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Application of MoO3 as an efficient catalyst for wet air oxidation treatment of pharmaceutical wastewater (Experimental and DFT study)

Chen Chen, Cheng Ting, Wang Lei, Tian Yuan, Deng Qin, Shi Yisu

Archives of Environmental Protection

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2021

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Vol. 47, no. 2

47--60

EN

In this work, a highly effective catalyst (MoO3) is synthesized and applied for catalytic wet air oxidation (CWAO) treatment of pharmaceutical wastewater. The catalyst is systematically characterized to investigate the morphology, crystal structure and chemical composition, and the findings demostrated that MoO3 catalyst is successfully synthesized. The degradation mechanism is also illustrated by the density functional theory (DFT) calculation. The degradation experiments confirm that MoO3 catalyst exhibits excellent catalytic performance in CWAO, and the removal rate of TOC (Total Organic Carbon) and COD (Chemical Oxygen Demand) is achieved to more than 93%. The catalyst doses, reaction temperature and reaction time have a significant impact on the removal of pollutants. The degradation process of pollutants in CWAO could be satisfactorily fitted by the second-order kinetics. Besides, MoO3 displays a favorable stability as CWAO catalyst. DFT calculation illustrates that MoO3 catalyst is a typical indirect band gap semiconductor. Moreover, the high temperature environment provides the thermal excitation energy, which favors to the free electrons nearing Fermi level to escape the material surface, and excites them to the conduction band, then directly reduces the pollutants in CWAO. These findings demonstrate that MoO3 can be used as an efficient and excellent catalyst for CWAO of pharmaceutical wastewater.

2

Effect of the conditions of wet air oxidation of industrial wastewater on the catalyst stability

Trawczyński J.

Polish Journal of Chemical Technology

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2003

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Vol. 5, nr 4

106-108

EN

Industrial effluent (COD = 1800 mg O2/dm3) was purified by the method of catalytic wet air oxidation. Catalysts containing 0.3% wt. of Pt supported on a SiO2-TiO2 and on a carbon black composite were investigated in this process in a fixed bed reactor under T = 393 - 473 K, p = 5.0 and 8.0 Mpa, LHSV = 2 h"1. Effect of the reaction conditions on the COD decrease and catalyst's stability is discussed.

3

Effect of the conditions of wet air oxidation of industrial wastewater on the catalyst stability

Trawczyński J.

Polish Journal of Chemical Technology

|

2003

|

Vol. 5, nr 4

106-108

EN

Industrial effluent (COD = 1800 mg O2/dm3) was purified by the method of catalytic wet air oxidation. Catalysts containing 0.3% wt. of Pt supported on a SiO2-TiO2 and on a carbon black composite were investigated in this process in a fixed bed reactor under T = 393 - 473 K, p = 5.0 and 8.0 Mpa, LHSV = 2 h"1. Effect of the reaction conditions on the COD decrease and catalyst's stability is discussed.

4

Phenol wet air oxidation on platinum supported on SiO2-TiO2.

Trawczyński J., Białobok B.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

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2002

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Vol. 10, nr 57

229-234

EN

The activity of Pt/SiO2-TiO2 catalysts in the oxidation of phenol in solution wasinvestigated. The catalyst activity towards both phenol and COD conversion was determinated. The effect of process parameters on the catalytic activity was investigated; the catalyst was characterized before and after the test by BET, porosity, temp-programmed desorption (TPD) of NH3, XRD, and SEM measurements to determine the effect of the process conditions on its properties. The catalyst changed during the test because of leaching of the silica component and recrystalisation of the titania component.