ISSN:0191-9512    

DOI:10.1080/01919519809480352

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The objective of this study was to examine the reaction between ozone and p-hydroxybenzoic acid, in view of kinetic regime and by-product formation. It was found that the highest specific reduction efficiency of p-hydroxybenzoic acid, THMFP and HAAFP occurred within the kinetic regime of slow reaction, other than the very slow reaction regime. Besides, the efficient way to decrease the glyoxal formation, the ozonation by-product, is to control the reaction duration before the ozonation time of peak glyoxal, which fell within the slow reaction kinetic regime as well.

ISSN:0191-9512    

DOI:10.1080/01919519809480347

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Ozone decay kinetics in various natural waters and their impact on modeling dissolved ozone concentration profiles in a bubble column contactor were studied. The results demonstrated that the commonly-used first-order kinetics with a constant rate constant were unable to describe the ozone decay behavior, particularly in cases where the initial ozone demand was significant. An explanation is that the water's reactivity toward ozone changes substantially as the ozonation depletes those readily reactive compounds. As a result, an exponentially decreasing function was proposed to provide better estimates of the ozone decay curves.

ISSN:0191-9512    

DOI:10.1080/01919519809480348

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This study is related to the ozonation of free and combined amino acids, which present a high reactivity with ozone. Amino acids reactivities studied in the presence or absence of tert-butyl alcohol as radical scavenger were found to be related to their structures. Amino acid side chains seem to be the main sites that are responsible for the high ozone reactivity in polypeptide structures. Ozonation of amino acids led to the formation of aldehydes such as formaldehyde, acetaldehyde, glyoxal and glyoxal derivatives. The direct ozone reaction has been shown to favor aldehyde production.

ISSN:0191-9512    

DOI:10.1080/01919519809480349

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Danckwerts and film theories have been compared through the aqueous ozonation kinetic study of three organics: crotonic, cinnamic and 0hydroxycinnamic acids. At the conditions investigated, these compounds areremoved from water exclusively by direct reactions with ozone and the kinetic regime of ozone absorption corresponds to a fast second order irreversiblereaction. In this regime, Danckwerts theory provides wider possibilities than film theory for the determination of the rate constant and individual liquid side masstransfer coefficients. The ozonation reactor was operated as an agitated cell to determine the rate constant and as an agitated tank to obtain the mass transfercoefficient. Rate constants were found to increase with increasing pH. AtpH 7 the ozone reactivity of these compounds was in the following increasing order:Cinnamic acid <⃒ crotonic acid <⃒ o‐hydroxycinnamic acid. AtpH 3 differences in reactivity were not significant.

ISSN:0191-9512    

DOI:10.1080/10874506.01919512.1998

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The light power of a xenon excimer VUV source was determined by means of oxygen actinometiy. It was found that the method is notapplicable for direct measurement of the light power mainly because of the side-reactions of ozone with oxygen atoms. Model calculations led to a simple equation between the quantum yield and the concentrations of ozone and oxygen. The correlation between the overall quantum yield and the ozone and oxygen concentration at room temperature is Φ = 2 - 1.l0[O3]/(O2]1.94, and at atmospheric oxygen pressure Φ = 2 - 520 [O3].

ISSN:0191-9512    

DOI:10.1080/01919519809480350

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor