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Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles
Author's Accepted Manuscript
Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani
www.elsevier.com/locate/matlet
PII: DOI: Reference:
S0167-577X(14)00134-7 http://dx.doi.org/10.1016/j.matlet.2014.01.118 MLBLUE16372
To appear in:
Materials Letters
Received date: 16 November 2013 Accepted date: 21 January 2014 Cite this article as: Iraj Kazeminezhad, Azar Sadollahkhani, Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles, Materials Letters, http://dx.doi.org/10.1016/j.matlet.2014.01.118 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz, Iran *
Corresponding author:
Email: [email protected], [email protected] Telefax: +98(611)3331040
Abstract In this study, ZnO nanoparticles were synthesized by co-precipitation method. The particles were used for degradation of Eriochrome black-T dye by examination at three different pH values. It was observed that the adsorption of dye onto ZnO nanoparticles surface is strongly dependent on the pH of the solution which plays an important role in photocatalytic degradation. Decomposition of Eriochrome black-T dye at pH 11 occured at higher rate than other pHs. Keywords: ZnO Nanoparticles, Semiconductor, Crystal growth, X-ray diffraction, Optical properties.
1. Introduction Nowadays water pollution and its consequences has become the world’s concern and many studies have focused on this area [1]. Due to the large-scale production and extensive applications, organic dyes have become a significant part of industrial wastewater [2]. Among the different ways for treatment of toxic and polluted water, using photocatalytic degradation process with nanometer semiconductors is an effective method. Even though most studies in this area have focused on TiO2, further investigation has shown that not only ZnO has similar efficiency of photocatalytic degradation but it is a better substitution to TiO2 in some applications [3-5]. Zinc oxide with a wurtzite hexagonal phase, a direct band gap of 3.37eV and large exciton binding energy of 60 meV is a promising material for use in photocatalytic degradation of water pollutants [6,7]. In this work, ZnO nanoparticles were synthesized via co-precipitation method and used as photocatalytic agent to decompose Eriochrome black-T dye (ECT) with the molecular formula of C20H12N3O7SNa. The chemical structure of the dye is shown in Fig. 1.
1
2. Experiments Zinc acetate dehydrate (ZnAC2.2H2O), ammonium carbonate ((NH4)2CO3) and absolute ethanol, with high purity, were purchased from Merck. ZnAC2.2H2O and (NH4)2CO3 were dissolved in deionized water to form two transparent solutions with 0.5M and 0.9M concentrations, respectively. The solutions were slowly mixed drop by drop in a beaker and rapidly stirred. After 4h, the performed precipitate was collected by filtration and washed with distilled water and ethanol. The product was finally dried at 60oC under vacuum for 3h. Afterwards the precipitate was calcined at 350oC for 3.5h to obtain ZnO nanoparticles. The structure of the products was studied by X-ray diffraction. The powder X-ray patterns were carried out using a PW-1840 Philips diffractometer at room temperature utilizing CuKα radiation wavelength of λ = 1.5418 Å. Fourier transforms infrared (FT-IR) analysis was performed using Bomem 450 with KBr method. The morphological characterizations of the samples were performed by a Hitachi field emission scanning electron microscope (FESEM) model S4160. All UV-vis analysis was measured using a GBC.Cintra 101 UV–vis spectrophotometer. The degradation experiments were carried out with a homemade photoreactor equipped with four 15W UV lamps, whose wavelengths were 256nm. The experiment was conducted with the initial dye concentration of 20 mg/l-1 and 0.05 g of identical ZnO nanoparticles. The photocatalyst was added to 100ml of the aqueous dye solution. The solution was stirred in dark till the adsorption equilibrium was obtained. The maximum equilibrium time was determined to be 30 min. Sample was placed in the reactor and exposed by the UV lamps. In order to determine the dye concentration by UV-vis spectropotometer, some irradiated solution was taken from the beaker at appropriate time and their suspended ZnO nanoparticles were collected by centrifugation.
3. Results and discussion Fig. 2(a) shows the X-ray patterns of a typical product. A comparison with the standard card demonstrates that the peaks can be indexed to know the hexagonal structure of ZnO with lattice constants of a=b=3.250Å and c=5.207Å (JCPDF: 79-2205) and no peaks from other ZnO phases or impurities are observed. Moreover, sharp peaks in X-ray diffraction pattern indicate the highly crystalline character of the products. A typical SEM image of the product is illustrated in Fig. 2(b). A careful perusal of this image shows that the product has almost spherical morphology with mean particle size of 20nm. Fig. 2(c) displays the FTIR spectra of products before and after calcination process. The peak which is observed around 500cm-1 is due to Zn-O bond vibrations of the particles. The second peak from
2
1300cm-1 to 1600cm-1 belongs to acetate ions, which is sharp in the spectrum of the precursor before calcination process. The third peak from 3200cm-1 to 3650 cm-1 is due to the O-H variation of water molecules. By comparison the graphs, it can be found that the intensity of peaks corresponding to the precursor decrease after calcination. Fig. 2(d) depicts the UV-Vis absorption spectrum of the ZnO nanopaticles. It can be seen that its maximum absorption wavelength is around 370nm. Photogeneration of electron–hole pair is generally responsible for degradation of dye pollutant in photocatalytic degradation process. Photogenerated h+ in the valence band reacts with either H2O or OH- to produce the HO• through the following reactions [8]:
h+ + H 2O → OH • + H + h + + OH − → OH •
(1)
(2)
while e- in the conduction band reacts with adsorbed O2 on the ZnO surface to generate O2•- and according to the following steps leads to generate HO• radicals [8]:
e− + O2 → O2• − + H + → HO2• + O2• − → HO2• + O−
(3)
HO2• → H 2O2 + O2
(4)
H 2O2 + O2•− → HO• + OH − + O2
(5)
H 2O2 + e− → HO• + OH −
(6)
H 2O2 + hν → 2 HO•
(7)
Dye + (O2• −orHO•orOHO2• ) → int ermediate → product
(8)
Fig. 3(a) depicts dye degradation over ZnO nanoparticles schematically. Fig. 3(b) shows the adsorption of ECB dye onto ZnO nanoparticles surface at different pHs. According to this column chart, the maximum adsorption of ECB dye takes place at pH 4 and is around 62%. Since the point of zero charge of photocatalyst varies with pH, the adsorption of dye on photocatalyst is different at various pH [9]. In view of the fact that decomposition of some dyes takes place on the surface of photocatalyst, the adsorption of dye is a crucial step in a photocatalytic degradation
3
process. Although the dye with high adsorption degrades faster, the effect sites for adsorbing the UV light decreases with increasing the adsorption. Moreover, higher pH value could provide higher concentration of hydroxyl ions to react with holes to form hydroxyl radicals which subsequently causes an enhanced photocatalytic decolorization rate of dyes [10]. The combined effect of the adsorption onto photocatalyst and the concentration of hydroxyl radicals will determine the extent of degradation. The relative concentration of dye decreases with increasing the illumination time so that the amount of degraded dye decreases with increasing the irradiation time and this is clearly seen in Fig. 3(c) which displays the percentage of dye degradation at each time for different pHs. The kinetics of photocatalytic degradation of organic dyes usually follows the Langmuir–Hinshelwood mechanism [11]:
r = − dC / dt = (kKC ) /(1 + KC )
(9)
where r is the degradation rate of the reactant (mg/L min), C is the concentration of the reactant (mg/L), t is the irradiation time, k is the reaction rate constant (mg/L min), K is the adsorption constant of the reactant (L/mg). When C is very small, the equation can be simplified to:
ln(C0 / C ) = kKt = K appt
(10)
where Kapp is the apparent first-order rate constant given by the slope of the graph of ln(Co/C) vs. t and Co is the initial concentration of the reactant. The plots of ln(C0/C) versus time for all pH are shown in Fig. 3(d). They are in agreement with the Langmuir-Hinshelwood first-order kinetic behavior. Fig. 4(a), 4(b), and 4(c) present the photocatalytic removal of ECB dye after 180min of UV irradiation at different pHs. More details are shown in C/Co versus time plot which is given in Fig. 4(d), where Co is the initial concentration of the dye, C is the concentration of the dye at irradiation time t (min). It can be seen that almost 75%, 83%, and 88% of ECB dye were degraded after 180min UV illumination at pH=4, pH=8, and pH=11 respectively. Although maximum adsorption occurs at pH=4, but ECB dye decomposes faster at pH=11. It may be said that adsorption at pH=4 is too high and causes more reduction of the effect sites for adsorption of the UV light. At pH=11 not only the effect sites are more than pH=4 but higher concentration of hydroxyl ions leads to higher concentration of hydroxyl radicals which causes an enhanced photocatalytic decolorization rate.
4. Conclusion
4
In summary, ZnO nanoparticles were synthesized via co-precipitation method and used to remove ECB dye. The photocatalytic degradation was performed at three pHs (4, 8, and 11). The results demonstrated that the adsorption of the dye onto ZnO nanoparticles surface, which has an important role in photocatalytic degradation, is strongly dependent on pH of the reaction solution. High decomposition rate occurred at pH=11 with the highest hydroxyl ions. Acknowledgment The authors would like to thank Shahid Chamran University for financial support. Reference [1] Q.I. Rahman, M. Ahmad, S.K Misra, M. Lohani, Mater Lett. 91 (2013) 170-174. [2] S.P. Buthelezi, A.O. Olaniran, B. Pillay, Molecules 17 (2012) 14260-14274. [3] A.M. Abdulkarem, E.M. Elssfah, Nan-Nan Yan, G. Demissie, Ying Yu, J. Phys Chem Solids. 74 (2013) 647652. [4] F. Tian, Y. Liu, Scripta Mater. 69 (2013) 417-419. [5] X. Cai, Y. Cai, Y. Liu, H. Li, F. Zhang, Y. Wang, J. Phys Chem Solids. 74 (2013) 1196-1203. [6] I. Kazeminezhad, A. Sadollahkhani, M. Farbod, Mater Lett. 92 (2013) 29-32. [7] A. Echresh, M. Zargar Shoushtari and M. Farbod . Mater Lett. 110 (2013) 164-167. [8] S.M. Lam, J.C. Sin, A.Z. Abdullah, A.R. Mohamed, Desalination. 41 (2012) 131-169. [9] U.G. Akpan, B.H. Hameed, J Hazard Mater. 170 ( 2009) 520-529. [10] L. Gomathi, K. Mohan Reddy, Appl Surf Sci. 256 (2010) 3116-3121. [11] K. Vignesh, A. Suganthi, M. Rajarajan, S.A. Sara, Powder Technol. 224 (2012) 331-337. Figure captions Fig. 1. Chemical structure of Eriochrome black-T dye. Fig. 2. (a) XRD pattern, (b) SEM image, (c) FTIR spectra, and (d) UV-visible spectrum of ZnO nanoparticles. Fig. 3. (a) Schematic illustration of dye degradation over ZnO nanoparticles, (b) adsorption of ECB dye onto ZnO surface at different pH, percentage of ECB dye degradatin as a function of time, and (d) the plot of ln(C0/C) versus time. Fig. 4. UV–vis spectra of ECB dye solution in 30 min intervals at (a) pH=4, (b) pH=8 and (c) pH=11. (d) The plot of C/C0 versus reaction time at various pH.
5
Fig. 1.
Fig. 2.
6
Fig. 3.
7
Fig. 4.
8
photocatalytic degradation of Eriochrome black dye using ZnO nanoparticles
Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz,
Highlight ¾ ZnO nanoparticles were synthesized via precipitation method. ¾ The results confirmed that the samples have hexagonal phase and their average mean
size were obtained down to 20 nm. ¾ The photocatalytic degradation of Eriochrome black-T dye was studied using the
particles within different pH solutions.
9
Graphical Abstract (for review)
photocatalytic degradation of Eriochrome black dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz,
Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani
www.elsevier.com/locate/matlet
PII: DOI: Reference:
S0167-577X(14)00134-7 http://dx.doi.org/10.1016/j.matlet.2014.01.118 MLBLUE16372
To appear in:
Materials Letters
Received date: 16 November 2013 Accepted date: 21 January 2014 Cite this article as: Iraj Kazeminezhad, Azar Sadollahkhani, Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles, Materials Letters, http://dx.doi.org/10.1016/j.matlet.2014.01.118 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Photocatalytic degradation of Eriochrome black-T dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz, Iran *
Corresponding author:
Email: [email protected], [email protected] Telefax: +98(611)3331040
Abstract In this study, ZnO nanoparticles were synthesized by co-precipitation method. The particles were used for degradation of Eriochrome black-T dye by examination at three different pH values. It was observed that the adsorption of dye onto ZnO nanoparticles surface is strongly dependent on the pH of the solution which plays an important role in photocatalytic degradation. Decomposition of Eriochrome black-T dye at pH 11 occured at higher rate than other pHs. Keywords: ZnO Nanoparticles, Semiconductor, Crystal growth, X-ray diffraction, Optical properties.
1. Introduction Nowadays water pollution and its consequences has become the world’s concern and many studies have focused on this area [1]. Due to the large-scale production and extensive applications, organic dyes have become a significant part of industrial wastewater [2]. Among the different ways for treatment of toxic and polluted water, using photocatalytic degradation process with nanometer semiconductors is an effective method. Even though most studies in this area have focused on TiO2, further investigation has shown that not only ZnO has similar efficiency of photocatalytic degradation but it is a better substitution to TiO2 in some applications [3-5]. Zinc oxide with a wurtzite hexagonal phase, a direct band gap of 3.37eV and large exciton binding energy of 60 meV is a promising material for use in photocatalytic degradation of water pollutants [6,7]. In this work, ZnO nanoparticles were synthesized via co-precipitation method and used as photocatalytic agent to decompose Eriochrome black-T dye (ECT) with the molecular formula of C20H12N3O7SNa. The chemical structure of the dye is shown in Fig. 1.
1
2. Experiments Zinc acetate dehydrate (ZnAC2.2H2O), ammonium carbonate ((NH4)2CO3) and absolute ethanol, with high purity, were purchased from Merck. ZnAC2.2H2O and (NH4)2CO3 were dissolved in deionized water to form two transparent solutions with 0.5M and 0.9M concentrations, respectively. The solutions were slowly mixed drop by drop in a beaker and rapidly stirred. After 4h, the performed precipitate was collected by filtration and washed with distilled water and ethanol. The product was finally dried at 60oC under vacuum for 3h. Afterwards the precipitate was calcined at 350oC for 3.5h to obtain ZnO nanoparticles. The structure of the products was studied by X-ray diffraction. The powder X-ray patterns were carried out using a PW-1840 Philips diffractometer at room temperature utilizing CuKα radiation wavelength of λ = 1.5418 Å. Fourier transforms infrared (FT-IR) analysis was performed using Bomem 450 with KBr method. The morphological characterizations of the samples were performed by a Hitachi field emission scanning electron microscope (FESEM) model S4160. All UV-vis analysis was measured using a GBC.Cintra 101 UV–vis spectrophotometer. The degradation experiments were carried out with a homemade photoreactor equipped with four 15W UV lamps, whose wavelengths were 256nm. The experiment was conducted with the initial dye concentration of 20 mg/l-1 and 0.05 g of identical ZnO nanoparticles. The photocatalyst was added to 100ml of the aqueous dye solution. The solution was stirred in dark till the adsorption equilibrium was obtained. The maximum equilibrium time was determined to be 30 min. Sample was placed in the reactor and exposed by the UV lamps. In order to determine the dye concentration by UV-vis spectropotometer, some irradiated solution was taken from the beaker at appropriate time and their suspended ZnO nanoparticles were collected by centrifugation.
3. Results and discussion Fig. 2(a) shows the X-ray patterns of a typical product. A comparison with the standard card demonstrates that the peaks can be indexed to know the hexagonal structure of ZnO with lattice constants of a=b=3.250Å and c=5.207Å (JCPDF: 79-2205) and no peaks from other ZnO phases or impurities are observed. Moreover, sharp peaks in X-ray diffraction pattern indicate the highly crystalline character of the products. A typical SEM image of the product is illustrated in Fig. 2(b). A careful perusal of this image shows that the product has almost spherical morphology with mean particle size of 20nm. Fig. 2(c) displays the FTIR spectra of products before and after calcination process. The peak which is observed around 500cm-1 is due to Zn-O bond vibrations of the particles. The second peak from
2
1300cm-1 to 1600cm-1 belongs to acetate ions, which is sharp in the spectrum of the precursor before calcination process. The third peak from 3200cm-1 to 3650 cm-1 is due to the O-H variation of water molecules. By comparison the graphs, it can be found that the intensity of peaks corresponding to the precursor decrease after calcination. Fig. 2(d) depicts the UV-Vis absorption spectrum of the ZnO nanopaticles. It can be seen that its maximum absorption wavelength is around 370nm. Photogeneration of electron–hole pair is generally responsible for degradation of dye pollutant in photocatalytic degradation process. Photogenerated h+ in the valence band reacts with either H2O or OH- to produce the HO• through the following reactions [8]:
h+ + H 2O → OH • + H + h + + OH − → OH •
(1)
(2)
while e- in the conduction band reacts with adsorbed O2 on the ZnO surface to generate O2•- and according to the following steps leads to generate HO• radicals [8]:
e− + O2 → O2• − + H + → HO2• + O2• − → HO2• + O−
(3)
HO2• → H 2O2 + O2
(4)
H 2O2 + O2•− → HO• + OH − + O2
(5)
H 2O2 + e− → HO• + OH −
(6)
H 2O2 + hν → 2 HO•
(7)
Dye + (O2• −orHO•orOHO2• ) → int ermediate → product
(8)
Fig. 3(a) depicts dye degradation over ZnO nanoparticles schematically. Fig. 3(b) shows the adsorption of ECB dye onto ZnO nanoparticles surface at different pHs. According to this column chart, the maximum adsorption of ECB dye takes place at pH 4 and is around 62%. Since the point of zero charge of photocatalyst varies with pH, the adsorption of dye on photocatalyst is different at various pH [9]. In view of the fact that decomposition of some dyes takes place on the surface of photocatalyst, the adsorption of dye is a crucial step in a photocatalytic degradation
3
process. Although the dye with high adsorption degrades faster, the effect sites for adsorbing the UV light decreases with increasing the adsorption. Moreover, higher pH value could provide higher concentration of hydroxyl ions to react with holes to form hydroxyl radicals which subsequently causes an enhanced photocatalytic decolorization rate of dyes [10]. The combined effect of the adsorption onto photocatalyst and the concentration of hydroxyl radicals will determine the extent of degradation. The relative concentration of dye decreases with increasing the illumination time so that the amount of degraded dye decreases with increasing the irradiation time and this is clearly seen in Fig. 3(c) which displays the percentage of dye degradation at each time for different pHs. The kinetics of photocatalytic degradation of organic dyes usually follows the Langmuir–Hinshelwood mechanism [11]:
r = − dC / dt = (kKC ) /(1 + KC )
(9)
where r is the degradation rate of the reactant (mg/L min), C is the concentration of the reactant (mg/L), t is the irradiation time, k is the reaction rate constant (mg/L min), K is the adsorption constant of the reactant (L/mg). When C is very small, the equation can be simplified to:
ln(C0 / C ) = kKt = K appt
(10)
where Kapp is the apparent first-order rate constant given by the slope of the graph of ln(Co/C) vs. t and Co is the initial concentration of the reactant. The plots of ln(C0/C) versus time for all pH are shown in Fig. 3(d). They are in agreement with the Langmuir-Hinshelwood first-order kinetic behavior. Fig. 4(a), 4(b), and 4(c) present the photocatalytic removal of ECB dye after 180min of UV irradiation at different pHs. More details are shown in C/Co versus time plot which is given in Fig. 4(d), where Co is the initial concentration of the dye, C is the concentration of the dye at irradiation time t (min). It can be seen that almost 75%, 83%, and 88% of ECB dye were degraded after 180min UV illumination at pH=4, pH=8, and pH=11 respectively. Although maximum adsorption occurs at pH=4, but ECB dye decomposes faster at pH=11. It may be said that adsorption at pH=4 is too high and causes more reduction of the effect sites for adsorption of the UV light. At pH=11 not only the effect sites are more than pH=4 but higher concentration of hydroxyl ions leads to higher concentration of hydroxyl radicals which causes an enhanced photocatalytic decolorization rate.
4. Conclusion
4
In summary, ZnO nanoparticles were synthesized via co-precipitation method and used to remove ECB dye. The photocatalytic degradation was performed at three pHs (4, 8, and 11). The results demonstrated that the adsorption of the dye onto ZnO nanoparticles surface, which has an important role in photocatalytic degradation, is strongly dependent on pH of the reaction solution. High decomposition rate occurred at pH=11 with the highest hydroxyl ions. Acknowledgment The authors would like to thank Shahid Chamran University for financial support. Reference [1] Q.I. Rahman, M. Ahmad, S.K Misra, M. Lohani, Mater Lett. 91 (2013) 170-174. [2] S.P. Buthelezi, A.O. Olaniran, B. Pillay, Molecules 17 (2012) 14260-14274. [3] A.M. Abdulkarem, E.M. Elssfah, Nan-Nan Yan, G. Demissie, Ying Yu, J. Phys Chem Solids. 74 (2013) 647652. [4] F. Tian, Y. Liu, Scripta Mater. 69 (2013) 417-419. [5] X. Cai, Y. Cai, Y. Liu, H. Li, F. Zhang, Y. Wang, J. Phys Chem Solids. 74 (2013) 1196-1203. [6] I. Kazeminezhad, A. Sadollahkhani, M. Farbod, Mater Lett. 92 (2013) 29-32. [7] A. Echresh, M. Zargar Shoushtari and M. Farbod . Mater Lett. 110 (2013) 164-167. [8] S.M. Lam, J.C. Sin, A.Z. Abdullah, A.R. Mohamed, Desalination. 41 (2012) 131-169. [9] U.G. Akpan, B.H. Hameed, J Hazard Mater. 170 ( 2009) 520-529. [10] L. Gomathi, K. Mohan Reddy, Appl Surf Sci. 256 (2010) 3116-3121. [11] K. Vignesh, A. Suganthi, M. Rajarajan, S.A. Sara, Powder Technol. 224 (2012) 331-337. Figure captions Fig. 1. Chemical structure of Eriochrome black-T dye. Fig. 2. (a) XRD pattern, (b) SEM image, (c) FTIR spectra, and (d) UV-visible spectrum of ZnO nanoparticles. Fig. 3. (a) Schematic illustration of dye degradation over ZnO nanoparticles, (b) adsorption of ECB dye onto ZnO surface at different pH, percentage of ECB dye degradatin as a function of time, and (d) the plot of ln(C0/C) versus time. Fig. 4. UV–vis spectra of ECB dye solution in 30 min intervals at (a) pH=4, (b) pH=8 and (c) pH=11. (d) The plot of C/C0 versus reaction time at various pH.
5
Fig. 1.
Fig. 2.
6
Fig. 3.
7
Fig. 4.
8
photocatalytic degradation of Eriochrome black dye using ZnO nanoparticles
Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz,
Highlight ¾ ZnO nanoparticles were synthesized via precipitation method. ¾ The results confirmed that the samples have hexagonal phase and their average mean
size were obtained down to 20 nm. ¾ The photocatalytic degradation of Eriochrome black-T dye was studied using the
particles within different pH solutions.
9
Graphical Abstract (for review)
photocatalytic degradation of Eriochrome black dye using ZnO nanoparticles Iraj Kazeminezhad, Azar Sadollahkhani* Nanotechnology Lab, Department of Physics, Shahid Chamran University, Ahvaz,