Wet air and catalytic wet air oxidation of several azodyes from wastewaters: the beneficial role of catalysis

2009 ◽  
Vol 60 (8) ◽  
pp. 1989-1999 ◽  
Author(s):  
A. Rodríguez ◽  
J. García ◽  
G. Ovejero ◽  
M. Mestanza
Keyword(s):  
Azo Dyes ◽  
Oxygen Demand ◽  
Organic Carbon Content ◽  
Reactive Black 5 ◽  
Catalytic Wet Air Oxidation ◽  
Acid Orange 7 ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Acid Orange ◽  
Direct Blue

Degradation of several azo dyes, Acid Orange 7 (AO7), Acid Orange 74 (AO74), Direct Blue 71 (DB71), Reactive Black 5 (RB5) and Eriochrome Blue Black B (EBBB), well-known non-biodegradable mono, di and tri azo dyes has been studied using, wet-air oxidation (WAO) and catalytic wet air oxidation (CWAO). The efficiency of substrate decolorization and mineralization in each process has been comparatively discussed by evolution concentration, chemical oxygen demand, total organic carbon content and toxicity of dyes solutions. The most efficient method on decolorization and mineralization (TOC) was observed to be CWAO process. Mineralization efficiency with wet air and catalytic wet air oxidation essays was observed in the order of mono-azo > di-azo > tri-azo dye. Final solutions of CWAO applications after 180 min treatment can be disposed safely to environment.

scholarly journals Influence of the Active Phase (Fe, Ni, and Ni–Fe) of Mixed Oxides in CWAO of Crystal Violet

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1053 ◽  
Author(s):  
Katherine Archila ◽  
Ana María Campos ◽  
Lorena Lugo ◽  
Crispín Astolfo Celis ◽  
Sonia Moreno ◽  
...  
Keyword(s):  
Crystal Violet ◽  
Atmospheric Pressure ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Oxygen Demand ◽  
Textural Properties ◽  
Active Phase ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation

The catalytic oxidation of aqueous crystal violet (CV) solutions was investigated using Ni and Fe catalysts supported over Mg–Al oxides synthesized by the autocombustion method. The influence of temperature, loading, and selectivity were studied in the catalytic wet air oxidation (CWAO) of CV. The kind of metal had an important contribution in the redox process as significant differences were observed between Fe, Ni, and their mixtures. The catalysts with only Fe as active phase were more efficient for the oxidation of CV under normal conditions (T = 25 °C and atmospheric pressure) compared to those containing Ni, revealing the influence of the transition metal on catalytic properties. It was found that iron-containing materials displayed enhanced textural properties. The synthesis of Fe/MgAl catalysts by the autocombustion method led to solids with excellent catalytic behavior, 100% CV degradation in eight hours of reaction, 68% selectivity to CO2, and significant reduction of chemical oxygen demand (COD).

Catalytic wet air oxidation of high concentration pharmaceutical wastewater

2013 ◽  
Vol 67 (10) ◽  
pp. 2281-2286 ◽  
Author(s):  
Wei Zhan ◽  
Xiaocong Wang ◽  
Daosheng Li ◽  
Yongzheng Ren ◽  
Dongqi Liu ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Demand ◽  
Precipitation Method ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Pharmaceutical Wastewater ◽  
High Concentration ◽  
Co Precipitation

In this study, we investigated the pretreatment of a high concentration pharmaceutical wastewater by catalytic wet air oxidation (CWAO) process. Different experiments were conducted to investigate the effects of the catalyst type, operating temperature, initial system pH, and oxygen partial pressure on the oxidation of the wastewater. Results show that the catalysts prepared by the co-precipitation method have better catalytic activity compared to others. Chemical oxygen demand (COD) conversion increased with the increase in temperature from 160 to 220 °C and decreased with the increase in pH. Moreover, the effect of the oxygen partial pressure on the COD conversion was significant only during the first 20 min of the reaction. Furthermore, the biodegradability of the wastewater improved greatly after CWAO, the ratio of BOD5/COD increased less than 0.1–0.75 when treated at 220 °C (BOD: biochemical oxygen demand).

Catalytic wet air oxidation of dyeing and printing wastewater

1997 ◽  
Vol 35 (4) ◽  
pp. 311-319 ◽  
Author(s):  
L. Lei ◽  
X. Hu ◽  
H. P. Chu ◽  
G. Chen ◽  
P. L. Yue
Keyword(s):  
High Pressure ◽  
Reaction Time ◽  
Textile Industry ◽  
Porous Alumina ◽  
Supported Catalyst ◽  
Metal Salts ◽  
Treated Wastewater ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation

The treatment of dyeing and printing wastewater from the textile industry by oxidation was studied. The reaction was carried out in a two-litre high pressure reactor. In order to promote the oxidation of organic pollutants present in the wastewater, experiments were conducted using various catalysts including metal salts, metal oxides, and porous alumina supported metals. All catalysts tested were able to enhance the conversion of organic compounds in wastewater, shorten the reaction time, and lower the reaction temperature. The alumina supported catalyst has an advantage over other catalysts in that it can be easily separated from the treated wastewater by filtration and recycled. The conditions in preparing the catalyst supported by porous alumina were experimentally optimised.

Synthesis, characterization and activity of W–La/CexZr1−xO2 catalysts in the catalytic wet air oxidation of phenol

2021 ◽  
Author(s):  
Mohamed Achraf Bouabdellah ◽  
Itidel Belkadhi ◽  
Lassaad Ben Hammouda ◽  
Gwendoline Lafaye ◽  
Francisco Medina Cabello ◽  
...  
Keyword(s):  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Oxidation Of Phenol

scholarly journals Life cycle thinking case study for catalytic wet air oxidation of lignin in bamboo biomass for vanillin production

2021 ◽  
Vol 23 (4) ◽  
pp. 1847-1860
Author(s):  
Christopher S. McCallum ◽  
Wanling Wang ◽  
W. John Doran ◽  
W. Graham Forsythe ◽  
Mark D. Garrett ◽  
...  
Keyword(s):  
Life Cycle ◽  
Crude Oil ◽  
Kraft Lignin ◽  
Life Cycle Thinking ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation

A life cycle thinking analysis (LCT) conducted on the production of vanillin via bamboo wet air oxidation compared to vanillin production from crude oil or kraft lignin.

Comprehensive Evaluation of Non-Catalytic Wet Air Oxidation as a Pretreatment to Remove Pharmaceuticals from Hospital Effluents

2021 ◽  
Author(s):  
Valérie Boucher ◽  
Margot Beaudon ◽  
Pedro Ramirez ◽  
Pascal Lemoine ◽  
Kalyssa Volk ◽  
...  
Keyword(s):  
Surface Waters ◽  
Comprehensive Evaluation ◽  
Chemical Processes ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Highly Efficient ◽  
Hospital Effluents ◽  
Promising Solution

Removal of pharmaceuticals from wastewater using chemical processes is a promising solution to mitigate pollution in drinking and surface waters. Non-catalytic wet air oxidation (WAO) is a highly efficient advanced...

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