Reaction mechanisms and kinetics of chemical pretreatment of bioresistant organic molecules by wet air oxidation

Abstract Coking wastewater (CWW) is known as a highly polluting effluent. This study deals with the degradation of pollutants in terms of COD, phenol and cyanide present in CWW using catalytic wet air oxidation (CWAO) process. CWAO was carried out in batch mode using various catalysts. The investigated operating parameters are initial pH (pH i ) 3–11, temperature (T) 100–160 °C, air partial pressure (p air) 2–6 MPa, catalyst mass loading (C w ) 2–5 g/L and treatment time (t R ) of 0–6 h. Among various catalysts, the copper chloride was proved to be best for degradation of pollutants. The optimum conditions were evaluated for the degradation of organic compounds as T 130 °C, p air 8.8 MPa, C w 3 g/L and t R = 6 h. The maximum percentage reduction of COD, phenol, and cyanide was achieved through experiment at T 160 °C, p air 12.2 MPa, C w 5 g/L and t R 6 h as 97.32%, 97.94% and 99.87%, respectively. The kinetics studies were also performed to evaluate the rate constant (k), and reaction order with respect to COD, phenol, CN, CW and p air.

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Kinetics of Wet Air Oxidation of High-Strength Industrial Wastewater

Journal of Environmental Engineering ◽

10.1061/(asce)0733-9372(1997)123:9(852) ◽

1997 ◽

Vol 123 (9) ◽

pp. 852-858 ◽

Cited By ~ 12

Author(s):

Sheng H. Lin ◽

Shin J. Ho

Keyword(s):

Industrial Wastewater ◽

High Strength ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Kinetics Of

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Reaction mechanisms and kinetics of chemical pretreatment of bioresistant organic molecules by wet air oxidation

Water Science & Technology ◽

10.2166/wst.1997.0100 ◽

1997 ◽

Vol 35 (4) ◽

pp. 119-127 ◽

Cited By ~ 5

Author(s):

D. Mantzavinos ◽

R. Hellenbrand ◽

A. G. Livingston ◽

I. S. Metcalfe

Keyword(s):

Organic Pollutants ◽

Reaction Mechanisms ◽

Noble Metals ◽

Heterogeneous Catalysts ◽

Operating Conditions ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Total Oxidation ◽

Analytical Technique ◽

The Impact

The partial wet air oxidation of aqueous solutions of p-coumaric acid and polyethylene glycol, two model organic pollutants typically found in wastewaters of agricultural origin and polymer-manufacturing respectively, has been investigated at temperatures from 373 K to 513 K and oxygen partial pressures from 0.2 MPa to 3 MPa. Reaction intermediates have been identified and their concentration profiles have been determined using liquid chromatography as the main analytical technique, and reaction mechanisms and pathways have been postulated. The impact of various heterogeneous catalysts, such as metal oxides and noble metals, on the kinetics and mechanisms of the reaction has also been studied. Conversion of these model compounds through various oxidation intermediates to end-products, such as carboxylic acids, could be easily achieved even under mild operating conditions, while further total oxidation proved to be difficult even under more severe conditions. Catalysts were found to be, in general, capable of increasing the rates of both partial and total uncatalysed oxidation. The stability of some of the catalysts used has also been studied with respect to metal leaching and deactivation. The implications for complete removal of bioresistant organic pollutants by partial wet oxidation followed by a biological treatment step are also discussed.

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Studying the Phenol Degradation in Synthetic Wastewater by Catalytic Wet Air Oxidation Process in Batch Reactor

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.20.27827 ◽

2018 ◽

Vol 7 (4.20) ◽

pp. 629

Author(s):

Ghayda Yaseen AL Kindi ◽

Faris Hammoodi AL Ani

Keyword(s):

Batch Reactor ◽

Phenol Degradation ◽

Pillared Clay ◽

Synthetic Wastewater ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Operation Condition ◽

Optimum Proportion ◽

Catalytic Kinetics ◽

Kinetics Of

The current paper studies the viability of using a Batch reactor, by five types of Al-Fe pillared clay that prepared from five regions in Iraq for phenol degradation in synthetic wastewater. The operation condition study through variables in (pH, pressure, temperature, pillared load, phenol load). The findings have illustrated that phenol degradation could be increase via incrementing temperature, pressure, pillared load and degrease in phenol load. Phenol good degradation proportion which was 97 %, has been achieved at optimum proportion (pH= 3.9, temperature = 150 °C, pressure = 3.5 MPa, in addition to phenol concentration = 500 mg/l). The two models power-law and Langmuir−Hinshelwood have been used to study the catalytic kinetics of the phenol degradation. From results shown the activation energy for every response equivalent to (37114.014 j/mol) for Anbar (37795, 48783.9, 36628, 40785 j/mol) for Erbil, Mosul, Baghdad and Basra respectively. It was proved that the reaction in this study is under kinetics control.

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