Effect of Reaction Time on the Morphology and Photocatalytic Property of ZnO Nanoparticles

2017 ◽  
Vol 726 ◽  
pp. 365-369
Author(s):  
Xia Kong ◽  
Ya Wei Hu ◽  
Wei Pan

Abstract. ZnO nanoparticles with different morphology were synthesized through a one-step and low temperature hydrothermal method with different reaction time. The prepared ZnO nanoparticles have been used as photocatalysts for the degradation of methylene blue (MB) aqueous solution under UV irradiation to study the relationship between the morphology and photocatalytic performance. The phase, crystallographic structure and morphology of synthesised ZnO nanoparticles were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The photocatalytic activity of ZnO nanoparticles were carried out by UV-visible spectroscopy (UV-vis). SEM results showed that different particle sizes and morphologies of flower-like, elliptical-shape and rod-shapes were obtained at 60 °C for 1 h, 4 h, 8 h and 12 h, which promoted photodegradation of methylene blue (MB) aqueous solution under UV light irradiation. Especially, elliptical-shape ZnOnanoparticles with reaction time of 4 h were most efficient, and the degradation rate was up to 98.2% after 20 min UV irradiation.

2011 ◽  
Vol 194-196 ◽  
pp. 385-388
Author(s):  
Hong Juan Wang ◽  
Feng Qiang Sun ◽  
Ming Zhong Ren ◽  
Qing Wei Guo

Nanoporous SnO2with high photocatalytic activity has been successfully prepared by a photochemical method, using SnCl2aqueous solution as a precursor. The as-synthesized sample was characterized by XRD, N2 adsorption-desorption and UV-vis. The photocatalytic activity of the sample was evaluated by degrading methylene blue (MB) aqueous solution under the UV light source and was compared with that of the commercial titania (Degussa P25). The results showed that the produced SnO2can degrade MB solution quickly and has comparative photocatalytic performance with P25 for degrading MB. This facile method supplies an effective way to prepare SnO2photocatalyst.


2014 ◽  
Vol 895 ◽  
pp. 547-557 ◽  
Author(s):  
T.K. Tan ◽  
P.S. Khiew ◽  
W.S. Chiu ◽  
S. Radiman ◽  
R. Abd-Shukor ◽  
...  

The commercialized ZnO nanopowder has been employed in this study to investigate the photocatalytic degradation of two organic compounds, Methylene Blue (MB) and Phenol Red (PR) in an aqueous suspension of ZnO nanoparticles under UV light irradiation. This study has considered ZnO as the photocatalyst because it has been reported as a suitable substitute for TiO2 in certain application. For the characterization of the ZnO photocatalyst, X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area analysis (BET), and UV-visible spectroscopy were exploited. X-ray diffractometry result for the ZnO nanoparticles exhibit normal crystalline phase features. All observed peaks can be indexed to the pure hexagonal wurtzite crystal structures, with the space group of P63mc. From the XRD pattern, no diffraction peaks from other impurities have been observed. In addition, TEM measurement shows that most of the nanoparticles are spherical and rod-like in shape and fairly monodispersed. A significant degradation of the organic compounds were observed in the presence of the catalyst without the irradiation of the UV light and the degradation increases significantly when irradiated with the UV light for a certain period of time. Besides, for the same period of irradiation, the photodegradation of the organic compounds was increased as the photocatalyst loading increases. The BET measurement for ZnO was 11.9 m2/g. The effect of some parameters such as initial concentration of organic compounds and photocatalyst loading were also determined. Keywords: Nanostructures; Methylene blue; Phenol red; Zinc oxide; Heterogeneous photocatalyst


Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2360
Author(s):  
Seyedehmaryam Moosavi ◽  
Rita Yi Man Li ◽  
Chin Wei Lai ◽  
Yusliza Yusof ◽  
Sinyee Gan ◽  
...  

In this study, activated carbon (AC) from coconut shell, as a widely available agricultural waste, was synthesised in a simple one-step procedure and used to produce a magnetic Fe3O4/AC/TiO2 nano-catalyst for the degradation of methylene blue (MB) dye under UV light. Scanning electron microscopy revealed that TiO2 nanoparticles, with an average particle size of 45 to 62 nm, covered the surface of the AC porous structure without a reunion of its structure, which according to the TGA results enhanced the stability of the photocatalyst at high temperatures. The photocatalytic activities of synthesised AC, commercial TiO2, Fe3O4/AC, and Fe3O4/AC/TiO2 were compared, with Fe3O4/AC/TiO2 (1:2) exhibiting the highest catalytic activity (98%). Furthermore, evaluation of the recovery and reusability of the photocatalysts after treatment revealed that seven treatment cycles were possible without a significant reduction in the removal efficiency.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Abdul Rahman ◽  
M. T. M. Ayob ◽  
S. Radiman

ZnO nanowhiskers were used for photodecomposition of methylene blue in aqueous solution under UV irradiation. The rate of methylene blue degradation increased linearly with time of UV irradiation. 54% of degradation rate was observed when the ZnO nanowhiskers were used as photocatalysts for methylene blue degradation for 80 min under UV irradiation. The decoration of p-type NiO nanoparticles on n-type ZnO nanowhiskers significantly enhanced photocatalytic activity and reached 72% degradation rate of methylene blue by using the same method. NiO-decorated ZnO was recycled for second test and shows 66% degradation from maximal peak of methylene blue within the same period. The increment of photocatalytic activity of NiO-decorated ZnO nanowhiskers was explained by the extension of the electron depletion layer due to the formation of nanoscale p-n junctions between p-type NiO and n-type ZnO. Hence, these products provide new alternative proficient photocatalysts for wastewater treatment.


2015 ◽  
Vol 1123 ◽  
pp. 316-321 ◽  
Author(s):  
Vici Tritella Carmida ◽  
Mia Putri Rahmawati ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh

In this study, the photocatalytic degradation of methylene blue and congo red has been investigated using montmorillonite modified Cr-doped ZnO nanoparticles. Chromium doped zinc oxide nanoparticles were synthesized by co-precipitation method and were characterized using X-ray diffraction, Fourier-transform infrared absorption and UV-visible spectrophotometer. Furthermore these nanoparticles were explored to degradation of methylene blue and congo red in aqueous solution as model of organic pollutant under UV light irradiation. Comparison of degradation efficiency demonstrated that Cr-doped ZnO nanoparticles modified montmorillonite exhibited higher activity than pure Cr-doped ZnO.


2013 ◽  
Vol 726-731 ◽  
pp. 429-434
Author(s):  
Wei Wang ◽  
Chun Hua Lu ◽  
Ya Ru Ni ◽  
Zhong Zi Xu

Anatase TiO2 nanosheets with different percentage of exposed high-reactive {001} facets were synthesized successfully. Besides the FESEM and TEM anslysis, XRD, Raman, and PL analysis were also conducted systematically to give a new insight on analyzing the as-prepared {001} facets dominated TiO2 photocatalysts. Photocatalytic activities of the photocatalysts were tested by the degradation of methylene blue (MB) aqueous solution under UV irradiation. The results indicated that there was an optimal percentage of the exposed {001} facets existed to give the highest photocatalytic activity of as-prepared TiO2 nanosheets. A possible mechanism for the enhanced photocatalytic activity of the {001} facets dominated anatase TiO2 was also proposed.


2013 ◽  
Vol 634-638 ◽  
pp. 76-80
Author(s):  
Wei Hu ◽  
Shen Xin Li ◽  
Cheng Duan Wang

The decolourization of dye wastewater by persulfate was studied using methylene blue as a model dye wastewater. Effects of several parameters, such as dose of oxidant, ionic strength, pH, temperature and UV irradiation, were investigated in detail. The results showed that the decolourization reaction of methylene blue by persulfate could be fitted to a pseudo-first order kinetics model. In addition, when the oxidant amount used is 2 times of methylene blue, pH 3.43 and reaction temperature for 60°C, after uv light under the irradiation of 20 min, methylene blue decolorization rate can reach more than 98%. The results are useful for the treatment of dye wastewater.


2016 ◽  
Vol 868 ◽  
pp. 28-32 ◽  
Author(s):  
Tomoyo Goto ◽  
Tohru Sekino

In this study, we synthesized the TiO2-modified hydroxyapatite (HAp) with various morphologies by hydrothermal treatment using urea decomposition, at 160 oC for 6 h. After hydrothermal treatment, carbonate-substituted HAp and TiO2 (anatase) phases were formed in products using 1.0-0.1 M urea solution. The morphology of synthesized HAp changed from small plate-shaped to long needle-shaped crystals with decreasing the urea concentration. The photocatalytic property for samples was investigated by decoloration test using 25 ppm methylene blue solution. In comparison with HAp samples without TiO2, the TiO2-modified HAp clearly showed the photocatalytic decomposition of methylene blue by UV irradiation.


Author(s):  
An Nang Vu ◽  
Anh Mai Tran ◽  
Nghi Tuyet Nguyen ◽  
Duyen My Ngoc Lam ◽  
Phong Pham Nam Le ◽  
...  

In this work, nanohybrid of zinc oxide/ cellulose nanocrystals (ZnO/CNC) was successfully prepared by using a low cost and green method for photocatalytic degradation of methylene blue (MB). CNC had been derived through the hydrolysis reaction by citric/hydrochloric acid from the pure cellulose isolated from Vietnamese Nypa fruticans trunk. The obtained CNC with carboxyl groups could act as a stabilizing and supporting agent to anchor ZnO nanoparticles. The chemical and crystal structures, morphology, thermal and photocatalytic properties of the ZnO/CNC nanohybrid were characterized by FESEM, FTIR, XRD, FESEM, BET, EDX, TGA, DRS and photocatalytic tests. Analyses of FTIR spectra, XRD, and FESEM indicated that the ZnO nanocrystals with the size of 50 nm formed and loaded on the surface of CNC. The TGA analysis demonstrated that the ZnO loading sample (ZnO/CNC) had the thermal degradation onset temperature higher than that of neat CNC. ZnO/CNC cuold be absorpted ultraviolet light and have high value of specific surface area (SBET), based on the DRS spectra and the nitrogen adsorption – desorption isotherms analysis, respectively. ZnO/CNC displayed more photocatalytic activity than pure ZnO upon degradation of methylene blue due to strong interaction between the CNC and ZnO nanoparticles. The maximum degradation of MB was about 95% in 150 minutes for the ZnO/CNC.


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