles of uniform size, it is crucial to
establish a balance between dispersion and particle
aggregation by determining the threshold value.
Food-grade lubricating emulsions were obtained using
ultrasonic (US) treatment under various conditions.
The characteristics of the resulting emulsions are
presented in Table 1.
Table 1. Dependence of Emulsion Stability on US Treatment Time
Composition of
Lubricating Food
Emulsions
Stability* (%) of
Lubricating Food
Emulsions Derived from
Refined Cottonseed Oil
Over Time (min)
Stability* (%) of
Lubricating Food
Emulsions Derived from
Bleached Waste Oils
Over Time (min)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
A
cid
v
alu
e,
KOH
/g
Adsorbent Quantity , %
The American Journal of Applied Sciences
10
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
4
6
8
10
4
6
8
10
15% Vegetable Oil + 5%
Emulsifier + 0.2%
NaHCO
3
72
81
85
87
68
74
80
82
20% - Vegetable Oil +3%
эмульгатор+0,2%NaHCO
3
75
79
86
87
70
75
78
81
25% - Vegetable Oil +2%
Emulsifier +0,2%NaHCO
3
77
82
90
92
72
76
82
85
*-Stability was determined by centrifugation.
As shown in Table 1, increasing the duration of
ultrasonic (US) treatment enhances the stability of
lubricating
emulsions. However,
the
stability
parameters of emulsions derived from used oils are
lower than those obtained from fresh oils.
Additionally, increasing the oil content in the emulsion
composition improves its stability. In this formulation,
the addition of NaHCO3 helps neutralize free fatty
acids present in vegetable oil, resulting in the
formation of saponified fatty acids that act as
emulsifiers, thereby increasing emulsion stability.
The maximum emulsion stability was achieved with 8
minutes of ultrasonic treatment using a formulation
consisting of 20% vegetable oil, 3% emulsifier, and
0.2% NaHCO3. Further increasing the vegetable oil
content enhances the emulsion quality but also raises
production costs. Based on these findings, the addition
of 20% vegetable oil is sufficient to obtain a stable
lubricating emulsion.
With increasing US treatment time, the probability of
droplet coalescence decreases, while the cavitation
effect ensures uniform distribution of the dispersed
phase droplets. Dispersing the oil phase into the
aqueous phase requires energy to break the interface
between oil and water. During cavitation, ultrasonic
shear forces break large droplets into smaller ones. To
determine the effect of power in the range of 40% to
60% on the size distribution of the dispersed phase, an
investigation was conducted, with the results
presented in Table 2.
Table 2. Dependence Between Ultrasonic Power and Particle Size During US
Treatment
Emulsion obtained
from:
Ultrasonic
Treatment
Power (%)
Duration of Homogenization (min)
2
4
6
8
10
Particle Size of Dispersed Phase (µm):
-From refined
cottonseed oil
40
3
15
25
43
50
50
5
22
35
48
55
60
8
22
41
53
55
- From bleached
waste oils
40
1
11
23
40
45
50
3
18
32
43
52
60
5
20
38
50
52
The American Journal of Applied Sciences
11
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
As shown in Table 2, increasing the duration of
ultrasonic (US) treatment reduces the likelihood of
droplet coalescence in the dispersed phase. During
cavitation, dispersed phase droplets are evenly
distributed in size. With increasing treatment time,
particle size decreases. However, to achieve a highly
dispersed emulsion, sufficient energy is required to
break the oil-water interface. As power increases,
particle size decreases, with the smallest particle size
obtained at 50% power after 8 minutes of treatment.
US processing leads to the breakdown of large particles
due to shear forces generated during cavitation.
Additionally, emulsion stability improves due to
significant energy dissipation at the specified
amplitude.
The effect of US treatment on dispersion was further
examined through microscopic imaging. The images
indicate that oil droplets subjected to US treatment are
nearly homogenized. This further confirms the stability
of these emulsions.
(а)
(b)
Figure 3. Photographs of Emulsion Samples Obtained Using: (a) Conventional
Homogenizer, (b) Ultrasonic Treatment
Thus, with increasing US treatment time, the
probability of droplet coalescence decreases, while the
cavitation effect ensures uniform distribution of the
dispersed phase droplets, enhancing long-term
stability.
CONCLUSION
It was established that the maximum emulsion stability
was achieved after 8 minutes of ultrasonic treatment
with a formulation containing 20% vegetable oil, 3%
emulsifier, and 0.2% NaHCO3. Further increasing the
vegetable oil content improves emulsion quality but
also raises production costs. Based on this, the
addition of 20% vegetable oil is sufficient for obtaining
a stable lubricating emulsion.
REFERENCES
Antipova L.V., Faustova E.V., Uspenskaya M.E.,
Storublevtsev S.A. Emulsions in Food Production
Technology // Advances in Modern Natural Sciences.
2012. No. 6. P. 129.
Baronov V.I., Kulenko V.G., Fialkova E.A. Vortex
Homogenization as a Means of Obtaining High-Quality
Food Emulsions // Economics. Innovations. Quality
Management. 2015. No. 1 (10). Pp. 19
–
20.
Shanmugam A., Ashokkumar M. Ultrasonic
Preparation of Stable Flax Seed Oil Emulsions in Dairy
Systems
–
Physicochemical Characterization // Food
Hydrocolloids. 2014. Vol. 39. Pp. 151
–
162. DOI:
https://doi.org/10.1016/j.foodhyd.2014.01.006.
Baranov V.Ya., Frolov V.I. Study of Emulsion Properties
// Methodological Guidelines for the Laboratory
Practicum in the Course "Physical and Colloid
Chemistry". Moscow, 2007. 19 p.
Baranov V.Ya., Lyubimenko V.A. Practicum on the
Course "Physical and Colloid Chemistry".
–
Moscow:
GANG named after I.M. Gubkin, 1992.
–
75 p.
Frolov Yu.P. Course in Colloid Chemistry. Surface
Phenomena and Disperse Systems: A Textbook for
Universities.
–
Moscow: Khimiya, 1989.
–
464 p.
Vinogradov
V.M.,
Vinokurov
V.A.
Formation,
Properties, and Methods of Destruction of Petroleum
Emulsions: Methodological Guidelines for Students of
Chemical Engineering Specialties.
–
Moscow: GANG
named after I.M. Gubkin, 1996.
–
32 p.
Kapustin S.V., Krasulya O.N. Application of Ultrasonic
Cavitation in the Food Industry // Interactive Science.
2016.
No.
2.
Pp.
101
–
103.
DOI:
The American Journal of Applied Sciences
12
https://www.theamericanjournals.com/index.php/tajas
The American Journal of Applied Sciences
https://doi.org/10.21661/r-18916.
Kyuregyan G.P., Komarov N.V., Kyuregyan O.D.
Application of the Cavitation Effect in the Production
of Long-Shelf-Life Emulsions for Various Industries //
Bulletin of the All-Russian Scientific Research Institute
of Fats. 2015. No. 1
–
2. Pp. 29
–
32.
Muratov. M.M., Kurniawan T.A., Eshmetov R.J.,
Salikhanova D.S., Eshmetov I.D., Adizov B.Z.,
Khandamov D.X., Madaminov B., Choo W.O./
Promoting sustainability: Micellization and surface
dynamics of recycled monoethanolamine surfactants.
Journal of Molecular Liquids. 414 (2024) 126010.
