Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
Research Article, Issue 1
Analytical Methods in Environmental Chemis try Journal
Journal home page: www.amecj.com/ir
AMECJ
Adsorption behavior of Crys tal Violet dye in aqueous
solution using Co+2 hectorite composite
as adsorbent surface
Ahmed Jaber Ibrahima,*
a Scientic Research Center, Al-Ayen University, ThiQar 64011, Iraq
ABSTRACT
This s tudy focused on the adsorption behavior of the cationic Crys tal
Violet (CV) dye from aqueous solutions using a Co+2‒hectorite
composite as an adsorbent surface. The initial and equilibrium CV dye
concentrations were determined using a UV-Vis spectrophotometer. The
results were discussed and presented for the impacts of pH, primary CV
dye concentration, composite dosage, and temperature. The optimum
conditions were found for eliminating Crys tal Violet dye from the
aqueous solution at a pH 4, ideal temperature 293 K, and 0.5 g L-1
of composite dose. The pseudo-second-order kinetic, intraparticle
diusion analyzed the tes ts’ data and lm diusion models. Each
model’s dening features have been identied, and these models were
in good agreement and in charge of regulating the adsorption reaction.
The adsorption operation was also thermodynamically examined to
determine thermodynamic variables such as Gibbs free energy (ΔGo),
entropy (ΔSo), activation energy (Ea), and enthalpy (ΔHo). The negative
value of Gibbs free energy (ΔGo) and enthalpy (ΔHo) indicated that
the adsorption process was a spontaneous and exothermic reaction.
While the activation energy (Ea) data which fell within the normal
range for physisorption, was discovered to be 22.434 kJ mol-1. This
result proved that physical adsorption occurs between the CV dye and
the adsorbent surface (Co+2‒hectorite composite).
Keywords:
Adsorption,
UV-Vis spectrophotometer,
Crys tal violet,
Isotherm,
Thermodynamics,
Kinetics
ARTICLE INFO:
Received 15 Nov 2022
Revised form 1 Feb 2023
Accepted 25 Feb 2023
Available online 30 Mar 2023
*Corresponding Author: Ahmed Jaber Ibrahim
Email: ahmed.jibrahim@alayen.edu.iq
https://doi.org/10.24200/amecj.v6.i01.219
------------------------
1. Introduction
Although synthetic dyes are widely utilized in the
textile sector, 20 to 40 % of these pigments s till
end up in euents [1-3]. The majority of pigments
contain hazardous and cancer-causing subs tances.
They also pose a signicant hazard to the health
of people and the environment since they are
resis tive and so s table in a recovering ecosys tem [4].
Therefore, before the dye-containing was tewater
is released into the environment, the dyes mus t
be removed to safeguard persons and ecosys tems
from pollution. The elimination of contaminants
in plas tics, pulp, dyes tus, paper euents, and
textiles has been documented using several physical,
chemical, and biological decolorization processes.
However, these sectors had only welcomed a small
number of them [5–18]. Adsorption is the bes t
option for producing the mos t signicant outcomes
among the several dye removal procedures since it
may be used to eliminate specic groups of chemical
contaminants from aqueous solutions. Adsorption
is preferable to compete for sys tems for utilizing
recycled water regarding low cos t, formability and
s tyling simplicity, ease of use, and sensitivity to
harmful contaminants. According to several s tudies
6Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
[19,20], activated charcoal and polymer resins are
the bes t adsorbents for eliminating pigments from
suitably saturated sewage. The adsorption capability
of some reactive dyes by activated carbon is known
to be relatively poor. The sewage treatment process
utilizing clay-basic [21], AC-ZnO nanos tructure [22],
cotton [23], Ultraviolet-activated sodium perborate
[24], halloysite nanotubes [25], electrospun nanober
mat [26], chitosan [27], and natural zeolite-basic
[18] has thus been the subject of Previous s tudies.
Because of their large surface area and molecular
sieve composition, Clay-based materials are
ecient organic cation pollutant adsorbents [3]. The
generality widely utilized layered silicate is hectorite.
Tetrahedral subs tituted and octahedral subs tituted
are the two s tructural kinds. Hectorite is an excellent
adsorbent for eliminating dye from comparatively
saturated was tewater. This is attributed to the fact that
hectorite has a unique s tructure with internal channels
that permits the passage of solutes and bonded organic
and inorganic ions into the s tructure of hectorite.
This article sugges ted using a Co+2-hectorite
composite as an Adsorbent surface to absorb crys tal
violet (CV) dye from aqueous solutions. The results
were discussed and presented for the impacts of pH,
primary CV dye concentration, composite dosage,
and temperature. The data from the tes ts were
analyzed by the pseudo-second-order kinetic, intra-
particle diusion, and lm diusion models. Each
model’s dening features have been identied. The
adsorption operation was also thermodynamically
examined to determine thermodynamic variables
such as Gibbs free energy (ΔGo), entropy (ΔSo),
activation energy (Ea), and enthalpy (ΔHo).
2. Materials and Methods
2.1. Ins truments
Thermos tatic Controlled shaker (SHKE4000, Thermo
Fisher Scientic; USA), UV-Vis spectrophotometer
(UV-3600i Plus, Shimadzu, Japan), pH meter
(model 744 Metrohm; Germany), Ultrasonic
cleaner (WUC-A 1,2- Witeg Labortechnik GmbH;
Germany), Mechanical s tirrer (Euros tar 60 digital,
IKA; China) and vacuum drying oven (Model VD
56-BINDER GmbH; Germany) were used.
2.2. Chemicals
All chemicals with high purity were purchased
from the original Company. The chemicals such as,
Crys tal Violet (CV) dye (C25H30ClN3, Mwt 407.986
dalton, CAS N.: 548-62-9, Tokyo Chemical
Indus try Co., Japan; Fig. 1), hectorite (Na0.3(Mg,
Li)3Si4O10(OH)2, Mwt 360.58 dalton, CAS N.:
12173-47-6, Spectrum Chemical Co., USA),
hydrochloric acid 37% (HCL, CAS N.: 7647-
01-0, Sigma-Aldrich Chemie GmbH Co., USA),
and Cobalt chloride (CoCl2, CAS N.: 7646-79-9,
American Elements Co., USA) were prepared for
this research.
Fig. 1. The s tructural formula of Crys tal Violet dye
2.3. Preparation of Co+2-hectorite composite
The ion-exchanged technique was used to prepare
the sorbent in a single s tep. Two grams of hectorite
were mixed with 0.2 liters of dis tilled water and
swirled for 2 hours. Using hydrochloric acid (1M,
HCl) solution, the colloidal dispersion’s pH was
reduced to 6. Cobalt chloride (CoCl2) solution
was added in the calculated amount while s tirring
for 8 hours. The nal dispersion was cleaned by
dis tilled water. At 80oC, the product was dried after
centrifugation.
2.4. Adsorbate
Crys tal Violet (CV) dye was used as the model gues t
to examine the adsorption capability. Using a UV-Vis
spectrophotometer with a range of 200 - 800 nm, the
7
Adsorption of CV Dye by Cobalt-Hectorite Composite Ahmed Jaber Ibrahim
maximum wavelength of 585 nm was determined,
which corresponds to the highes t absorption of the
dye solution, as shown in Figure 2. To create the
s tock solution, dis tilled water was used to dissolve a
carefully weighed quantity of CV dye. The solutions
for adsorption tes ting were made at the necessary
concentrations by applying serial dilutions to the
s tock solution. Firs t, a calibration curve for CV dye
was drawn. In kinetic and thermodynamic s tudies,
this curve was used to translate data on concentration
from absorbance measurements.
2.5. Adsorption process
At various temperatures, adsorption s tudies were
conducted in a controlled thermos tatic shaker.
Up until the point of equilibrium, the shaking
persis ted. The initial and equilibrium CV dye
concentrations were determined using a UV-Vis
spectrophotometer. The adsorption capability of the
adsorbent was determined using these data. It was
possible to determine the quantity of CV adsorbed
(qe) at equilibrium. The mass balance is shown in
Equation 1.
qe=v(C0- Ce )/W (Eq.1)
Where v is the volume of dye solution used (L), is
the primary dye concentration in the liquid phase
(g L-1), is the liquid phase dye concentration at
equilibrium (g L-1), and W is the mass of sorbent
utilized (g). By adding 0.03 g sorbent at various
temperatures to 0.060 L of crys tal violet solution
(0.150 g L-1), kinetic inves tigations were conducted.
The liquid phase crys tal violet concentration was
monitored at predetermined intervals.
3. Results and Discussion
3.1. The inuence of solution pH
The inuence of solution pH for the elimination
of CV dye by Co+2-hectorite complex was s tudied
in the range of 2–12 under the conditions: 0.150
g L-1 CV dye concentration, 0.5 g L-1 Composite
dosages, 293 temperature, and 1 hour Contact
time). The implies of the repeated experimental
outcomes are plotted in Figure 3. The experimental
results showed that the degree of adsorption of CV
dye on the Co+2-hectorite composite reached 95%
when the pH of the solution was 4. Therefore, the
optimal pH was considered to be 4, which achieves
the maximum adsorption of CV dye. On this basis,
the remainder of the subsequent tes ts were carried
out at this optimum pH value. Other inves tigators
Fig. 2. The UV-Vis spectrum of Crys tal violet dye
8
have shown a tendency similar to the adsorption
process of the Congo red azo dye as a function of
pH [28].
3.2. Eect of sorbent composite dose
Between 0.5 and 1.5 g L-1 of Co+2-hectorite
composite, the dose was tes ted under the
conditions: (primary CV dye concentration 0.5 g
L-1, 0.6 g L-1, 0.7 g L-1 , ph=4, 293 K temperature
and 8 hour Contact time) to see how it aected CV
dye adsorption. Figure 4 of the ndings indicates
a decrease in with an increase in Co+2-hectorite
dosage. Because a greater adsorbent dose decreases
the adsorption sites’ unsaturation, there is relatively
less adsorption at larger adsorbent doses. CV dye
can quickly arrive at the adsorption locations, and
the qe rises when the amount of adsorbent is modes t.
Because less of the adsorbent’s adsorptive capacity
is being utilized with an increase in adsorbent
amount, the correlating increase in adsorption
reaction per unit clus ter is decreased.
Higher adsorbent dosages caused particle
aggregation, reducing the overall surface area
and the multitude of active adsorption locations.
The highes t CV dye adsorption in this research
was accomplished at a Co+2-hectorite dose of
0.5g remaining trials were carried out at this
concentration.
0.0 0.5 1.0 1.5 2.0
0.2
0.3
0.4
0.5
0.6
sorbent compsite dose (g.L
-1
)
qe (g.g
-1
)
0.5 g.L
-1
0.6 g.L
-1
0.7 g.L
-1
0246810 12 14
0.86
0.88
0.90
0.92
0.94
0.96
0.98
Initial pH level
Rate of adsorpation
Fig. 3. Inuence of pH of CV dye adsorption on Co+2-hectorite composite
Fig. 4. Eect of sorbent composite dose on CV dye adsorption
Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
9
3.3. Eect of primary crys tal violet (CV) dye
concentration and temperature
It is unclear how varied CV dye concentrations
aect how well Co+2-hectorite composite removes
CV because the euent from various indus tries
may include varying amounts of dye. This s tudy
examined the adsorption of concentrations of 0.100,
0.125, 0.150, 0.175, and 0.200 g L-1 CV dye for
the Co+2‒hectorite composite. The duplicate data’s
means are shown in Figure 5, which shows that the
concentration of CV dye has a signicant inuence
on the adsorption capability of the Co+2-hectorite
composite. Based on the data shown in Figure 5,
the qe of Co+2-hectorite rose at various temperatures
when the primary CV dye concentration was raised.
This is explained by the reality that free adsorption
locations are accessible at the s tart of the tes t and
by the fact that there was a more eective mass
transfer rate during the rs t contact period when
the CV dye concentration was at its highes t.
The impact of temperature on the CV dye adsorption
equilibrium on the Co+2-hectorite surface is also
depicted in Figure 5. For a primary concentration of
0.100-0.200 g L-1, it can be seen that the qe declined
as the temperature rose, indicating an exothermic
process. Though the impact of temperature on the
adsorption equilibrium was negligible at the low
s tarting concentration of CV dye (0.100 g L-1), it
was s till present.
3.4. The inves tigation of intra-particle diusion
and lm diusion
To determine whether external lm diusion or
intraparticle diusion aected the removal rate,
the Weber-Morris kinetic model was used s as
Equation 2[29].
qt=Kidt0.5 + C (Eq.2)
where represents the removal capacity (mg g-1) at
time(t), Kid represents the intra-particle diusion
rate cons tant (mg per g min0.5), and C represents a
cons tant whose value is proportionate to the limit
layer (mg g-1).
When the adsorption sys tem corresponds with the
intra-particle diusion mechanism, a plot of qt
versus t0.5 should have a s traight line with a slope of
Kid and an intercept of C, according to Equation 2.
Figure 6 shows a plot of the means of the replicated
experimental outcomes. There are two dis tinct
zones in Figure 6. The rs t s traight and the second
linear sections are attributed to macro- and micro-
0.10 0.15 0.20
0.30
0.35
0.40
0.45
0.50
CV primary concentration (g.L-1)
qe (g.g-1)
293 K
303 K
313 K
Fig. 5. Inuence of primary dye concentration and temperature on the adsorption process
Adsorption of CV Dye by Cobalt-Hectorite Composite Ahmed Jaber Ibrahim
10
pore diusion, respectively. The immediate use of
the adsorbing locations on the adsorbent supercial
is blamed in the rs t section. The second section’s
phenomenon is linked to an extremely slow CV
diusion into the leas t accessible adsorption
sites—the micro-pores—from the surface lm.
Additionally, this promotes the sluggish quiet rate
of adsorbate movement from the liquid s tage to
the surface of the adsorbent. The mass transfer rate
variance between the adsorption reaction’s rs t and
end phases explains why the s traight line deviates
from the original line. The s traight line’s continued
departure from the point of origin sugges ts that pore
diusion is not the lone rate-limiting process [30].
To support the above ndings, the intra-particle diusion
coecients (Dp) were es timated by Equation 3.
(Eq.3)
where r0 (m) represents the mean radius of the
adsorbent particles and t0.5 (min) the time needed to
fulll half of the adsorption.
The rate-limiting phase will be intra-particle
diusion, referring to Sushanta et al. [31], if the
predicted intra-particle diusion coecient (DP)
level is in the scope 10-15-10-18 m2 per S. According
to Table 1, which was used in this inves tigation,
the computed DP level varied from 1.65x10-14 to
2.47x10-14 m2 s-1 at various temperatures, implying
that intra-particle diusion reaction is not the
primary process limiting CV dye adsorption onto
Co+2-hectorite surface.
Fig. 6. Scatter plot of qt versus t0.5 for adsorption of CV dye on Co+2-hectorite composite
at s tudied temperatures
246810
0.20
0.25
0.30
0.35
0.40
t0.5
qt (g.g
-1
)
293 K
303 K
313 K
Table 1. The adsorption process’s lm diusion coecient (DF) and intra-particle diusion coecients (DP)
at the temperatures s tudied
Temperature (k) DP (m2 S-1) DF (m2 S-1) ro(m)
293 77.44 1.65 x 10-14 3.44 x 10-13
6.54 x 10-4
303 63.36 2.02 x 10-14 4.21 x 10-13
313 51.87 2.47 x 10-14 5.63 x 10-13
Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
11
Equation 4 has been used to compute the lm
diusion coecients (DF), to examine the
adsorption kinetics reactions.
(Eq.4)
Where CS is the concentration of adsorbate in the
solid phases, Cl is the concentration of adsorbate in
the liquid phase, and r0 and t0.5 share the identical
meaning as earlier, and d is the lm thickness (10-5m)
[31]. The computed lm diusion coecient (DF)
value will fall between 10-10 and 10-12 m2 per second
if the lm diusion reaction is the rate-limiting
s tep’s controlling factor. The predicted levels of
DF were discovered to be in the arrange of 10-13
m2s-1 (Table 1), indicating that the lm diusion
reaction was not the lone phase in the adsorption
process that was rate-limiting. Intra-particle and
lm diusions in this s tudy served to regulate the
kinetic process. The kinetic reaction was governed
by lm diusion since the CV concentration was
high at the beginning of the adsorption process. CV
molecules s tarted to diuse inside Co+2-hectorite
when they were adsorbed on the surface of the
composite, and the adsorption reaction was what
controlled this.
3.5. Thermodynamics s tudy
The pseudo-second-order [32] model has been
inves tigated about kinetic modeling to determine
the adsorption mechanism (Equation 5).
(Eq.5)
Where qe is the equilibrium adsorption capability
(g.g-1), k2 is the pseudo-second-order adsorption
rate cons tant (g min g-1), and qt is the amount
of CV adsorbed at time t (g g-1). To determine
rate parameters, the s traight line plots of t/qt vs.
t for the pseudo-second-order models have also
been inves tigated (Fig. 7). Table 2 contains the
correlation coecients r2, k, and qe at numerous
temperatures. The Arrhenius equation (Eq. 6) can
express the pseudo-second-order rate cons tants as
a temperature performance.
ln k = ln A - Ea/RT (Eq.6)
Where k is the rate conant, A is the frequency
coecient, Ea is the activation energy, R is the gas
conant, and T is the temperature in Kelvin.
Figure 8 shows a visualization of the means of the
replicated experimental outcomes.
050 100
0
100
200
300
400
t (min)
t/qt
293 K
303 K
313 K
Fig. 7. The pseudo-second-order kinetics model for the adsorption of CV dye onto Co+2-hectorite composite
at s tudied temperatures
Adsorption of CV Dye by Cobalt-Hectorite Composite Ahmed Jaber Ibrahim
12
The Ea is calculated using Equation 6 (Table 2).
The size of the activation energy gives a clue as
to the primary kind of adsorption, either chemical
or physical. Physisorption processes typically
have activation energies between 5 and 40 kJ mol-
1, whereas greater activation energies (between
40 and 800 kJ.mol-1) point to chemisorption. The
dispersive interaction between the crys tal violet
and the Co+2-hectorite surface implies it. The Gibbs
free energy (ΔGo), enthalpy change (ΔHo), and
entropy change (ΔSo), which are thermodynamic
characteris tics, have been calculated to assess
the viability and exothermic characteris tic of the
adsorption reaction. Equation 7 relates the process’s
change in Gibbs free energy to the equilibrium
cons tant (k).
(Eq. 7)
The below formula shows how the s tandard free
energy change at cons tant temperature is also
correlated with enthalpy and entropy changes
(Eq. 8).
(Eq. 8)
Table 2. The Arrhenius activation energy (Ea) and pseudo-second-order kinetics parameter values
for the adsorption process at temperatures s tudied
Temperature (k) (kJ mol-1) r2qe (g g-1) k2
293
22.434
0.9996 0.335 2.087
303 0.9954 0.317 2.794
313 0.9965 0.302 3.587
0.0028 0.0029 0.0030 0.0031 0.0032 0.0033
-7.4
-7.2
-7.0
-6.8
-6.6
-6.4
-6.2
1/T
lnk2
Fig. 8. Arrhenius Scatter plots for the adsorption of CV dye onto Co+2-hectorite at s tudied temperatures
Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
13
The slope and intercept of Scatter plots of lnK vs
1/T are utilized to evaluate the levels of ΔGo and
ΔSo (Fig. 9). Table 3 contains the obtained values.
Indicating the viability and spontaneity of the CV
adsorption reaction on the Co+2-hectorite surface,
the Gibbs free energy (ΔGo) levels were observed
to be decreasingly negative with temperature. It is
discovered that the enthalpy change (ΔHo) values
are negative, indicating the exothermic character
of the adsorption process. The fact that the (ΔHo)
value is less than 40 kJ.mol-1 shows that the crys tal
violet adsorption by the composite of Co+2-hectorite
is physisorption. The results from the current s tudy
are comparable to those from Xia’s s tudy [28] on
the adsorption reaction of congo red azo dye from
aqueous solution by ODA-hectorite and CTAB-
hectorite as adsorbent surfaces.
4. Conclusion
The results of this inves tigation demons trate
the eciency of Co+2-hectorite composite as an
adsorbent surface for eliminating Crys tal Violet
(CV) dye from aqueous solutions. The elimination
of CV worked bes t at a pH of 4. The ideal
temperature and composite dose were 293oK and
0.5 g L-1, respectively. The experimental results
and the pseudo-second-order kinetic model were in
good agreement, as indicated by the s traight lines
in t/qt vs t plots. Intra-particle and lm diusions
were in charge of regulating the adsorption reaction.
The exothermic and spontaneous response of CV
adsorption on Co+2-hectorite composite is revealed
by evaluating the thermodynamic parameters. The
activation energy for adsorption, which fell within
the normal range for physisorption, was discovered
Table 3. Thermodynamic variables for the adsorption process
Temperature (k)Distributioncoecient(k) ΔGO
(kJ mol-1)
ΔHO
(kJ mol-1)
ΔSO
(kJ mol-1)
293 4.654 -3.745
-31.546 -94.883
303 3.324 -2.926
313 2.067 -1.768
0.0028 0.0029 0.0030 0.0031 0.0032 0.0033
0.0
0.5
1.0
1.5
2.0
1/T
lnk
Fig. 9. Scatter plot of lnK vs. 1/T for CV dye adsorption onto Co+2-hectorite composite.
Adsorption of CV Dye by Cobalt-Hectorite Composite Ahmed Jaber Ibrahim
14
to be 22.434 kJ mol-1. The outcomes would benet
the design of was tewater treatment facilities that
remove the dye.
5. Acknowledgements
The s tructural formula of the Physical Chemis try
Lab., Chemis try Department, College of Education
for Pure Science (Ibn-al Haitham), University of
Baghdad, supports this research.
6. References
[1] F. Kooli, S. Rakass, Y. Liu, M. Abboudi,
H.O. Hassani, S.M. Ibrahim, F.
Wadaani, R. Al-Faze, Eosin removal by
Cetyl trimethylammonium-Cloisites:
influence of the surfactant solution type
and regeneration properties, Mol., 24
(2019) 3015. https://doi.org/10.3390/
molecules24163015.
[2] F.M. Valadi, A. Ekramipooya, M.R.
Gholami, Selective separation of Congo
Red from a mixture of anionic and cationic
dyes using magnetic-MOF: Experimental
and DFT s tudy, J. Mol. Liq., 318 (2020)
114051. https://doi.org/10.1016/j.
molliq.2020.114051.
[3] P. S. Kumar, G. J. Joshiba, C. C. Femina, P.
Varshini, S. Priyadharshini, M. A. Karthick,
R. Jothirani, A critical review on recent
developments in the low-cos t adsorption
of dyes from was tewater, Desalin. Water
Treat., 172 (2019) 395-416. https://doi.
org/10.5004/dwt.2019.24613.
[4] S. Benkhaya, S. M’rabet, A. El Harfi,
Classifications, properties, recent synthesis
and applications of azo dyes, Heliyon, 6
(2020) e03271. https://doi.org/10.1016/j.
heliyon.2020.e03271.
[5] G. Crini, E. Lichtfouse, Advantages and
disadvantages of techniques used for
was tewater treatment, Environ. Chem.
Lett., 17 (2019) 145-155. https://doi.
org/10.1007/s10311-018-0785-9.
[6] S. Samsami, M. Mohamadizaniani, M.H.
Sarrafzadeh, E.R. Rene, M. Firoozbahr,
Recent advances in the treatment of
dye-containing was tewater from textile
indus tries: Overview and perspectives,
Proc. Safe. Environ. Prot., 143 (2020)
138-163. https://doi.org/10.1016/j.
psep.2020.05.034.
[7] E. Routoula, S.V. Patwardhan, Degradation
of anthraquinone dyes from effluents:
a review focusing on enzymatic dye
degradation with indus trial potential,
Environ. Sci. Technol., 54 (2020) 647-664.
https://doi.org/10.1021/acs.es t.9b03737.
[8] A. Tkaczyk, K. Mitrowska, A. Posyniak,
Synthetic organic dyes as contaminants
of the aquatic environment and their
implications for ecosys tems: A review, Sci.
Total Environ., 717 (2020) 137222. https://
doi.org/10.1016/j.scitotenv.2020.137222.
[9] L. Largitte, R. Pasquier, A review of the
kinetics adsorption models and their
application to the adsorption of lead by
an activated carbon, Chem. Eng. Res.
Desi., 109 (2016) 495-504. https://doi.
org/10.1016/j.cherd.2016.02.006.
[10] C. Santhosh, V. Velmurugan, G. Jacob,
S.K. Jeong, A.N. Grace, A. Bhatnagar,
Role of nanomaterials in water treatment
applications: a review, Chem. Eng.
J., 306 (2016) 1116-1137. https://doi.
org/10.1016/j.cej.2016.08.053.
[11] M. Berradi, R. Hsissou, M. Khudhair, M.
Assouag, O. Cherkaoui, A. El Bachiri, A.
El Harfi, Textile finishing dyes and their
impact on aquatic environs, Heliyon, 5
(2019) e02711. https://doi.org/10.1016/j.
heliyon.2019.e02711.
[12] M.T. Yagub, T.K. Sen, S. Afroze, H.M.
Ang, Dye and its removal from aqueous
solution by adsorption: a review, Adv. Coll.
Inter. Sci., 209 (2014) 172-184. https://doi.
org/10.1016/j.cis.2014.04.002.
[13] T.A. Saleh, Protocols for synthesis of
nanomaterials, polymers, and green
materials as adsorbents for water treatment
technologies, Environ. Tech. Innov., 24
Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
15
(2021) 101821. https://doi.org/10.1016/j.
eti.2021.101821.
[14] X. Liu, H. Pang, X. Liu, Q. Li, N. Zhang,
L. Mao, M. Qiu, B. Hu, H. Yang, X.
Wang, Orderly porous covalent organic
frameworks-based materials: superior
adsorbents for pollutants removal from
aqueous solutions, Innovation, 2 (2021)
100076. https://doi.org/10.1016/j.
xinn.2021.100076.
[15] I.C. Ossai, A. Ahmed, A. Hassan, F.S.
Hamid, Remediation of soil and water
contaminated with petroleum hydrocarbon:
A review, Environ. Tech. Innov., 17
(2020) 100526. https://doi.org/10.1016/j.
eti.2019.100526.
[16] J. Liu, G. Zhang, Recent advances in
synthesis and applications of clay-based
photocatalys ts: a review, Phys. Chem.
Chem. Phys., 16 (2014) 8178-8192. https://
doi.org/10.1039/C3CP54146K.
[17] Z. Wang, Z. Wang, S. Lin, H. Jin, S. Gao,
Y. Zhu, J. Jin, Nanoparticle-templated
nanofiltration membranes for ultrahigh
performance desalination, Nat. comm.,
9 (2018) 1-9. https://doi.org/10.1038/
s41467-018-04467-3.
[18] D. Yue, Y. Jing, J. Ma, C. Xia, X. Yin, Y.
Jia, Removal of neutral red from aqueous
solution by using modified hectorite,
Desalination, 267 (2011) 9-15. https://doi.
org/10.1016/j.desal.2010.08.038
[19] N.U.M. Nizam, M.M. Hanafiah, E.
Mahmoudi, A.A. Halim, A.W. Mohammad,
The removal of anionic and cationic dyes
from an aqueous solution using biomass-
based activated carbon, Sci. Rep., 11 (2021)
1-17. https://doi.org/10.1038/s41598-021-
88084-z
[20] C.F. Mok, Y.C. Ching, F. Muhamad, N.A.
Abu Osman, N.D.Hai, C.R. Che Hassan,
Adsorption of dyes using poly (vinyl
alcohol)(PVA) and PVA-based polymer
composite adsorbents: a review, J. Poly.
Environ., 28 (2020) 775-793. https://doi.
org/10.1007/s10924-020-01656-4
[21] I. Chaari, E. Fakhfakh, M. Medhioub, F.
Jamoussi, Comparative s tudy on adsorption
of cationic and anionic dyes by smectite
rich natural clays, J. Mol. S truct., 1179
(2019) 672-677. https://doi.org/10.1016/j.
mols truc.2018.11.039
[22] A.J. Ibrahim, ZnO nanos tructure synthesis
for the photocatalytic degradation of azo
dye methyl orange from aqueous solutions
utilizing activated carbon, Anal. Meth.
Environ. Chem. J., 5 (2022) 5-19. https://
doi.org/10.24200/amecj.v5.i04.200
[23] A.N.M.A. Haque, R. Remadevi, O.J.
Rojas, X. Wang, M. Naebe, Kinetics and
equilibrium adsorption of methylene
blue onto cotton gin trash bioadsorbents,
Cellulose, 27 (2020) 6485-6504. https://
doi.org/10.1007/s10570-020-03238-y
[24] A.J. Ibrahim, Ultraviolet-activated sodium
perborate process (UV/SPB) for removing
humic acid from water, Anal. Meth.
Environ. Chem. J., 5 (2022) 5-18. https://
doi.org/10.24200/amecj.v5.i03.191
[25] Y.M. Vargas-Rodríguez, A. Obaya, J.E.
García-Petronilo, G.I. Vargas-Rodríguez,
A. Gómez-Cortés, G. Tavizón, J.A.
Chávez-Carvayar, Adsorption s tudies of
aqueous solutions of methyl green for
halloysite nanotubes: Kinetics, isotherms,
and thermodynamic parameters, Amer.
J. Nanom., 9 (2021) 1-11. http://pubs.
sciepub.com/ajn/9/1/1
[26] J.A. Naser, T.A. Himdan, A.J. Ibraheim,
Adsorption kinetic of malachite green dye
from aqueous solutions by electrospun
nanofiber Mat, Orient. J. Chem., 33 (2017)
3121-3129. http://dx.doi.org/10.13005/
ojc/330654
[27] A.B. Fradj, A. Boubakri, A. Hafiane,
S.B. Hamouda, Removal of azoic dyes
from aqueous solutions by chitosan
enhanced ultrafiltration, Res. Chem., 2
(2020) 100017. https://doi.org/10.1016/j.
rechem.2019.100017
Adsorption of CV Dye by Cobalt-Hectorite Composite Ahmed Jaber Ibrahim
16
[28] C. Xia, Y. Jing, Y. Jia, D. Yue, J. Ma, X. Yin,
Adsorption properties of congo red from
aqueous solution on modified hectorite:
Kinetic and thermodynamic s tudies,
Desalination, 265 (2011) 81-87. https://
doi.org/10.1016/j.desal.2010.07.035
[29] B. Obradović, Guidelines for general
adsorption kinetics modeling, Hemi. Ind.,
74 (2020) 65-70. https://doi.org/10.2298/
HEMIND200201006O
[30] Y. Kuang, X. Zhang, S. Zhou, Adsorption
of methylene blue in water onto activated
carbon by surfactant modification, Water,
12 (2020) 587. https://doi.org/10.3390/
w12020587
[31] S. Debnath, U.C. Ghosh, Kinetics, isotherm
and thermodynamics for Cr(III) and
Cr(VI) adsorption from aqueous solutions
by crys talline hydrous titanium oxide, J.
Chem. Therm., 40 (2008) 67-77. https://
doi.org/10.1016/j.jct.2007.05.014
[32] A.S. Özcan, B. Erdem, A. Özcan,
Adsorption of Acid Blue 193 from
aqueous solutions onto Na–bentonite and
DTMA–bentonite, J. Coll. Inter. Sci., 280
(2004) 44-54 . https://doi.org/10.1016/j.
jcis.2004.07.035
Anal. Methods Environ. Chem. J. 6 (1) (2023) 5-16
