Heterogeneous catalytic ozonation of 2, 4-dinitrophenol in aqueous solution by magnetic carbonaceous nanocomposite: catalytic activity and mechanism

2015 ◽  
Vol 57 (43) ◽  
pp. 20447-20456 ◽  
Author(s):  
Yousef Dadban Shahamat ◽  
Mahdi Sadeghi ◽  
Ali Shahryari ◽  
Niloofar Okhovat ◽  
Farshad Bahrami Asl ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Catalytic Ozonation ◽  
Heterogeneous Catalytic

Degradation of p-Chloronitrobenzene in Aqueous Solution by Iron Silicate Catalytic Ozonation

2014 ◽  
Vol 955-959 ◽  
pp. 2162-2168 ◽  
Author(s):  
Yue Liu ◽  
Lei Liu ◽  
Wei Jin Gong
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Catalytic Ozonation ◽  
Iron Silicate ◽  
Radical Scavenger ◽  
Efficient Catalyst ◽  
Green Catalyst ◽  
Hydroxyl Radical Scavenger ◽  
Radical Type ◽  
Ozonation Process

Iron silicate, a stable and efficient catalyst prepared in the laboratory has been successfully used as a catalyst combined with ozonation in the degradation of p-Chloronitrobenzene (pCNB). The catalytic ozonation removal effectiveness of pCNB was investigated under various physicochemical conditions. Both the adsorption and the single ozonation were not effective for the degradation of pCNB, but the presence of iron silicate in ozonation process could substantially enhance the pCNB removal efficiency. The hydroxyl radical scavenger experiment confirmed that iron silicate catalytic ozonation followed a radical-type mechanism. The increasing of both the iron silicate dosage and the ozone dosage could enhance the removal effectiveness of pCNB. The iron silicate catalyst could be recycled easily without decreasing any ozone catalytic activity after four successive reuses. It is concluded that the iron silicate was an efficient green catalyst for pCNB degradation in drinking water.

Fe3O4@TiO2preparation and catalytic activity in heterogeneous photocatalytic and ozonation processes

2015 ◽  
Vol 5 (2) ◽  
pp. 1143-1152 ◽  
Author(s):  
L. Ciccotti ◽  
L. A. S. do Vale ◽  
T. L. R. Hewer ◽  
R. S. Freire
Keyword(s):  
Catalytic Activity ◽  
Magnetic Nanoparticle ◽  
Catalytic Ozonation ◽  
Systematic Evaluation ◽  
Hybrid Catalyst ◽  
Heterogeneous Catalytic ◽  
Nanoparticle Preparation ◽  
Ozonation Process

Systematic evaluation of experimental variables in magnetic nanoparticle preparation and hybrid catalyst application in the heterogeneous catalytic ozonation process.

Catalytic ozonation of bisphenol A in aqueous solution using Mn-Ce/HZSM-5 as catalyst

2015 ◽  
Vol 72 (5) ◽  
pp. 696-703 ◽  
Author(s):  
Yanfang Liu ◽  
Junna Zhao ◽  
Zaixing Li ◽  
Guixia Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Bisphenol A ◽  
Heterogeneous Catalysts ◽  
Butyl Alcohol ◽  
Catalytic Ozonation ◽  
Point Of Zero Charge ◽  
Toc Removal ◽  
Tert Butyl Alcohol ◽  
Bpa Removal

Mixed manganese and cerium oxide supported on HZSM-5 were synthesized and used as heterogeneous catalysts for ozonation of bisphenol A (BPA) in aqueous solution. The prepared catalysts of Mn-Ce/HZSM-5 were characterized by X-ray diffraction, scanning electron microscopy and Fourier transform-infrared spectroscopy. The results indicated that Mn-Ce/HZSM-5 exhibits extraordinary catalytic activity for the degradation of BPA. Removal of 89.3% of BPA and 90.4% of total organic carbon (TOC) was achieved in 30 min, compared to non-catalytic ozonation, where only 50.5% BPA and 28.1% TOC removal were reached under the same conditions. Adsorption of BPA on HZSM-5 support and Mn-Ce/HZSM-5 catalysts was negligible. The strong inhibition of BPA removal by tert-butyl alcohol indicated that the attack of hydroxyl radicals was responsible for the improvement of catalytic ozonation. It was observed that at neutral pH, which is near the point of zero charge of the catalyst, the catalytic activity reached its maximum. Increasing the amount of Mn-Ce/HZSM-5 catalyst until it exceeded 3 g/L did not show a strong effect on BPA removal. The catalysts showed high stability and reusability.

scholarly journals Transition Metal Ions as Ozonation Catalysts: An Alternative Process of Heterogeneous Catalytic Ozonation

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1091
Author(s):  
Savvina Psaltou ◽  
Konstantina Sioumpoura ◽  
Efthimia Kaprara ◽  
Manassis Mitrakas ◽  
Anastasios Zouboulis
Keyword(s):  
Catalytic Activity ◽  
Metal Ions ◽  
Natural Water ◽  
Transition Metal Ions ◽  
Catalytic Ozonation ◽  
Experimental Conditions ◽  
Chlorobenzoic Acid ◽  
Heterogeneous Catalytic ◽  
Water Matrix ◽  
Phosphate Ions

The aim of this study is to elucidate the mechanism of micropollutants’ removal in drinking water by the application of catalytic ozonation, using transition metals as appropriate catalysts. For that purpose, the degradation of 500 μg/L of p-chlorobenzoic acid (p-CBA) and benzotriazole with the addition of 2 mg/L of ozone in the presence of 1 mg/L of Co(II) or Fe(II) and at pH 7.8 were examined. It was found that in distilled water experiments, both metal ions can be characterized as catalysts, enhancing the ozonation process; however, in the natural water matrix, only iron presented higher removal rates of examined organic pollutants, when compared to single ozonation. The metal ions present catalytic activity, when they can form precipitates, hence converting the initially homogeneous process of catalytic ozonation towards a heterogeneous one. However, when 2 mg/L of ozone was applied in natural water experiments, Co(II)—unlike Fe(II)—could not be oxidized into its trivalent form, hence it cannot precipitate as Co(OH)3. Therefore, under these experimental conditions, this metal was not found to present any catalytic activity. Nevertheless, the addition of phosphates (PO43−) in concentrations higher than 100 mg/L can increase the oxidation ability of the Co(II)/O3 system, due to the resulting sufficient formation of Co3(PO4)2 precipitates. Although cobalt can enhance the •OH production (and therefore, the ozonation procedure) under these conditions, the relatively highly added concentration of phosphate ions makes the treated water non-potable, resulting in the application of further treatment to remove the excess phosphates. Therefore, only Fe(II) can be considered as a sufficient catalyst to enhance the ozonation processes.

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