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Low-temperature stabilization of electrosynthesized tetragonal zirconia, its photoactivity toward methylene blue decolorization

Abdul Jalil, Aishah and Triwahyono, Sugeng and Sapawe, Norzahir and Ahmed, I. H. and Ab. Aziz, Muhammad Arif (2015) Low-temperature stabilization of electrosynthesized tetragonal zirconia, its photoactivity toward methylene blue decolorization. Desalition And Water Treatment, 56 (9). pp. 2402-2416. ISSN 1944-3994

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Official URL: http://dx.doi.org/10.1080/19443994.2014.960456

Abstract

Zirconia nanoparticles (ZrO2) were prepared by a simple electrochemical method and characterized using X-ray diffraction, transmission electron microscopy, Brunnauer–Emmett–Teller surface area analysis, and ultraviolet-visible diffuse reflectance spectroscopy. In this study, tetragonal ZrO2 (t-ZrO2) particles were stabilized at a lower calcination temperature without the addition of a dopant in the preparation step. It was suggested that the use of tetraethylammonium perchlorate as the supporting electrolyte was responsible for the stabilization of t-ZrO2 by preventing the agglomeration of metal clusters with undesired powders in the electrolysis system, resulting in a decrease in ZrO2 crystal size. The photoactivity of the catalyst was optimized using central composite design with response surface methodology and the optimum values of the parameters were a solution pH of 11, contact time of 4 h, catalyst dosage of 1.0 g L-1, and calcination temperature of 523 K. This resulted in 84.9% decolorization of methylene blue (MB) obtained from the predicted model, which fitted well with the laboratory results of 83.6%. The kinetics study demonstrates that the reaction followed pseudo first-order kinetics, and the rate constants KR = 0.09 mg L-1 h-1 and KLH = 0.43 L mg-1 were determined using the Langmuir–Hinshelwood model. The mineralization of MB was measured by chemical oxygen demand removal, BOD5/COD, and TOC/TOC0 ratio analyses with values of 78.5%, 1.48, and 0.21, respectively, after 4 h of contact time. The regeneration study shows that the catalyst could be maintained with a slight decrease in decolorization (<10%) after five cycling runs. Furthermore, t-ZrO2 facilitated good photoactivity towards MB decolorization under UV light in a batch reactor compared with commercial t-ZrO2 (58.7%) and Degussa P25 TiO2 (64.5%).

Item Type:Article
Uncontrolled Keywords:central composite design, electrochemical, methylene blue, photodecolorization, t-ZrO2
Subjects:A General Works
ID Code:58490
Deposited By: Haliza Zainal
Deposited On:04 Dec 2016 12:07
Last Modified:19 Apr 2017 08:56

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