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.

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.

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

Research on the Treatment of Dyeing Wastewater by Heterogeneous Catalytic Ozonation Process

2011 ◽  
Vol 368-373 ◽  
pp. 3793-3796
Author(s):  
Li Ping Wang ◽  
Yong Jing Mao ◽  
Yu Chuan Guo ◽  
Er Deng Du
Keyword(s):  
High Efficiency ◽  
Removal Rate ◽  
Aeration Rate ◽  
Catalytic Ozonation ◽  
Practical Significance ◽  
Impregnation Method ◽  
Dyeing Wastewater ◽  
Heterogeneous Catalytic ◽  
Novel Catalyst ◽  
Ozonation Process

It is of great practical significance to develop integrated processes with high efficiency, adaptability and stability to treat the dyeing wastewater with the feature of high organic matter, high-color and large ranges in water quality and quantity. In this paper, a novel catalyst MnOx+FexOy/AC was prepared by the impregnation method. The catalyst was used in the heterogeneous catalytic ozonation process to treat the dyeing wastewater. The results showed that the optimal Fe:Mn ratio of catalyst is 1:2. Under the optimized conditions of pH 5, ozone aeration rate 0.2L/min, catalyst dosage 20g and the reaction time 60min, the removal rate of COD, NH3-N, TP, Chromaticity were 81.7%, 90.2%, 93.4%, 99.1%, respectively. The heterogeneous catalytic ozonation is a promising process for the treatment of dyeing wastewater.

Manganese Silicate Catalyzed Ozonation of m-Chloronitrobenzene in Drinking Water

2011 ◽  
Vol 239-242 ◽  
pp. 1159-1164
Author(s):  
Yue Liu ◽  
Zhong Lin Chen ◽  
Yu Liu ◽  
Ying Han ◽  
He Wang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Catalytic Activity ◽  
Catalytic Ozonation ◽  
Radical Scavenger ◽  
Efficient Catalyst ◽  
Green Catalyst ◽  
Manganese Silicate ◽  
Hydroxyl Radical Scavenger ◽  
Radical Type ◽  
Ozonation Process

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

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.

scholarly journals Calcite Mineral Catalyst Capable of Enhancing Micropollutant Degradation during the Ozonation Process at pH7

2020 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
Savvina Psaltou ◽  
Efthimia Kaprara ◽  
Manassis Mitrakas ◽  
Anastasios Zouboulis
Keyword(s):  
Reaction Time ◽  
Hydroxyl Radicals ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Catalytic Ozonation ◽  
Batch Mode ◽  
Heterogeneous Catalytic ◽  
Physico Chemical ◽  
Oxidative Species ◽  
Ozonation Process

Catalytic ozonation is an Advanced Oxidation Process (AOPs) based on the production of hydroxyl radicals, which are very reactive oxidative species. The aim of this study is to evaluate the catalytic activity of calcite on the ozonation of four different typical micropollutants (atrazine, benzotriazole, carbamazepine, and p-CBA) at pH 7 and for low initial concentrations (4 μΜ) by performing batch mode experiments. These compounds have different physico-chemical characteristics, as well as different rate constants, when reacting with ozone and hydroxyl radicals (•OH), being in the range of <0.15 − 3 × 105 M−1s−1 and 2.4 − 8.8 × 109 M−1s−1, respectively. It was found that most of these micropollutants can be sufficiently removed by the application of heterogeneous catalytic ozonation, using calcite as the catalyst, except for the case of atrazine, which was the compound that was most difficult to degrade, when compared to the application of single ozonation. Carbamazepine with kO3 = 3 × 105 M−1s−1 can be easily removed even by single ozonation after the first minute of the reaction time, and the addition of the catalyst eliminated the oxidation/reaction time. The application of catalytic ozonation resulted in 50% and 68.2% higher removals of benzotriazole and p-CBA, respectively, in comparison with single ozonation, even during the first 3 min of the reaction/oxidation time, due to the higher production of hydroxyl radicals, caused by the catalytic ozonation. For the case of atrazine, the addition of calcite did not enhance the micropollutant degradation, and its removal reached 83% after a 30 min application of catalytic ozonation, whereas during the single ozonation, the removal under the same reaction time was 90%.

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