scholarly journals Microwave-assisted biosynthesis and characterization of ZnO film for photocatalytic application in methylene blue degradation

2021 ◽  
Vol 6 (2) ◽  
pp. 69-73
Author(s):  
Ari Sulistyo Rini ◽  
Averin Nabilla ◽  
Yolanda Rati

This study aims to investigate the physical characteristics and photocatalyst activity of biosynthesized ZnO with pineapple (Ananas comosus) peel extract under microwave irradiation. The ZnO powder was prepared in two different concentrations of zinc nitrate hexahydrate (ZNH) at 200mM (Z-200) and 500 mM (Z-500). The optical, structural, and morphological properties of ZnO were analyzed using UV-Vis spectroscopy, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM), respectively. The UV-Vis absorption spectrum showed a wide absorbance peak of ZnO at the wavelength of 300-360 nm with a bandgap energy of 3.22 and 3.25 eV. The XRD result confirmed the wurtzite structure of ZnO with high crystallinity. SEM morphology showed spherical particles with an average particle size of 190-220 nm. For photocatalytic application, ZnO film was fabricated via the doctor blade method from microwave-assisted biosynthesized ZnO powder. ZnO films were then applied under UV-irradiation to examine the photocatalytic degradation of methylene blue. It was found that the catalytic behavior of ZnO film was affected by the starting ZNH concentration with maximum effectiveness of 46% degradation after 2 h.

Technologies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 7 ◽  
Author(s):  
Le Ngoc Liem ◽  
Nguyen Phuoc The ◽  
Dieu Nguyen

In this work, silver nanoparticles (AgNPs) were synthesized quickly and in an eco-friendly manner using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemicals (Yuet et al. Int. J. Nanomed. 2012, 7, 4263–4267; Krishnakuma and Adavallan. Adv. Nat. Sci. Nanosci. Nanotechnol. 2014, 5, 025018). The Mulberry leaves extract functions as both a stabilizing and reducing agent. The UV-Vis spectroscopy shows a peak maximum at 430 nm. The transmission electron microscopy (TEM) image illustrated of synthesized AgNPs were nearly spherical-shaped particles whose sizes range from 15 to 20 nm. The TEM image of Nano Silver solution sample synthesized by the microwave assisted method shows nearly spherical particles, with an average particle size estimated at 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by the microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. The UV-Vis spectrum of AgNPsmw after two months of storage shows negligible peak changes of silver nanoparticles.


2020 ◽  
Vol 979 ◽  
pp. 175-179
Author(s):  
M. Nagalakshmi ◽  
N. Anusuya ◽  
S. Karuppuchamy

Titanium dioxide (TiO2) nanoparticles have been successfully prepared by biological method and the resulting material was characterized by XRD, FTIR, SEM, EDAX and UV-Vis spectroscopy. The synthesized TiO2 materials successfully degraded the methylene blue dye (MB) under UV light irradiation.


2020 ◽  
Vol 62 ◽  
pp. 87-95
Author(s):  
Hichem Farh ◽  
Abdelouahab Noua ◽  
Rebai Guemini ◽  
Djamal Eldine Guitoume ◽  
Oussama Zaoui

In this work, we studied the ZnO film thickness effect on the photocatalytic performance of n-ZnO/p-NiO heterostructures. The ZnO and NiO films were prepared by sol-gel dip-coating technique and the thickness of the ZnO film was varied by changing the number of coatingsfrom 2 to12. The formation of the p-NiO/n-ZnO heterostructure was confirmed by X ray diffraction (XRD). The obtained ZnO films present a wurtzite structure with a preferred orientation along (002) direction while the NiO film present a cubic structure highly oriented along (200) direction. UV-visible transmittance spectra of the prepared heterostructures revealed a good transparency in the visible region. The photocatalytic propertiesof the n-ZnO/p-NiO heterostructures were investigated by measuring the degradation rate of methylene blue. All the samples exhibit a good photocatalytic activity under solar light irradiation. The photocatalytic activity of p-NiO/n-ZnO heterostructureswas strongly correlated with the number of ZnO coatings. The highest photocatalytic activity was obtained at 6 coatings with a degradation rate of methylene blue equal to 98.67% for 4.5h of irradiation.


Author(s):  
Liem Le ◽  
The Nguyen ◽  
Dieu Nguyen

In this work, silver nanoparticles (AgNPs) were synthesized rapidly and eco-friendlily using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemical [1,2]. The Mulberry leaves extract acts as both reducing agent and stabilizing agent. The UV-Vis spectrum shows peak at 430 nm. The TEM image of synthesized AgNPs sample shows spherical shaped particles whose size range from 15 to 20 nm. TEM image of nano silver solution sample synthesized by microwave assisted method shows nearly spherical particles with an average particle size of 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. After two month storage of AgNPsmw, the absorption spectrum of AgNPsmw was taken again. The UV-Vis spectrum shows negligible peak changes of silver nanoparticles have occurred after two months of storage. The synthesized AgNPs material could be used as an antimicrobial, used in the field of textile and in wastewater treatment.


2007 ◽  
Vol 1035 ◽  
Author(s):  
Ken-ichi Ogata ◽  
Kazuto Koike ◽  
Shigehiko Sasa ◽  
Masataka Inoue ◽  
Mitsuaki Yano

AbstractZnO nanorods synthesis on a glass substrate coated with ZnO film was performed by means of microwave-assisted heating. Nanorod structure was dependent on the underlying ZnO films; slightly tilted nanorods about 800nm diameter were synthesized on an as-sputtered ZnO film while highly c-axis oriented ones about 100nm diameter were developed on the ZnO film after annealing. Photoluminescence spectra of the ZnO nanorods at 6K showed a badedge excitonic emission with comparable intensity to a visible defect related emission, suggesting the existence of many radiative defects which would be originated from insufficient quality of the underlying ZnO layer. Pattered photoresist layer can successfully be utilized for synthesis of the ZnO nanolods in selective area.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1682
Author(s):  
Maymounah N. Alharthi ◽  
Iqbal Ismail ◽  
Stefano Bellucci ◽  
Nezar H. Khdary ◽  
Mohamed Abdel Salam

The present work is intended to biosynthesize zinc oxide nanoparticles (ZnO NPs) via facile and modern route using aqueous Ziziphus jujuba leaves extract assisted by microwave and explore their photocatalytic degradation of methyl orange anionic dye and methylene blue cationic dye under solar irradiation. The biosynthesized microwave assisted ZnO NPs were characterized and the results showed that ZnO NPs contain hexagonal wurtzite and characterized with a well-defined spherical-like shape with an outstanding band gap (2.70 eV), average particle size of 25 nm and specific surface area of 11.4 m2/g. The photocatalytic degradation of the MO and MB dyes by biosynthesized ZnO NPs under solar irradiation was studied and the results revealed the selective nature of the ZnO NPs for the adsorption and further photocatalytic degradation of the MO dye compared to the MB dye. In addition, the photocatalytic degradation of MO and MB dyes by the ZnO NPs under solar radiation was fitted by the first-order kinetics. Moreover, the photodegradation mechanism proposed that superoxide ions and hydroxyl radicals are the main reactive species.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 305
Author(s):  
Alia Raees ◽  
Muhammad Asghar Jamal ◽  
Ikram Ahmed ◽  
Mika Silanpaa ◽  
Tahani Saad Algarni

Removal of hazardous organic dyes from polluted water bodies requires the introduction of strong adsorbents and photocatalysts to industrial wastewaters. Herein, photocatalytic CeO2 nanoparticles and CeO2/CuO nanocomposite were synthesized following a co-precipitation method for low cost elution of methylene blue (MB) from water. The crystallinity and surface structure of the as-prepared materials have been analyzed using characterization techniques including X-ray powder diffraction (XRPD), field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), ultra-violet visible spectroscopy (UV–Vis), and Fourier-transform infrared spectroscopy (FTIR). The average particle size of both the nano scaled samples were approximately 20–30 nm. The photocatalytic properties of CeO2/CuO were investigated under visible light against methylene blue (MB). The results showed 91% photodegradation of MB organic pollutant in 3 h as monitored by UV–Vis spectroscopy. Absorbance peaks appeared at around 670 nm corresponding to degradation of MB. Such output displayed the effectiveness of Ce nanocomposites for environmental benefits. Hence, CeO2/CuO nanocomposite could be useful for treatment of industrial wastewaters by removing hazardous MB dye.


2016 ◽  
Vol 12 (6) ◽  
pp. 4127-4133
Author(s):  
Nazmul Kayes ◽  
Jalil Miah ◽  
Md. Obaidullah ◽  
Akter Hossain ◽  
Mufazzal Hossain

Photodegradation of textile dyes in the presence of an aqueous suspension of semiconductor oxides has been of growing interest. Although this method of destruction of dyes is efficient, the main obstacle of applying this technique in the industry is the time and cost involving separation of oxides from an aqueous suspension. In this research, an attempted was made to develop ZnO films on a glass substrate by simple immobilization method for the adsorption and photodegradation of a typical dye, Remazol Red R (RRR) from aqueous solution. Adsorption and photodegradation of  RRR were performed in the presence of glass supported ZnO film. Photodegradation of the dye was carried out by varying different parameters such as the catalyst dosage, initial concentrations of RRR, and light sources. The percentage of adsorption as well as photodegradation increased with the amount of ZnO, reaches a maximum and then decreased. Maximum degradation has been found under solar light irradiation as compared to UV-light irradiation. Removal efficiency was also found to be influenced by the pre-sonication of ZnO suspension.


Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1,the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K,the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.


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