摘要:

A method for the assessment of the optimal operating conditions for a mechanically stirred gas–liquid reactor is presented. The method exploits both fluid dynamic and chemical information. First, the behavior of the specific stirring power as a function of the stirrer speed allows singling out the dispersion region, in which the most efficient gas–liquid mass transfer is achieved. Inside this region, the analysis of experimental data obtained when considering a chemical system reacting at moderate Hatta numbers (i.e., Ha < about 2) allows determination of the rate constants and the fluid dynamic parameters (i.e., the mass transfer coefficient in the absence of chemical reaction and the characteristic diffusion time).

ISSN:0191-9512    

DOI:10.1080/01919519408552497

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Pilot-plant studies were conducted in two source waters to determine the effects of predisinfection with ozone alone and with a combination of hydrogen peroxide and ozone (PEROXONE) on the production of assimilable organic carbon (AOC) compounds. Colorado River water (CRW) and State project water (SPW) from Northern California were treated with ozone alone at applied dosages ranging from 1 to 4 mg/L and with PEROXONE at hydrogen peroxide/ozone (H2O2/O3) ratios of 0.05, 0.10, 0.20, and 0.30. Ozonation of CRW with applied dosages of 1.0,2.0, and 4.0 mg/L increased AOC concentrations from 70μg C/L to 275, 350, and 224 μg C/L, respectively. Ozonation of SPW with an applied dosage of 4.0 mg/L elevated AOC concentrations from 70 to 522μg C/L.

ISSN:0191-9512    

DOI:10.1080/01919519408552498

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The degradation of the herbicide cyanazine in aqueous solution by ozone and UV radiation separately have been developed. In the ozonation process, the influence of the operating variables is observed, the stotchiometric ratio for the reaction is obtained, and a free radical reaction mechanism is proposed. The kinetic study establishes that the process is controlled by the chemical reaction, which takes place in the very slow kinetic regime. The reaction rate constants are determined as a function of temperature and pH.

ISSN:0191-9512    

DOI:10.1080/01919519408552499

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The decomposition of 2,4-dichlorophenoxyacetic acid in aqueous solutions has bsen studied using ozone and ultraviolet radiation at different pH, ozone production, and initial concentration of pesticide. A mathematical model which incorporates the rate of mass transfer of ozone, the oxidation kinetics of 2,4-D and the kinetics of formation and oxidation of the intermediates was used. A global rate constant was calculated and an empirical equation which correlated that constant with ozone production, initial concentration of 2,4-D and pH at the same temperature was determined.

ISSN:0191-9512    

DOI:10.1080/01919519408552500

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The post-ozone plant at Wiggins waterworks was commissioned during 1984. The main objective of the post–ozone plant was to ensure proper disinfection, including the elimination of viruses, whenever raw water for the works was pumped from the polluted lower Umgeni River. The main problems experienced with the post–ozone plant were poor ozone transfer efficiency in the contact tank and poisoning of the catalyst in the thermal-catalytic destructor.

ISSN:0191-9512    

DOI:10.1080/01919519408552501

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A major component in the disinfection cost of mine water is the oxidation of microbiologically formed nitrite ion, which can be effectively oxidized by ozone (at close to the stoichiometric ratio of 3.4 mg O3per mg nitrite–snitrogen. The injudicious use of oxidizing disinfectants in the mine water may be implicated n i nitrite ion buildup. Laboratory batch reactor experiments show that 3 to 12 mg Cl2/L and 3 to 11 mg CIO2/L can inhibit nitrite ion oxidation byNitrobacter. This inhibitive effect has not been observed for ozone.

ISSN:0191-9512    

DOI:10.1080/01919519408552502

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919519408552496

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor