INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 05,2025
Journal:
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page 879
UDK 661.728.
WASTEWATER TREATMENT OF CELLULOSE PRODUCTION BASED ON
LOCAL RAW MATERIALS
R.S. Sayfutdinov, U.D. Mukhitdinov, D.S. Kenjaeva
Tashkent of Chemical Technology Institute
Currently, the cotton industry is associated with a significant consumption of water from
natural sources, including low-grade lint, cotton wool, and other cellulose used in textiles. In
production, 1 ton of pulp and paper products consumes 100 or more liters of water, of which
at least 30% is fresh water, which leads to an increase in the amount of wastewater [1].
The advantages of producing cotton pulp from annual plants instead of perennial plants are
particularly important due to the fact that they use much less water, do not use toxic chlorine,
sulfur and other reagents in the production [2].
It was previously announced by the authors that wastewater can be purified and reused in
cellulose production plants [3]. The fact that drinking water can be reduced by 5-10 times due
to repeated reuse of wastewater shows how urgent the work is in times of water scarcity.
In order not to harm the environment, it is necessary to clean the waste water up to the values
of limit substance amount (PDK), at present, it is necessary to further increase the
requirements for the quality of waste water of the enterprises.
In wastewater treatment practice, it is necessary to widely use membrane separation methods,
which have such advantages as high purification levels in closed-loop water supply,
compactness of equipment, wide automation, and low cost of treatment compared to
traditional treatment facilities [4].
The following requirements for wastewater entering the membrane treatment are: initial
purification from large dispersed suspended solids; pH value from 3 to 12; temperature
should not exceed the level at which membrane separation occurs.
This article presents the results of research on the reuse of wastewater from the pulp industry
in the process of obtaining cotton pulp after treatment using mechanical and physicochemical
methods.
The object of the study was wastewater from the technology of cellulose extraction from low-
grade lint in oxygen-alkaline high-temperature (130
0
С) conditions. The composition of this
wastewater includes: salts of fatty acids, hemicellulose, resins, the presence of.
The chemical oxygen demand (COD
5
) determined by the arbitration method was 9700 mg-
Og/l, free alkalinity 5.0 mg-eq/l, pH>12.
Filtration followed by neutralization and coagulation was used for the initial treatment of the
investigated wastewater.
The wastewater was filtered under vacuum in a quartz-sand filter. According to the amount of
sediment retained in the filter, it was determined that the concentration of suspended
substances in wastewater is 1 g/l.
The wastewater was neutralized due to its high pH value. Therefore, concentrated sulfate
60% nitric acid was added to it until it reached pH=6.7 and pH=9.0. It uses water coagulants
that are widely used in wastewater treatment practice: aluminum sulfate (AI
2
(SO
4
)
3
*18H2O)
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 05,2025
Journal:
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page 880
and iron sulfate (II) (FeSO
4
*7H
2
O). Therefore, in order to reduce the consumption of
reagents, it is necessary to carry out the coagulation process when the pH value is in the
optimal range: when using AI
2
(SO
4
)
3
*18H
2
O - pH=4.5-7; when using FeSO
4
-7H
2
O - pH=8-
10 [5].
The results of wastewater neutralization are presented in table 1.
Table 1
Changes in wastewater (COD5) and pH values after neutralization
The analysis of the COD
5
values in Table 1 shows that the neutralization of wastewater
can be accompanied by oxidative processes that lead to a decrease in the COD
5
value. For
example, the COD
5
of the wastewater in the initial state decreased to 1230 and 1280 after
neutralization when HNO
3
and H
2
SO
4
were used as neutralizing agents, respectively.
Then, the wastewater under study was treated using coagulants in the form of 10% aqueous
solutions - AI
2
(SO
4
)
3
*18H
2
O and iron sulfate (II) FeSO
4
*7H
2
O - to remove finely dispersed
mineral and organic components.
The wastewater sample that had undergone the neutralization stage was added with
solutions of AI
2
(SO
4
)
3
*18H
2
O and FeSO
4
*7H
2
O, recalculated according to A1
3+
and Fe
3+
,
until the concentrations reached 50, 100, 200, 300, 400, 500 mg/l. The samples were mixed
on a magnetic stirrer for 2 minutes and left to stand for 2 hours. During this time, the
appearance of particles and their sedimentation were observed in samples №1 and №3, whose
concentrations were recalculated according to A1
3+
and Fe
3+
were 500 mg/l (table 2).
The data in table 2 show that the type of neutralizing agent affects the purification process in
which coagulants are used. The coagulation process was found to be effective when
AI
2
(SO
4
)
3
*18H
2
O was added to the wastewater at a pH of 6.7. Under these conditions, the
process proceeds with the clarification of the wastewater. The degree of purification was
38.8% compared to the previous stage (COD5), which corresponds to a total degree of
purification of 71.4%. The initial purified water obtained by this method meets the
requirements for wastewater undergoing membrane purification.
Table 2
Changes in the pH and COD values of wastewater after the addition of coagulants
until a concentration of 500 mg/l is reached, recalculated in accordance with A1
3+
and
Fe
3+
Neutralizing agents
Wastewater pH
Amount of waste water
(COD
5
), mg O
2
/l
Nitric acid (HNO
3
)
6.7
1370
9.0
1230
Sulfuric acid (H
2
SO
4
)
6.7
1460
9.0
1290
Alkali and alkali (NaOH)
6.7
2180
Example Neutralizing agents
Initial pH of
wastewater
Coagulant
(COD),
mg-O
2
/l
1
HNO
3
6,7
Al
2
(SO
4
)
3
*18Н
2
О 427
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 05,2025
Journal:
https://www.academicpublishers.org/journals/index.php/ijai
page 881
The cleaning efficiency (COD
5
) was determined by the change in value and the light
transmission coefficient determined in a cuvette with a layer thickness of 1 cm in a
photoelectrocalorimeter at a wavelength of 360 nm.
As a result, after the filtration process, the following parameters were achieved: (COD
5
) 1360
mg O
2
/l, the light transmission coefficient was 98.5%, which means that the purification level is
93.5%.
Sodium ions dissolved in wastewater were sorbed using N-form cations. The results are
presented in table 3.
Table 3
Sorption of Na
+
ions from wastewater by ion exchange
Cationite
Static exchange capacity of cation
exchangers for Na
+
ions, mg-eq/g Partition coefficient, ml/g
KU-2×8
5.4
184
KU-1
3.1
110
Along with the ion-exchange capacities of ion exchangers, the rate of ion-exchange - the
kinetics of the process - is also of practical importance. The rate of ion-exchange in cation
exchangers was characterized by the amount of sodium ions (mg-eq/g) absorbed from 0.1 N
NaCl solutions under static conditions per unit of time (minute). In this study, KU-2×8 and KU-
1 cation exchangers used in industry were studied. The static exchange capacities of cation
exchangers in the H-form in 0.1 N NaCl solution were determined: KU-2×8 - 5.4 mg-eq/g, KU-
1 - 3.1 mg-eq/g.
From
the
kinetic curves
(Fig. 1), it
can be seen
that
the
saturation
level of the KU-2×8 cationite during the sorption process for 30 minutes was 2.8 mg-eq/g, while
that of the KU-1 cationite was 1.6 mg-eq/g. In order to study in detail the mechanism of
2
H
2
SO
4
6,7
534
3
HNO
3
9,0
FeSО
4
*7Н
2
О
261
4
H
2
SO
4
9,0
319
20
40
60
80
0
0.2
0.4
0.6
0.8
1
А
2
1
τ, дақ.
Fig. 1. Sorption rate of sodium ion in cationites.
Cationites: 1 – КU-2×8, 2 – КU-1.
100
INTERNATIONAL JOURNAL OF ARTIFICIAL INTELLIGENCE
ISSN: 2692-5206, Impact Factor: 12,23
American Academic publishers, volume 05, issue 05,2025
Journal:
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page 882
exchange of hydrogen ions for sodium ions, the well-known time-dependent ion-exchange rate
relationships were used: lg(1–A)=k
1
τ – for thin-layer kinetics; and A=k(τ)
1/2
– for gel kinetics;
where A is the corresponding amount of ions sorbed on the cationite – the degree of equilibrium
for solution systems (dynamic method), but under static conditions their solutions in a limited
volume are used in large ratios of the liquid phase to the cationite (in our conditions Sphase:
Qphase = 1000 ml: 1 g.). τ – time, minutes. Based on experimental and computational data,
kinetic curves were constructed. When constructing the graph of the dependence of lg(1–A) – τ,
the experimental points do not lie on a single straight line for the studied cation exchangers.
Undoubtedly, the internal diffusion mechanism of kinetics has a dominant effect on the sorption
rate. The limiting effect of gel kinetics can be assessed both by the coordinates of the
dependence of A on
t
for the initial stages of the process, and by the curves of the
dependence of Bt on τ for the entire process, where A<0.4, where the experimental points lie on
a straight line to a first approximation, Bt is a non-dimensional quantity and is a function of A.
Conclusion
According to the results of the conducted studies, the purification of wastewater generated
during the production of cellulose by the oxygen-alkali cooking method using the ion-exchange
method after the initial filtration, neutralization and coagulation stages is recommended for
widespread use in the future in a closed water circulation system for the production of cellulose
from cotton raw materials.
Literature:
1. Mirkamilov T.M. Cotton cellulose technology. // Tashkent. Fan. 1996. - P.272.
2. Mukhitdinov U.D., Saifutdinov R.S. Study of the influence of oxygen-alkaline cooking
parameters on the quality indicators of cellulose obtained from cotton linters. //
Composition of materials. 2018. No. 2. Tashkent. - P.88-91.
3. Saifutdinov R.S., Tillashaykhov M.S. Study of the process of obtaining cellulose with the
reuse of spent liquor. // Collection of scientific papers of TashKhTI, 1993. Issue 2, P.23-26.
4. Turobjonov S.M., M.M. Niyozova, T.T. Tursunov, H.M. Pulatov. Technology of industrial
waste recovery. // Textbook. Tashkent. Publishing house of the National Society of
Philosophers of Uzbekistan. 2011. 184 p.
5.
Mutalov Sh.A., Tursunov T.T., Pulatov H.L., Zainutdinova V.G., Usmonkhodjaeva I.T.
Purification facilities and devices. // Textbook. Tashkent. 2016. – 300 p.
