PHYSICAL-CHEMICAL MECHANISMS OF THE REACTION OF OZONE WITH AQUATIC HUMIC SUBSTANCES

The purpose of this investigation is to assess the nature of the interactions of ozone with aquatic humic materials. Specifically, the validity and use of ozone in water treatment for humics removal, definition of concepts and terms used in ozonation practice, control of the process, the importance of mass transfer, and the chemical properties of the humics were investigated.;The results indicate that classical rate laws could be used to describe the reactions. All the reactions could be separated into three mechanisms: slow, reaction rate limited; slow mass transfer limited;, and fast mass transfer limited. The importance of ozone decomposition, presence of inhibitors, and voltilization was also demonstrated. Rate curves were used to differentiate between oxidative coupling and degradative mechanisms. The information derived was utilized as input to a protocol for design of water treatment facilities utilizing ozone for organics control. The conditions of ozonation were defined such that control over the process and reproducibility of results could be ensured.;The major avenue of approach was to follow changes in different parameters as a function of time of ozonation in a heterogeneous reaction matrix. These includes non-specific measurements of substrate concentration such as ultraviolet absorbance, dissolved organic carbon, and particle size; products of ozonation such as carbonyl compounds and phenolics, and ozone concentration. Reactions were conducted with natural humics, analogs and model compounds. These included soil humic acid, soil fulvic acid, lignosulfonic acid, and several low molecular weight phenolic type compounds.