Liquid-phase non-thermal plasma-prepared N-doped TiO2 for azo dye degradation with the catalyst separation system by ceramic membranes

2010 ◽  
Vol 62 (5) ◽  
pp. 1060-1066 ◽  
Author(s):  
Hsu-Hui Cheng ◽  
Shiao-Shing Chen ◽  
Yi-Wen Cheng ◽  
Wei-Lun Tseng ◽  
Yi-Hui Wang

This study strived to improve the photocatalytic activity by using liquid-phase non-thermal plasma (LPNTP) technology for preparing N-doping TiO2 as well as to separate/recover the N-dope TiO2 particles by using ceramic ultrafiltration membrane process. The yellow color N-doped TiO2 photocatalysts, obtained through the LPNTP process, were characterized with UV–Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysis (ESCA). The UV–Vis spectrum of N-doped TiO2 showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectra showed that the peak positions and the crystal structure remained unchanged as anatase after plasma-treating at 13.5 W for 40 min. The photocatalytic activity of N-doped TiO2 was evaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours in a continuous-flow photocatalytic system. For membrane separation/recover system, the recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min, and the result indicated that the photocatalyst was able to be separated/recovered completely.

2021 ◽  
Vol 45 (1) ◽  
pp. 383-393
Author(s):  
Mohammad Razaul Karim ◽  
Mohammed M. Rahman ◽  
Abdullah M. Asiri

A reduced graphene oxide–diaminobutane (rGO–DAB) organic hybrid revealed excellent N doping, flexible interlayer distance, and light-harvesting property to support optimized photocatalytic activity for water splitting and dye degradation.


2012 ◽  
Vol 455-456 ◽  
pp. 110-114 ◽  
Author(s):  
Xuan Dong Li ◽  
Xi Jiang Han ◽  
Wen Ying Wang ◽  
Xiao Hong Liu ◽  
Yan Wang ◽  
...  

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.


2018 ◽  
Vol 779 ◽  
pp. 97-101 ◽  
Author(s):  
Shynggys Sadyk ◽  
Timur Sh. Atabaev

In this study, a facile method was used to prepare ZnO tetrapods for potential dye degradation applications. Field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX) and UV-Vis spectroscopy were employed to investigate the morphology, chemical composition, and photocatalytic properties of prepared ZnO tetrapods. A Rhodamine B (RB) dye was used as a model dye to study the photocatalytic activity of the prepared sample. It was shown that RB dye can be efficiently degraded in the presence of ZnO tetrapods under continuous UV-light illumination. Thus, prepared ZnO tetrapods with excellent photocatalytic properties can be potentially used in wastewater treatment.


Author(s):  
Radhika R Nair ◽  
Mothi Krishna Mohan ◽  
Sunaja Devi

La3+ doped TiO2 photocatalysts were successfully synthesized by combustion method in the presence of urea and were characterized by various physico-chemical techniques. Further, the photocatalytic performance of the synthesized catalysts was monitored by photocatalytic degradation of synthetic cationic dye-Methylene Blue (MB) under solar illumination. The bicrystalline phase of anatase and rutile was confirmed by X-ray diffraction analysis. Moreover, the transformation from anatase to rutile phase proceeds at a slower rate in the La3+ doped TiO2 catalysts. Effective separation of charge carriers, a synergistic effect in the bicrystalline framework of anatase and rutile, smaller crystallite size, and higher concentration of surface adsorbed hydroxyl groups helped these catalysts to show improved activity for the dye degradation. Copyright © 2018 BCREC Group. All rights reservedReceived: 28th July 2017; Revised: 19th October 2017; Accepted: 30th October 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Nair, R.R., Mohan, M.K., Sunajadevi, K.R. (2018). Enhanced Photocatalytic Activity of La3+ doped Bicrystalline Titania Prepared via Combustion method for the Degradation of Cationic dye Under Solar Illumination. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 119-126 (doi:10.9767/bcrec.13.1.1427.119-126) 


Author(s):  
Jutarat Kwakkaew ◽  
Matthana Khangkhamano ◽  
Rungrote Kokoo ◽  
Weerachai Sangchay

TiO2-based nanomaterials have been extensively synthesized and used in a wide range of photocatalytic applications. The photocatalytic oxidation process, however, is only activated by irradiation with ultraviolet (UV) light which limits its indoor applications. Herein, to improve such limitations, N/Li2MoO4-doped TiO2 nanoparticles were prepared via sol-gel method. Li2MoO4 concentration was varied. The catalysts were characterized by XRD, XPS, FE-SEM, and UV-Vis spectroscopy. As-synthesized N/Li2MoO4-doped TiO2 catalysts exhibited their crystal sizes of as fine as 20 nm in diameter whereas that of the pure TiO2 was about 35 nm. The absorption ranges of the N/ Li2MoO4-doped catalysts were relocated from UV region toward visible light region. The catalyst with 1 mol% Li2MoO4 offered the highest degradation rate of methylene blue (MB) solution upon visible light irradiation. Its fine crystal size, narrow band gap energy (2.82 eV), high defect concentration, and strong light absorption in visible region are responsible for the enhanced photocatalytic activity of the 1 mol% Li2MoO4.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3105
Author(s):  
Antonietta Mancuso ◽  
Olga Sacco ◽  
Vincenzo Vaiano ◽  
Barbara Bonelli ◽  
Serena Esposito ◽  
...  

Fe-doped titania photocatalysts (with 1, 2.5, and 3.5 wt. % Fe nominal content), showing photocatalytic activity under visible light, were prepared by a soft-template assisted sol–gel approach in the presence of the triblock copolymer Pluronic P123. An undoped TiO2 photocatalyst was also prepared for comparison. The photocatalysts were characterized by means of X-ray powder Diffraction (XRPD), Quantitative Phase Analysis as obtained by Rietveld refinement, Diffuse Reflectance (DR) UV−Vis spectroscopy, N2 adsorption/desorption at −196 °C, electrophoretic mobility in water (ζ-potential), and X-ray photoelectron spectroscopy (XPS). The physico-chemical characterization showed that all the samples were 100% anatase phase and that iron was present both in the bulk and at the surface of the Fe-doped TiO2. Indeed, the band gap energy (Eg) decreases with the Fe content, with Tauc’s plot determined values ranging from 3.35 (undoped TiO2) to 2.70 eV (3.5 wt. % Fe). Notwithstanding the obtained Eg values, the photocatalytic activity results under visible light highlighted that the optimal Fe content was equal to 2.5 wt. % (Tauc’s plot determined Eg = 2.74 eV). With the optimized photocatalyst and in selected operating conditions, under visible light it was possible to achieve 90% AO7 discoloration together with a TOC removal of 40% after 180 min. The kinetic behavior of the photocatalyst was also analyzed. Moreover, the tests in the presence of three different scavengers revealed that the main reactive species are (positive) holes and superoxide species. Finally, the optimized photocatalyst was also able to degrade phenol under visible light.


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