摘要:

Studies were carried out on-site in a potable water production plant utilizing ozonation treatment at three stages of the process. The quality of water in the treatment line was studied by chemical analysis, but also for toxicity to Hela cells after XAD resin concentration, and for mutagenesis to Salmonella Ames strains and mammalian cells V79 HGPRT system. With a sufficient dose of ozone and activated carbon adsorption, the initial cytotoxicity of the raw water and the mutagenic or promoter activity are destroyed.

ISSN:0191-9512    

DOI:10.1080/01919518708552334

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Infrared absorption spectroscopy is utilized to identify and measure different nitrogen oxide species in the output of air-fed ozone generators. The concentrations of nitrous oxide (N2O) and dinitrogen pentoxide (N2O5) were determined over a wide parameter range of modern high power medium-frequency ozone generators. With a typical ozonation dose of 1 mg ozone per liter of drinking water, less than 10 ug N2O and about 20 ug N205are introduced into one liter of drinking water.

ISSN:0191-9512    

DOI:10.1080/01919518708552335

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The kinetics of the heterogeneous ozonation of o, p-activated aromatic organic compounds have been correlated with structural parameters defined by Linear Free Energy Relationships. The gross first order rate constants for these reactions were found to correlate excellently with the Hammett Polar Constant for a series of substituted phenols and pyrimidines. Strong correlation also was obtained for the kinetics of ozonation of an homologous series of 2-alkyl-4,6-dinitrophenols and the Steric Parameter. The reaction rate was observed to increase as the electron density in the ring increased and decreased with increasing size of the substituent alkyl group. A preliminary model structured around the kinetics of a gas diffusion controlled reaction with infinitely fast chemical kinetics has been proposed along with a program of research to evaluate such a model.

ISSN:0191-9512    

DOI:10.1080/01919518708552336

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

During the development of the downflow bubble column, knowledge of the specific interfacial area was a precondition for assessing the mass transfer performance. A comparison with other gas/liquid contactors shows that, in the downflow bubble column, higher mass transfer areas can be obtained than, for example, in a bottom-sparged bubble column or in a loop-type reactor in the region of high liquid throughputs. Examples for practical performance of downflow bubble columns are given, based on the derived correlations.

ISSN:0191-9512    

DOI:10.1080/01919518708552337

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Study of the ozonation of aqueous solutions of four heterocyclic nitrogen compounds, at slightly acidic pH in a heterogeneous gas-liquid system, showed that the reactivities of these compounds are different. Amitrole, a five-membered ring heterocycle, has been found to be a highly reactive compound, while atrazine, a six-membered ring heterocycle, has been found to be a poorly reactive compound. The benzotriazoles, benz-fused five-membered ring heterocycles, present intermediate reactivities. Moreovoer, the chemical natures of the ozonation by-products have been found to be different between amitrole and atrazine. With atrazine, ozone did not open the heterocyclic ring, and led to the formation of a trioxotriazine. With amitrole, ozone broke the heterocyclic ring and formed mainly formamide.

ISSN:0191-9512    

DOI:10.1080/01919518708552338

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Air or pure oxygen flowing into the discharge gap of a cold plasma reactor is the primary method for ozone production on commercial scale. The modelling of the conversion of oxygen into ozone has been set up by means of a kinetic scheme in which opposite reactions are considered. The forward reaction occurs via electronic activation, while the reverse reaction is temperature-dependent. Experimental results are in accord with this scheme, and lead to the following primary conclusions: the plasma temperature is a linear function of the applied power, while isothermal operation is the better from an economic point of view.

ISSN:0191-9512    

DOI:10.1080/01919518708552339

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The influence of polysaccharides on survival of the capsulated K54 A3 and non-capsulated K54 A3 (0) strains of Klebsiella aerogenes exposed to ozone was investigated. Because it had been shown in this work that bacteria lose approximately half of their polysaccharides when suspended in water, all bacterial assays were performed using exactly the same medium surrounding the cells, so as to create the same ozone demand. Sensitivity of both strains A3 and A3(0) to ozone as tested in the laboratory was not significantly different, although the amount of exopolysaccharides adhering to the cells were five-fold greater with A3 than with A3(0).

ISSN:0191-9512    

DOI:10.1080/01919518708552340

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Controlled, pilot-plant ozone treatment tests were conducted on twenty-nine volatile organic contaminants in distilled water and groundwater. Results show that aromatic compounds and alkenes are well removed by ozone treatment, but that alkanes are poorly removed. Also, efficiency of destruction improved for the alkenes and aromatic compounds with increasing applied ozone dosage and, for some alkanes, with increasing pH. For most compounds, the efficacy of ozone was not severely affected by the background water matrix. Generally, information gathered from the literature regarding rate constants for the ozone treatment of compounds in the gaseous phase or in organic solution predicted, to a useful degree, the effectiveness of ozone in treating aqueous solutions in the present study.

ISSN:0191-9512    

DOI:10.1080/01919518708552341

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Ozone transfer into potable water was studied in a commercial scale contactor. Ozone mass balances have been calculated to determine ozone utilization in the contactor. Gas and liquid flowrates, as well as inlet ozone concentrations in the gas were varied. From these data it was possible to determine the mass transfer coefficient, the ozone consumption and the transfer efficiency. Procedures for calculating the design of contactors and the optimal operating conditions are proposed.

ISSN:0191-9512    

DOI:10.1080/01919518708552342

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0191-9512    

DOI:10.1080/01919518708552333

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor