Ozone surface decontamination

The attraction between the air bubble and contaminants is believed to be primarily a result of particle surface charges and bubble size distribution. The more uniform the distribution of water and microbubbles, the shallower the flotation chamber can be. Generally, the depth of effective flotation chambers is between 0.9 and 2.7 m (3 and 9 ft). Flotation units can be round, square, or rectangular. Gases other than air can be used. The petroleum industry has used nitrogen, with closed vessels, to reduce the possibilities of fire. Ozone can be fed through with air for more efficient reduction of soluble iron, VOCs, and so on.57 Ozone-UV flotation is another alternative for groundwater decontamination. 

Bennett etal. have presented a model for gaseous pollution sorption by plants. The model includes all the known factors that might have a significant effect on pollution sorption by plant leaves, including gas concentration (ambient air and internal leaf), gas fluxes (external and internal), resistance to flow (leaf boundary layer, stomatal, and internal), nature of leaf surfaces (stomatal presence, cutin, and surface properties), importance of gas solubility and thus solute concentration within the leaf, and ability of the plant to metabolize pollutants (decontaminate itself). They mentioned the reactivity of ozone as another factor to consider. They believe that surface sorption may be important, at least over short periods. They presented a possible mathematical representation of these factors, which they suggested is equivalent to the mathematical statement of Ohm s law. This material is well int ated in the review by Bennett and Hill. ... 

This entry introduces applications of ozone technology in various areas water and wastewater treatment control of the microbial safety of food decontamination of soils polymer surface modification and bleaching paper pulps. For water and wastewater treatment, in addition to being used alone, ozone is increasingly used in combination with heterogenous catalysts, UV/H2O2 (advanced oxidation process), and biological treatment to enhance ozonation efficiency. The discussion that follows mainly introduces the applications of ozone in water and wastewater treatment because ozone has been both extensively and intensively used in this area however, it does briefly describe other applications. 

Ozone has been applied successfully and extensively for water and wastewater treatment. Ozone also has been used as a safe and effective antimicrobial agent in many food applications. Other applications of ozone include soil decontamination, polymer surface modification, and bleaching paper pulps. It is recognized that for water treatment, the combined use of ozone with either biological treatment, or heterogenous catalysts, or UV and/or H2O2 makes the whole process more efficient. 

Their use has, however, an important drawback that is related to the rather low surface areas and not easy preparation methods. But the recent achievements in the synthesis of metal-modified mesoporous silicas and development of new methods for the synthesis of oxides with higher surface areas diversified the number of catalysts and applications of mixed oxides as catalysts in liquid-phase oxidations. The performances recently reported opened new perspectives for the green and sustainable oxidation using such materials and extended the interest for the application of these reactions in industrial organic synthesis and water decontamination. Furthermore, coupling the photooxidation with Fenton and ozonation processes provides extremely attractive techniques in advanced oxidation processes for eliminating organic contaminants in wastewaters. 

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