CC BY
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ISSN 2522-1841 (Online) ISSN 0005-2531 (Print)
UDC 541.73:547.458.81
SYNTHESIS OF ZnAl-LDH/PVA NANOCOMPOSITE AND ADSORPTION OF PATENT BLUE V FOOD DYE FROM WATER SOLUTION
O.O.Balayeva, A.A.Azizov, M.B.Muradov, R.M.Alosmanov, S.M.Zulfugarova,
M.H.Abbasov, S.J.Mammadyarova
Department of Chemistry, Baku State University
Received 09.09.2022 Accepted 21.10.2022
In the presented research work, zinc and aluminum containing layered double hydroxides on the polyvinyl alcohol matrix (ZnAl LDH/PVA) were prepared by the co-formation technique and characterized by X-ray diffractometer, Brunauer-Emmett-Teller (BET) and Ultraviolet-visible (UV-Vis) spectroscopy. Both low and high pH is determined as optimal pH for Patent Blue V (PBV) adsorption on the ZnAl LDH/PVA nanocomposite and it is explained by the fact that the dye molecule is zwitterionic. Sorption of Patent Blue V food additive (E 131) on the obtained nanocomposite was studied by Temkin, Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) isotherm models. Based on the obtained isotherm curves, the adsorption of PBV more closely matches Temkin model. The regenerated nanocomposite shows higher adsorption because the specific surface area increased from 5m2 g-1 to 8.94 m2 g-1 by BET analysis.
Keywords: layered double hydroxides (LDH), Patent Blue V (PBV), polyvinyl alcohol (PVA), nanocomposite, adsorption, optical properties.
doi.org/10.32737/0005-2531-2023-1-64-74
Introduction
Water quality control and its purification from hazardous pollutants are the most critical issues today. As technology and industry develop rapidly, the demand for new chemicals also increases [1]. Chemicals produced synthetically and used for various purposes release hazardous waste into nature during the production process or use. Since these wastes are stable in various conditions, they sometimes stay unchanged in soil and water for many years and cause various complications. Different methods like adsorption [2, 3], photodegradation [4, 5], separation [6, 7], bio-and chemical degradation [8, 9], coagulation [10, 11], filtration [12, 13], ultrasonication [14-16], etc. are implemented to fully ensure the purity of the water used for drinking or irrigation. These methods are different depending on the pollutant's nature, chemical and physical properties, molecular structure, and composition.
At present, the most demanded adsorbents and catalysts are chosen for multi-pollutants containing organic and inorganic contaminants and zwitterions. Zwitterions are both anionic and cati-onic molecules widely used in food technology,
drug delivery systems; chemical, bio-chemical and medicinal chemistry fields [17]. Another major cause of water pollution with organic matter is pharmaceuticals [18, 19]. PBV is zwitterionic dye is known by the food dye code E131 with chemical formula of C54H<32N4O14S4Ca. In some countries, PBV has been restricted as food coloring agent and it is not suggested for kids as it has been found to cause skin diseases, nausea and sometimes severe allergic symptoms [20-22] (Table 1).
Recently, LDHs have been investigated for their adsorption and photodegradation applications in catalysis due to their cationic lamellar structure, chemical and physical stability and reuseability [23-26]. The general formula of LDHs are described as [M2+n M3+ (OH)2 ]n+ [Az-]n/z x m H2O where, M2+ and M3+ are metal ions, Az- is interlayer anions maintains electro-neutrality in the crystal lattice of LDH.
High effective Visible-Light-Driven Co (or Cu)-doped ZnAl LDH photocatalysts were papered by coprecipitation method [27, 28].
The Co/Zn/Al (or Cu/Zn/Al) atomic proportions in beginning metal salts in mixed solution were set as 0/2/1; 0.1/2/1; 2/2/1 and 4/2/1 (0/2/1; 0.1/2/2; 1/2/1 and 2/2/1 for Cu).
Table 1. Chemical features of PBV dye compound [20-22]
Structure or Zwitterionic PBV dye (a) and Calcium-salt
nomenclature by IUPAC Calcium-4-[[4-(diethylamino)phenyl]-(4-diethylazaniumylidenecyclohexa-2,5-dien-1-ylidene)methyl] -6-hydroxybenzene - 1,3-disulfonate
Chemical formula C54H62CaN4Ü14S4
Molar weight 1159.4 gmol-1
E number 131
Xmax (nm) 640
It was found that Co (or Cu) doped LDH sheets demonstrate high absorption capacity for light than pure ZnAl/LDH materials. The authors explain this effectiveness by the Co (II) ions perform as photogenerated charges separator and it results in a higher photocatalytic degradation of RhB [27, 28].
Zn-Ti LDH/montmorillonite (ZTL/MT) and Fe-doped ZTL/MT (ZTL/Fe@MT 20%) have been synthesized by refluxing method as effective photocatalysts on the reduction of Cr(VI) ions [29]. The Fe-containing LDH/mont-morillonite composite prevents charge recombination and ensures the distribution of Cr(III) ions from the surface and/or MT interlayers. As a result, the overall photoelectrochemical equilibrium changes.
Mn-doped Zn/Al LDHs with Mn 0.5, 1, and 3 mol % with the respect to Zn content were studied [30]. In the photocatalytic degradation mechanism, it was found that Mn acts as an electron (Mn3+ and Mn4+) or as an hole trap (Mn2+ and Mn3+)
in accordance with its oxidation state and enhances the separation of charges.
Since Patent Blue V is an organic molecule of both cationic and anionic nature, choo-sing a unique adsorbent [31, 32] and catalyst [33-35] for its adsorption and photocatalytic degradation is not easy. A.Machrouhi et al. have been implemented the adsorption of PBV from aqueous solution by as-obtained and calcined Zn/Al-LDH [36]. They conceived that the results were correlated with the Langmuir model, sufficiently,
and the maximum adsorption capacity - Qmax of as-obtained and calcined LDH were determined as 185.4 and 344.37 mg/g. This increase in Qmax and KL of calcined LDH was explained by reconstruction phenomena [37]. The calcination process of LDHs leads to the carbonate anion CO3 2- decomposition and the formation of mixed metal oxides with a memory effect [36]. By hydration of LDH in the dye solution, they are reconstructed by the intercalation of dye molecules in LDH's interlayer space [37].
In the literature, there are very few works on the adsorption or photodegradation of PBV from water by LDHs. Here, an effective adsorption and photodegradation of PBV from aqueous solutions by ZnAl - LDH/PVA nanocomposite has been explained and investigation of experimental parameters was shown in detail. In the presented work, the high efficiency in the reuse of the adsorbent (photocatalyst) after sorption and photodegradation is explained by the structural and optical properties. Also, a series experiments were completed to investigate the effect of polymer in LDH nanocomposite on adsorption and pho-todegradative regeneration of the nanocomposite.
Experimental part
Reagent grade ZnSO47H2O, Al2(SO4)3l8H2O, NaOH, urea and PVA were used in the experiment for the obtain of adsorbent and photocatalyst, unsafe dye Patent Blue V (PBV) was used as pollutant.
Zn and Al containing LDH nanocom-posite within PVA matrix was obtained by the
chemical co-formation method. The final pH of the obtained slurry was adjusted 9. The 10% of 40 ml PVA/water solution has been used before adding the base solution. The molar ratio of Zn/Al was taken as (3/1). The obtained slurry was aged at room temperature for 24h and heated at ~900C. The obtained samples washed with distilled hot water (900C), dried at the ambient condition and room temperature, shredded into little parts and used on the adsorption of PBV.
Zn and Al containing LDH obtained with the presence of PVA in pure (as obtained) and after the adsorption and photodegradation were characterized by X-ray diffractometer (XRD) with the radiation of CuKa (k = 0.154 nm) by Bruker D8, and ultraviolet spectroscopy (UV-Vis) using Specord 210+.
The adsorption properties of the obtained sample have been tested for PBV. The optimal pH of adsorption was determined and the concentrations of dye molecules in the solutions were measured by UV-Vis spectroscopy at 631.5 nm maximum absorbance wavelength. The adsorption efficiency (1) has been determined by the eq. 1.
Co
%R =
"Ce
x 100
C — (1) C0
Co is an initial concentration
is an equilibrium concentration
Where (mg/L), Ce (mg/L) of dye compound into distilled water.
0,7
0,6
0,5
Ml
E 0,4
0,3
+J
<u (J 0,2
o
u 0,1
0
y = 0,0821x R2 = 0,9961
0
-r-
4
Absorbance at 631,5 nm
Fig. 1. Calibration curve for Patent Blue V.
The calibration curve (Figure 1) was created for PBV and based on the obtained equa-
tion (y=0.082x), the concentrations of dye solutions were calculated.
The PBV adsorption with Zn and Al containing LDH/PVA was put into the experiment with various initial concentrations and studied by Langmuir with Eq. (2) and (3) [38], Freundlich with Eq. (4) [39], Temkin with Eq. (5) [40] and Dubinin-Radushkevich (D-R) with Eq. (6), (7) and (8) [41] isotherm models:
i
qe Qmax^KL
+ '
qmax
R=
1
(1+Kl-CO)
1
logqe = logKF + -logc,
n
RT RT
qe = ^lnAT +— lnce
Ut DT
lnqe = lnqr
ßs2
s = RTln(1 + -)
c
E =
1
T2ß
(2)
(3)
(4)
(5)
(6)
(7)
(8)
Where, qe is an equilibrium adsorption capacity (mg/g); qmax - is the maximum adsorption capacity (mg/g); KL and KF are Langmuir and Freundlich constants; bT and P are Temkin and (D-R) constants; s and n are Polany potential and adsorption intensity; AT is the equilibrium binding constant of Temkin isotherm (L/g).
Results and discussion
The synthesized ZnAl-LDH/PVA nano-composites was used for the PBV adsorption. The impact of the pH on adsorption of PBV with the synthesized ZnAl-LDH/PVA nano-composite shows that the sample is a best adsorbent at pH2 and pH8 (Figure 2).
c
c
e
e
e
100 — 90
J 80
a
o 70
to
lo 60 ^ 50 40 30
0 12 3
4 5 pH
6 7 8 9 10
Fig. 2. Influence of the pH on adsorption of PBV onto ZnAl - LDH/PVA.
The optimal adsorption of the nanocom-posite both at low and high pH is explained by the fact that the PBV dye molecule is zwitte-rionic.
The normalized isothermal models for PBV onto ZnAl-LDH/PVA nanocomposite was presented at Figure 3. As seen from the results, the adsorption mostly fits the Temkin isotherm model. However, Langmuir and Freundlich models can also be determined as optimal models for the sorption of PBV onto obtained nano-composite because of the high correlation coefficient.
1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0
0
Langmuir model
y = 0,0643x + 0,506 R2 = 0,9347
10
ce (mg/L)
15
20
g g/
3 2,5 2 1,5 1 0,5
0
-0,5
0
Freundlich model
y = 0,6545x + 0,5927 R2 = 0,9702
123 ln ce (mg/L)
4
5
Fig. 3. Adsorption isotherms of the
onto ZnAl LDH/PVA nanocomposite.
According to Langmuir isotherm model the homogeneity of active centers on the surface once again proves the dispersed distribution of LDH in the polymer. Since active centers on a homogeneous surface have the same adsorption energy, the adsorption of zwitterionic molecules increases due to electrostatic forces. The separation factor (Rl) (Eq.9) indicating the possibility of adsorption gets values lower than 1 at all concentrations, and it approaches to 0 with an increase in the initial concentration of the dye in the solution. This indicates that ZnAlLDH/PVA is a proper adsorbent for the sorption of PBV dye [42, 43].
Rt
1
1+KLXCo
(9)
Compared to obtained results by Langmuir isotherm model, the Freundlich model is more suitable on the adsorption PBV with ZnAlLDH/PVA. This shows that although the active centers are homogeneously distributed over the surface as given above, heterogeneous distribution prevails. Since the synthesis of the nanocomposite takes place in a polymer solution, a heterogeneous distribution of functional surface centers is expected, and this situation further activates the sorption of zwitterions. Therefore, sorption can be explained approximately equally by both Langmuir and Freundlich models. With that said, the 1/n slope value close to one (1/n= 0.654), which suggests the probability of the adsorption according to Freundlich isotherm [44, 45].
Based on the isotherm curves, we can say that the adsorption more closely matches the Temkin model and we can more accurately explain the energy of sorption according to Tem-kin's model. So, although according to the D-R model and sorption has a physical nature (E=1.56 kJ/mol), according to the Temkin model, sorption has both a physical and chemical
nature (E=8.04 kJ/mol) with indirect interaction between adsorbent and adsorbate. This character is dominated by the isotherm constants, so, Temkin constant (bT=8.04 kJ/mol) is higher than the D-R constant (P=0.205) (Table 2).
The regeneration of nanocomposite is carried out by sunlight irradiation. In the regeneration experiment the solution on the top of the nanocomposite released and same amount of water added to the PBV loaded nanocomposite and irradiated under sunlight during July 2022, from 11:00 AM to 03:00 PM, at Baku, Azerbaijan. During 4h, the ZnAl LDH/PVA nanocom-posite returned to its original color. The regenerated nanocomposite show higher adsorption because the specific surface are increased from 5m2 g-1 to 8.94 m2 g-1 by BET analysis. The high adsorption activity is explained by structural and optical properties.
XRD patterns of ZnAl-LDH/PVA is presented at Figure 4. According to literature, the shift of diffraction peak to the right occurs by transverse bonds formation in PVA and crystal lattice compression [46-48]. The characteristic diffraction peak of PVA at 20 =19.170 diffraction angle [49] shift to 20=2O0 upon the formation of LDH is related by the cross-linking of PVA by ZnAl - LDH [48]. The XRD diffracto-grams of pure ZnAl - LDH/PVA nanocompo-site demonstrates the characteristic reflections corresponding to ZnAl - LDH crystal phase (JCPDS code No. 48 - 1023) [50] and indexed {003}; {006}; {101}; {015}; {018}; {110} and {113} planes.
As can be seen, the appeared doubling of the XRD peaks is demonstrated by strained (sharp) and relaxed (broad) phases [50]. Souza S.C. et al. clarify with second crystal structure formation cause [51]. With a clearer appearance of the doubling (splitting) of the diffraction peaks after the dye adsorption, we can easily say that there is a second crystalline phase.
Table 2. The obtained parameters from isotherms for the adsorption of patent blue V on the ZnAl-LDH nanocomposite obtained in PVA matrix
Langmuir Freundlich D-R Temkin
Qmax (mg/g) KL (L/mg) R2 KF (L/mg) 1/n R2 ß E (kJ/mol) Qmax (mg/g) R2 bT (kJ/mol) Kt (L/mg) R2
15.625 0.126 0.934 1.808 0.645 0.970 0.205 1.562 6.24 0.684 8.04 0.333 0.993
2 Theta 1 degree Fig. 4. XRD diffractogram of ZnAl-LDH/PVA nanocomposite.
s-Zn (OH)2 was formed as a second crystalline phase together with LDH. In addition to it, the reason for the formation of another phase of Zn(OH)2 like a- and P- phases are the participation of the polymer in the formation stage of the LDH [52-54]. Here it could also be happen by the formation of LDH with different inter-layer distances because of the polymer. According to the above idea, an analogy was observed in the average size of the nanoparticles after PBV adsorption and photodegradation. Thus, if the size of as-obtained ZnAl LDH nanoparticles was 17 nm (this is an estimate from the intensive peak), the crystallite size of LDH increased by the adsorption and decreased with photodegradation. On the other hand, with the entering of large PBV zwitterionic into the nanocomposite and by the expansion of LDH interlayer space, the aggregation of s-Zn(OH)2 nanoparticles occurred with 25nm particle size in adsorption process. However, with the photodegradation of PBV, the LDH interlayer distance partially returned to its previous state (memory effect), resulting in voids in the nanocomposite interspace. At this time, the agglomerated s-Zn(OH)2 nanoparticles separated from the agglomerates (disintegrated) in that space and were dispersed, particle size decreased (24.63 nm^-18.55 nm). After the adsorption of PBV dye in the nanocomposite, the average size of the polymer (PVA) also increased (4.03 nm^-4.21 nm). This is explained by absorption of dye into LDHs and the stretching of the pol-
ymer chain. With subsequent photodegradation of PBV, the reduction of the average size of the polymer particles (4.21 nm^-3.37 nm) can occur with the partial destruction of the polymer chain under the influence of sunlight.
Table 3. Crystal structure parameters of ZnAl-LDH/PVA nanocomposite determined by XRD results_
Parameters As-synthesized ZnAl -LDH/PVA [52]
Basal spacing (A) d (003) 7.00
d (006) 3.64
d(110) 1.52
a = 2 x d(n0) 3.04
c = 3 x d(003) 21.00
D(003) (particle size) (nm) 17.11
D(006) (particle size) (nm) 13.26
PVA (particle size) (nm) 4.03
Interlayer distance (A) 2.2
The optical characterization and band gap (Eg) energy of the ZnAl-LDH/PVA nano-materials as-obtained, PBV dye loaded and after the photodegradation of PBV were studied by UV-Vis spectroscopy (Figure 5).
The band gap energy of nanomaterials were estimated by using Tauc's equation (Eq. 10) [55] (ahv)n = tf(hv - Eg) (10)
where, a-Absorption coefficient = 2.303A, h is
OA J
Plank' s constant = 6.626 x 10- m kg/s; v is frequency (Hz); K-is an energy constant, Eg-optical band gap (eV) and n is nature of transmission =2(for direct) or 1/2 (for indirect tansi-tion) [55, 56].
ZnAI LDH/PVA
— After dye sorption
— After photodegradation of dye Fig. 5. Optical bandgap curves of ZnAlLDH/PVA nanomaterials as obtained, after PBV adsorption and photodegradation.
Table 4. Optical bandgap values of ZnAlLDH/PVA nanomaterials as obtained, after PBV adsorption and photodegradation
ZnAl LDH/PVA Egi (eV) Eg2 (eV) Eg3 (eV)
As-obtained 5.8 3.25 3.2
After PBV sorption - 2.9 2.7
After sunlight degradation - 2.55 3.12
Because LDH contains different metal atoms and inorganic anions, they demonstrate three bandgap energies like Eg1 (high), Eg2 (middle) and Eg3 (low ) phase [23, 57, 58]. The (Eg1) shows the high energy gap and could be elucidated the presence of NO3- ions existing in LDH interlayers [52, 59]. It is shown in Figure 3 that, only the as obtained LDH/PVA nano-composite has a band gap of Eg1 and it is equal to 5.8 eV. The nanocomposites measured after the adsorption and photodegradation of PBV have not got high bandgap energy because the intercalation of dye molecules after the sorption and water molecules after the photodegradation under sunlight. The values of Eg2 of ZnAl-LDH/PVA nanocomposites as obtained, PBV dye adsorbed and after photodegradation equal to 3.25, 2.9 and 2.55 eV , respectively. The decrease of the Eg2 band gap energy as shown makes the obtained nanocomposite more potential for reuse in catalytic applications. The values of Eg3 of ZnAl-LDH/PVA nanocomposites as obtained, PBV dye adsorbed and after photodegradation equal to 3.2, 2.7 and 3.12 eV , respectively. As can be seen, the increase in the band gap energy (Eg3) of the nanocomposite after the adsorption is the result of intercalation, and the catalyst partially returns to its previous state due to the memory effect after photodegradation.
Conclusion
In the presented work, ZnAl-LDH nano-particle were synthesized into PVA matrix and the effective adsorption of Patent Blue V from aqueous solutions was studied in detail. The high efficiency in the reuse of the adsorbent after the sorption was clarified by the structural and optical properties of nanocomposite. The optimal adsorption of the nanocomposite both at low and high pH is explained by the fact that the PBV dye molecule is a zwitterion. It was found that, since active centers on a homogeneous surface have the same adsorption energy, the adsorption of zwitter-ionic molecules increases due to electrostatic forces. Although according to the D-R model the sorption has a physical nature (E=1.56 kJ/mol), according to the Temkin model, it has both a physical and chemical nature (E=8.04 kJ/mol)
with indirect interaction between adsorbent and adsorbate. Because the Temkin constant (bT=8.04 kJ/mol) is higher than the D-R constant (P=0.205), the sorption energy is accurately explained according to Temkin's model. The regeneration of nanocomposite is carried out by photodegradation of dye molecules from the nanocom-posite by sunlight irradiation.
Acknowledgments
Author thanks the High Molecular Compounds Chemistry sub-department at Baku State University for the facilities in laboratory. Author thanks Dr. Mammadyarova Sevinj and Nano- Research laboratory, at Baku State University for XRD characterizations and Dr. Zulfugarova Sima from Institute of Catalysis and Inorganic Chemistry, Azerbaijan National Academy of Sciences, for BET analysis.
References
1. Rauf M.A., Ashraf S.S. Fundamental principles and application of heterogeneous photocatalytic degradation of dyes in solution. Chem. Eng. J. 2009. V. 151. P. 10-18. doi:10.1016/j.cej. 2009.02.026.
2. Mahmoud R.K., Taha M., Zaher A., Amin R.M. Understanding the physicochemical properties of Zn-Fe LDH nanostructure as sorbent material for removing of anionic and cationic dyes mixture. Sci. Rep. 2021. V. 11. doi:10.1038/s41598-021-00437-w.
3. Ali B., Naceur B., Abdelkader E., Karima E., Nourredine B. Competitive adsorption of binary dye from aqueous solutions using calcined layered double hydroxides. Int. J. Environ. Anal. Chem. 2020. doi:10.1080/03067319.2020.1766035.
4. Mahjoubi F.Z., Khalidi A., Abdennouri M., Barka N., Zn-Al layered double hydroxides intercalated with carbonate, nitrate, chloride and sulphate ions: Synthesis, characterisation and dye removal properties. J. Taibah Univ. Sci. 2017. V. 11. P. 90-100. doi:10.1016/jjtusci.2015.10.007.
5. Aissani A., Kameche M., Benabbou K., Synthesis and characterization of TiO2/LDH layered double hydroxide composites: Utilization as photocatalysts for amoxicillin degradation under uVa irradiation. Inorg. Nano-Metal Chem. 2022. doi:10.1080/ 24701556.2022.2068582.
6. Sacara A.M., Indolean C., Cristea V.M., Mure§an L.M., Application of adaptive neuro-fuzzy interference system on biosorption of malachite green using fir (Abies nordmanniana) cones biomass. Chem. Eng. Commun. 2019. V. 206. P. 12491263. doi:10.1080/00986445.2018.1555531.
7. Paprowicz J.T. Activated carbons for phenols removal from wastewaters. Environ. Technol. (Unit-
ed Kingdom). 1990. V. 11. P. 71-82. doi: 10.1080/09593339009384840.
8. Li C., Yu S., Gu L., Han J., Dong H., Wang Y., Chen G. A new graphitic carbon nitride/horseradish peroxidase hybrid nano-bio artificial catalytic system for unselective degradation of persistent phenolic pollutants. Adv. Mater. Interfaces. 2018. V. 5. doi:10.1002/admi.201801297.
9. Fernández de Dios M.Á., Rosales E., Fernández-Fernández M., Pazos M., Sanromán M.Á. Degradation of organic pollutants by heterogeneous electro-Fenton process using Mn-alginate composite. J. Chem. Technol. Biotechnol. 2015. V. 90. P. 1439-1447. doi:10.1002/jctb.4446.
10. Ding A., Ren Z, Hu L., Zhang R., Ngo H.H., Lv D., Nan J., Li G., Ma J. Oxidation and coagulation/adsorption dual effects of ferrate (VI) pre-treatment on organics removal and membrane fouling alleviation in UF process during secondary effluent treatment. Science of The Total Environment. 2022. V. 850. P. 157986. doi.org/ 10.1016 /j.scitotenv.2022.157986
11. Lin R., Li Y., Yong T., Cao W., Wu J., Shen Y. Syn-ergistic effects of oxidation, coagulation and adsorption in the integrated fenton-based process for wastewater treatment: A review. J. Environ. Manage. 2022. V. 306. doi:10.1016/j.jenvman. 2022.114460.
12. Madaeni S.S., Heidary F., Salehi E. Co-adsorption/filtration of heavy metal ions from water using regenerated cellulose UF membranes modified with DETA ligand Sep. Sci. Technol. 2013. V. 48. P. 1308-1314. doi:10.1080/ 01496395. 2012.735741.
13. Kus B., Johir M., Kandasamy J., Vigneswaran S., Shon H.Y., Sleigh R., Moody G. Performance of granular medium filtration and membrane filtration in treating storm water for harvesting and reuse. Desalin. Water Treat. 2012. V. 45. P. 120127. doi:10.1080/19443994.2012.692018.
14. Bisaria K., Sinha S., Iqbal H.M.N., Singh R. Ul-trasonication expedited As(III) adsorption onto chitosan impregnated Ni-Fe layered double hydroxide biosorbent: Optimization studies and artificial intelligence modeling. Environ. Res. 2022. V. 212. doi:10.1016/j.envres.2022.113184.
15. Cali§kan B., §ayan E. A brief overview of the effects of ultrasound on the adsorption/desorption process: a review. Intern. J. Environ. Anal. Chem. 2022. doi: 10.1080/03067319.2022.2093641
16. Saharan P., Kumar V, Mittal J., Sharma V., Shar-ma A.K. Efficient ultrasonic assisted adsorption of organic pollutants employing bimetallic-carbon nanocomposites. Sep.Sci. Technol. 2021. V. 56. P. 2895-2908. doi:10.1080/01496395.2020.1866608.
17. Yang Z., Li Q., Yang G. Zwitterionic structures: From physicochemical properties toward computer-aided drug designs. Future Med. Chem. 2016. V. 8. P. 2245-2262. doi:10.4155/fmc-2016-0176.
18. Ogunbanwo O.M., Kay P., Boxall A.B., Wilkinson J., Sinclair C.J., Shabi R.A., Fasasi A.E., Lewis G.A., Amoda O.A., Brown L.E. High Con-
centrations of Pharmaceuticals in a Nigerian River Catchment. Environ. Toxicol. Chem. 2022. V. 41. P. 551-558. doi:10.1002/etc.4879.
19. Lin A.Y.C., Reinhard M. Photodegradation of common environmental pharmaceuticals and estrogens in river water. Environ. Toxicol. Chem. 2005. V. 24. P. 1303-1309. doi:10.1897/04-236R.1.
20. Gessner T. Triarylmethane and Diarylmethane Dyes. Ullmanns Encycl. Ind. Chem. 2012. V. 37. P. 425-474. DOI: 10.1002/14356007. a27_179.
21. Barthelmes L., Goyal A., Newcombe R.G., McNeill F., Mansel R.E. Adverse reactions to patent blue V dye - The NEW START and ALMANAC experience. Eur. J. Surg. Oncol. 2010. V. 36. P. 399-403. doi:10.1016/j.ejso. 2009. 10.0 Sabnis R. W. "Patent Blue V". Handbook of Acid-Base Indicators. CRC Press. 2008. P. 295297. ISBN 9780849382185
22. Balayeva O.O., Azizov A.A., Muradov M.B., Alosmanov R.M., Eyvazova G.M., Mammadyarova S.J. Cobalt chromium-layered double hydroxide, a-and ß- Co(OH)2 and amorphous Cr(OH)3: synthesis, modification and characterization. Heliyon. 2019. V. 5. doi:10.1016/j.heliyon.2019.e02725.
23. Bouarroudj T., Aoudjit L., Djahida L., Zaidi B., Ouraghi M., Zioui D., Mahidine S., Shekhar C., Bachari K. Photodegradation of tartrazine dye favored by natural sunlight on pure and (Ce, Ag) co-doped ZnO catalysts. Water Sci. Technol. 2021. V. 83. P. 2118-2134. doi:10.2166/wst.2021.106.
24. Pahalagedara M.N., Samaraweera M., Dharmara-thna S., Kuo C.H., Pahalagedara L.R., Gascón J.A., Suib S.L. Removal of azo dyes: Intercalation into sonochemically synthesized NiAl layered double hydroxide. J. Phys. Chem. C. 2014. V. 118. P. 17801-17809. doi: 10.1021/jp505260a.
25. Seftel E.M., Niarchos M., Vordos N., Nolan J.W., Mertens M., Mitropoulos A.C., Vansant E.F., Cool P. LDH and TiO2/LDH-type nanocomposite systems: A systematic study on structural characteristics. Micropor. Mesopor. Mater. 2015. V. 203. P. 208-215. doi:10.1016/j.micromeso.2014.10.029.
26. Li D., Fan L., Qi M., Shen Y., Liu D., Li S. Enhanced visible-light-driven photocatalytic activity of ZnAl layered double hydroxide by incorporation of Co2+. Bull. Chem. React. Eng. &Amp; Catal. 2018. V. 13. P. 502-511. doi:10.9767/bcrec. 13.3. 2168.502-511.
27. Li D., Fan L., Shen Y., Qi M., Ali M.R., Liu D., Li S. Degradation of Rhodamine B Under Visible-Light by Cu-Doped ZnAl Layered Double Hydroxide. J. Nanosci. Nanotechnol. 2018. V. 19. P. 1090-1097. doi:10.1166/jnn.2019.15741.
28. Chuaicham C., Xiong Y., Sekar K., Chen W., Zhang L., Ohtani B., Dabo I., Sasaki K. A promising Zn-Ti layered double hydroxide/Fe-bearing montmorillonite composite as an efficient photocatalyst for Cr(VI) reduction: Insight into the role of Fe impurity in mont-morillonite. Appl. Surf. Sci. 2021. V. 546. doi: 10.1016/j .apsusc.2020.148835.
29. Morales-Mendoza G., Tzompantzi F., García-Mendoza C., López R., De la Luz V., Lee S.W., Kim T.H., Torres-Martínez L.M., Gómez R. Mn-doped Zn/Al layered double hydroxides as photo-catalysts for the 4-chlorophenol photodegradation. Appl. Clay Sci. 2015. V. 118. P. 38-47. doi:10.1016/j.clay.2015.08.030.
30. Giri B.S., Goswami M., Kumar P., Yadav R., Sharma N., Sonwani R.K., Yadav S., Singh R.P., Rene E.R., Chaturvedi P., Singh R.S. Adsorption of patent blue V from textile industry wastewater using sterculia alata fruit shell biochar: Evaluation of efficiency and mechanisms. Water (Switzerland). 2020. V. 12. doi:10.3390/w12072017.
31. Roy K., Verma K.M., Vikrant K., Goswami M., Sonwani R.K., Rai B.N., Vellingiri K., Kim K.H., Giri B.S., Singh R.S., Removal of patent blue (V) Dye using indian bael shell biochar: Characterization application and kinetic studies. Sustain. 2018. V. 10. doi:10.3390/su10082669.
32. Barka N., Qourzal S., Assabbane A., Nounah A., Ait-Ichou Y. Photocatalytic degradation of patent blue V by supported TiO2: Kinetics, mineralization, and reaction pathway. Chem. Eng. Commun. 2011. V. 198. P. 1233-1243. doi:10.1080/ 00986445.2010.525206.
33. Vaiano V., Iervolino G., Sannino D., Murcia J.J., Hidalgo M.C., Ciambelli P., Navío J.A. Photocatalytic removal of patent blue V dye on Au-TiO2 and Pt-TiO2 catalysts. Appl. Catal. B Environ. 2016. V. 188. P. 134-146. doi:10.1016/j. apcatb. 2016.02.001.
34. Sadiq M., Elhalil A., Abdennouri M., Barka N., Bensitel M., Lamonier C. Effect of aluminium incorporation on physicochemical properties and patent blue V photodegradation of magnesium phosphate materials. Bull. Mater. Sci. 2021. V. 44. doi: 10.1007/s12034-020-02312-2.
35. Machrouhi A., Taoufik N., Elhalil A., Tounsadi H., Rais Z., Barka N. Patent Blue V Dye Adsorption by Fresh and Calcined Zn/Al LDH: Effect of Process Parameters and Experimental Design Optimization. J. Compos. Sci. 2022. V. 6. doi: 10.3390/jcs6040115.
36. Mascolo G., Mascolo M.C. On the synthesis of layered double hydroxides (LDHs) by reconstruction method based on the "memory effect". Microporous Mesoporous Mater. 2015. V. 214. P. 246-248. doi:10.1016/j.micromeso.2015.03.024.
37. Langmuir I. The constitution and fundamental properties of solids and liquids. J. Franklin Inst. 1917. V. 183. P. 102-105. doi:10.1016/S0016-0032(17)90938-X.
38. Freundlich H.M.F. Over the adsorption in solution., J. Phys. Chem. 1906. V. 57. P. 1100-1107.
39. Tempkin M. J., Pyzhev V. Kinetics of ammonia synthesis on promoted iron catalyst, Acta Phys. Chim. USSR. 1940. V. 12. 327.
40. Dubinin M.M. The potential theory of adsorption of gases and vapors for adsorbents with energeti-
cally nonuniform surfaces. Chem. Rev. 1960. V. 60. 235-241. doi:10.1021/cr60204a006.
41. Hall K.R., Eagleton L.C., Acrivos A., Vermeulen T. Pore- and solid-diffusion kinetics in fixed-bed adsorption under constant-pattern conditions. Ind. Eng. Chem. Fundam. 1966. V. 5. P. 212-223. doi:10.1021/i160018a011.
42. Balayeva O.O., Azizov A.A., Muradov M.B., Alos-manov R.M., Mursalova G.Q., Rahimli K.S., Agha-maliyev Z.A. Synthesis of zinc-aluminum mixed oxide/polyvinyl alcohol (ZnAl mixed oxide/PVA) and application in Pb(II) removal from aqueous solution. J. Dispers. Sci. Technol. 2021. V. 42. P. 1482-1493. doi:10.1080/01932691.2020.1773848.
43. Balayeva O.O., Azizov A.A., Muradov M.B., Alosmanov R.M. Removal of tartrazine, ponceau 4R and patent blue V hazardous food dyes from aqueous solutions with ZnAl-LDH/PVA nanocomposite. J. Dispers. Sci. Technol. 2021. doi:10.1080/01932691.2021.2006688.
44. Gong R., Zhang X., Liu H., Sun Y., Liu B. Uptake of cationic dyes from aqueous solution by biosorption onto granular kohlrabi peel. Bioresour. Tech-nol. 2007. V. 98. P. 1319-1323. doi:10.1016/ j.biortech.2006.04.034.
45. Sonker A.K., Rathore K., Nagarale R.K., Verma V. Crosslinking of Polyvinyl Alcohol (PVA) and Effect of Crosslinker Shape (Aliphatic and Aromatic) Thereof. J. Polym. Environ. 2018. V. 26. P. 1782-1794. doi: 10.1007/s10924-017-1077-3.
46. Gahramanli L.R., Muradov M.B., Balayeva O.O., Eyvazova G.M., Mirsultanova R.M. Role of temperature in the growth and formation of CdxZn1-xS/PVA nanocomposites through SILAR method. Mater. Res. Bull. 2021. V. 137. doi:10.1016/j. ma-terresbull.2020.111162.
47. Balayeva O.O. Photocatalytic degradation of Ponceau 4R by ZnAl-layered double hydroxide nano-structures obtained with and without polyvinyl alcohol. J. Chinese Chemical Society (JCCS). 2022. https://doi.org/10.1002/jccs.202200121
48. Gupta S., Pramanik A.K., Kailath A., Mishra T., Guha A., Nayar S., Sinha A. Composition dependent structural modulations in transparent poly(vinyl alcohol) hydrogels. Colloids Surfaces B Biointerfaces. 2009. V. 74. P. 186-190. doi:10.1016/j.colsurfb.2009.07.015.
49. Kappertz O., Drese R., Wuttig M. Correlation between structure, stress and deposition parameters in direct current sputtered zinc oxide films. J. Vac. Sci. Technol. A Vacuum, Surfaces, Film. 2002. V. 20. 2084. doi:10.1116/1.1517997.
50. De Souza S.C., Alves M.C.F., De Oliveira A.L.M., Longo E., Ticiano Gomes Vieira F., Gomes R.M., Soledade L.E.B., De Souza A.G., Garcia Dos Santos I.M., SrSnO3:Nd obtained by the polymeric precursor method. J. Therm. Anal. Calorim. 2009. V. 97. P. 185-190. doi: 10.1007/ s10973-009-0239-5.
51. Balayeva O.O. Synthesis and characterization of zinc-aluminum based layered double hydroxide
and oxide nanomaterials by performing different experimental parameters. J. Dispers. Sci. Technol. 2022. V. 43. P. 1187-1196. doi:10.1080/ 01932691.2020.1848580.
52. Wang M., Jiang L., Kim E.J., Hahn S.H. Electronic structure and optical properties of Zn(OH)2: LDA+U calculations and intense yellow luminescence. RSC Adv. 2015. V. 5. P. 87496-87503. doi:10.1039/c5ra17024a.
53. Mousavi-Kamazani M., Zinatloo-Ajabshir S., Ghodrati M. One-step sonochemical synthesis of Zn(OH)2/ZnV3O8 nanostructures as a potent material in electrochemical hydrogen storage. J. Mater. Sci. Mater. Electron. 2020. V. 31. P. 1733217338. doi:10.1007/s10854-020-04289-4.
54. Tauc J., Grigorovici R., Vancu A. Optical properties and electronic structure of amorphous germanium. Phys. Status Solidi. 1966. V. 15. P. 627637. doi:10.1002/pssb.19660150224.
55. Balayeva O.O., Azizov A.A., Muradov M.B., Ma-harramov A.M., Eyvazova G.M., Alosmanov R.M., Aghamaliyev Z.A. Synthesis and study of
copper sulfide (Cu18S) nanocrystals on the basis of phosphorus containing polymer sorbent (PCPS) by chemical route. Azerb. Chem. Journ. 2015. V. 2. P. 71-76.
56. Naseem S., Gevers B.R., Labuschagne F.J.W.J., Leuteritz A. Preparation of photoactive transition-metal layered double hydroxides (LDH) to replace dye-sensitized materials in solar cells. Materials (Basel). 2020. V. 13. P. 1-12. doi: 10.3390 /ma13194384.
57. Chowdhury P.R., Verma V., Medhi H., Bhat-tacharyya K.G. Mn/Ti layered double hydroxide: An investigation into the structure and electron transport through combinatorial experimental and theoretical approaches. Mater. Res. Express. 2019. V. 6 .doi:10.1088/2053-1591/ab6a49.
58. Ahmed A.A.A., Talib Z.A., Bin Hussein M.Z., Zakaria A. Zn-Al layered double hydroxide prepared at different molar ratios: Preparation, characterization, optical and dielectric properties. J. Solid State Chem. 2012. V. 191. P. 271-278. doi:10.1016/j.jssc.2012.03.013.
ZnAl-LDH/PVA NANOKOMPOZITININ SINTEZI УЭ PATENT MAVISI V QIDA BOYASININ SULU
MOHLULLARDAN ADSORBSiYASI
O.O.Balayeva, A.e.Ozizov, M.B.Muradov, R.M. Alosmanov, S.M.Zülfüqarova, M.H.Abbasov,
S.C.Mammadyarova
Taqdim olunan tadqiqat i§inda sink va alüminium tarkibli layli ikili hidroksidlar (ZnAl - LiH) polivinil spirti (PVS) matrisinda birga formala§dirma metodu ila sintez edilmi§ va alinmi§ nanomateriallar Rentgen difraktometri, Brunauer-Emmett-Teller (BET) va ultrabanöv§ayi spektroskopiya ila tadqiq edilmi§dir. Ham yüksak, ham da a§agi pH patent mavisinin ZnAl LiH/PVS -da sorbsiyasi ügün optimal pH segilmi§dir va bunun sababi boyaq molekulunun zvitterion olmasi ila izah edilmi§dir. Alinmi§ nanokompozitda Patent Blue V qida alavasinin (E 131) sorbsiyasi Temkin, Freundlich, Langmuir va Dubinin-Radushkevich (D-R) izoterm modellari ila tadqiq edilmi§dir. Alinan izoterm ayrilarina asasan, PBV-nin adsorbsiyasi Temkin modelina daha gox uygun galir. BET analizi ila xüsusi sath sahasi 5m2 g-1-dan 8.94 m2 g-1-a kimi yüksaldiyi ügün barpa olunan nanokompozit daha yüksak adsorbsiya göstarmi§dir.
Agar sözlzr: layli ikili hidroksidlar (LiH), Patent mavisi V, polivinil spirti (PVS), nanokompozit, adsorbsiya, optik xassabr.
СИНТЕЗ НАНОКОМПОЗИТА ZnAl-СДГ/ПВС И АДСОРБЦИЯ ИЗ ВОДНОГО РАСТВОРА ПИЩЕВОГО КРАСИТЕЛЯ СИНИЙ ПАТЕНТОВАННЫЙ V
О.О.Балаева, А.А.Азизов, М.Б.Мурадов, Р.М.Алосманов, С.М.Зульфугарова, М.Г.Аббасов,
С.Дж.Маммадьярова
В представленной исследовательской работе цинк- и алюминийсодержащие слоистые двойные гидроксиды на матрице поливинилового спирта ZnAl-СДГ/ПВС были получены методом соформирования и иследованы с помощью Рентгеновского дифрактометра, Брунауэра-Эммета-Теллера (БЭТ) и ультрафиолетовой спектроскопии. Как низкое, так и высокое значение pH является как оптимальное значение pH для адсорбции Синий патентованный V (СП-V) на нанокомпозите ZnAl-СДГ/ПВС и объясняется тем, что молекула красителя является цвиттерионной. Сорбцию пищевой добавки СП-V (E 131) на полученном нанокомпозите изучали по моделям изотерм Темкина, Фрейндлиха, Ленгмюра и Дубинина-Радушкевича (Д-Р). Судя по полученным изотермам, адсорбция СП-V более точно соответствует модели Темкина. Регенерированный нанокомпозит демонстрирует более высокую адсорбцию, так как удельная площадь поверхности увеличилась с 5 м2 г-1 до 8,94
м
г-1 по анализу БЭТ.
Ключевые слова: двойные слоистые гидроксиды (СДГ), Синий патентованный V(СП-V), поливиниловый спирт (ПВС), нанокомпозит, адсорбция, оптические свойства.
