scholarly journals A facile synthesis of MgFe2O4/ZnS heterojunction with effectively enhanced visible light photocatalytic activity for degradation of methylene blue and crystal violet dyes

Author(s):  
Rajkumar S ◽  
Seetharaman S ◽  
Vijayan V ◽  
Sivaraj M ◽  
Chandran M ◽  
...  

Abstract A novel n-MgFe2O4–n-ZnS heterojunction catalyst was employed via two step approach for photodegradation of organic dyes such as methylene blue (MB) and crystal violet (CV) dyes under visible light irradiation. The synthesized MgFe2O4/ZnS NCs were characterized using PXRD, FTIR, UV-visible spectroscopy, PL and FESEM analysis which reveals the formation of flake like structure with size as to be ~50 nm. The photocatalytic experimental result demonstrates that the MgFe2O4/ZnS nanocomposites (NCs) improve photodegradation performance with 98.0% and 91% decomposition of MB and CV dyes within 120 min illumination during simulated visible light irradiation. From the result, MgFe2O4/ZnS NCs has higher photocatalytic performance than that of MgFe2O4, and ZnS due to efficient separation of the photo-induced electron-hole pairs and effective electron–hole generation transfer by the formation of n-MgFe2O4–n-ZnS heterojunction. Hence, photodegradation performance implies that the synthesized MgFe2O4/ZnS NCs can be effectively utilized in waste water purification systems.

2017 ◽  
Vol 41 (13) ◽  
pp. 5334-5346 ◽  
Author(s):  
Chao Liang ◽  
Cheng-Gang Niu ◽  
Xiao-Ju Wen ◽  
Shi-Feng Yang ◽  
Mao-Cai Shen ◽  
...  

The Ag@AgCl nanoparticles could broaden visible-light absorption of pure CSH and depress the recombination of photoinduced electron–hole pairs.


2021 ◽  
Vol 55 (3-4) ◽  
pp. 365-373
Author(s):  
MOHAMED EL-SAKHAWY ◽  
AHMED SALAMA ◽  
AHMED K. EL-ZIATY ◽  
HAZEM HASSAN

"Photo-catalytic degradation of organic dyes in aquatic environments under visible light irradiation affords an efficient and economic technique for environmental remediation. TEMPO-oxidized cellulose nanofibers/zinc oxide nanocomposite (TEMPO-CNF/ZnO) was prepared through oxidation of cellulose pulp, followed by zinc oxide precipitation in the presence of oxidized fibers. TEMPO-CNF/ZnO was characterized by different techniques. The degradation rate of methylene blue (MB) by TEMPO-CNF/ZnO was gradually increased with increasing pH and the degradation reached 86% within 340 minutes at pH 7. The kinetic study showed that the pseudo-first-order kinetic best fitted the photo-catalytic process. A mechanism was proposed for the degradation of MB using TEMPO-CNF/ZnO under visible light irradiation. TEMPO-CNF/ZnO showed high antibacterial activity against S. aureus and E. coli. Thus, the TEMPO-CNF/ZnO nanocomposite has been demonstrated to be an effective photo-catalytic material for degrading MB under visible light irradiation."


RSC Advances ◽  
2017 ◽  
Vol 7 (38) ◽  
pp. 23432-23443 ◽  
Author(s):  
Lu-Lu Shi ◽  
Tian-Rui Zheng ◽  
Min Li ◽  
Lin-Lu Qian ◽  
Bao-Long Li ◽  
...  

Five-coordinated copper(ii) coordination polymers 1–5 are highly efficient and universal photocatalysts for the degradation of the organic dyes methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) under visible light irradiation.


Author(s):  
Muhammad Amirul Islam ◽  
Iqbal Ahmed Siddiquey ◽  
Md. Azizur Rahman Khan ◽  
Md. Mahbubul Alam ◽  
Saiful S.M. Islam ◽  
...  

Photocatalytic degradation of a heteropolyaromatic dye (methylene blue) in aqueous ZnO suspension was investigated under UV and visible light irradiation. Adsorption behavior was found to be well fitted with the Langmuir and Freundlich isotherms. Free energy of adsorption was found to be negative which indicates that adsorption was spontaneous. Under UV light irradiation for 6 hours, the catalytic process produced a net decolorization and mineralization (50 µM MB) of about 98% and 89% respectively. Meanwhile, under visible light irradiation (10 µM MB) for 8 hours these resulted ca. 95% and 77% decolorization and mineralization, respectively. Degradation efficiency was found to be highest at basic pH (8.6). Catalyst loading of 1.0 gl-1 was found to be optimum for the degradation of 100 µM MB solution. In all conditions the UV irradiation showed much better photo-assistance than the visible light irradiation.


RSC Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 6383-6394 ◽  
Author(s):  
Haishuai Li ◽  
Linlin Cai ◽  
Xin Wang ◽  
Huixian Shi

A noval ternary nanocomposite AgCl/Ag3PO4/g-C3N4 was successfully synthesized for photocatalytic degradation of methylene blue, methylparaben and inactivation of E. coli under visible light irradiation, showing excellent photocatalytic degradation performance and stability.


2014 ◽  
Vol 29 (20) ◽  
pp. 2473-2482 ◽  
Author(s):  
Yingchang Ke ◽  
Hongxu Guo ◽  
Dongfang Wang ◽  
Jianhua Chen ◽  
Wen Weng

Abstract


2011 ◽  
Vol 335-336 ◽  
pp. 1385-1390 ◽  
Author(s):  
Shuo Wiei Zhao ◽  
Hui Xu ◽  
Hua Ming Li ◽  
Yuan Guo Xu

In order to improve the photocatalytic activity, Co was successfully loaded into Ag3VO4 by using impregnation process. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The XRD and SEM–EDS analyses revealed that Co ion was dispersed on Ag3VO4. The DRS results indicated that the absorption edge of the Co–Ag3VO4 catalyst shifted to longer wavelength. The enhanced photocatalytic activity of Co–Ag3VO4 for Methylene Blue(MB) dye degradation under visible light irradiation was due to its wider absorption edge and higher separation rate of photo-generated electron and holes. In the experimental conditions, it is demonstrated that the MB was effectively degraded by more than 95% within 40 min when the Co–Ag3VO4 catalyst was calcined at 300°C with 1 wt.% Co content.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.


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