Ozone paper pulp bleaching

Chlorine Dioxide. Like ozone, chlorine dioxide [10049-04-4] is a powerflil oxidant. It is usually generated as used. It has been used for disinfecting drinking water and bleaching paper pulp. Its effectiveness in killing microorganisms is well documented (305,306), and it has received recent study as a gas to sterilize medical devices. It requites 50% rh or higher to be effective. Bacterial cells had a D-value of 2.6 min and spores of 24 min (307). 

Ozone is used in the food industry to inhibit growth of bacterias and mold in fruits, vegetables, and meat products. In paper and textile industries, ozone is used as a bleaching agent on wet paper pulp and cloth. 

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. 

The energehc electrons, which constitute the arc, decompose some oxygen molecules to atoms and these react with to form Oy A gas mixture with 15% ozone may be obtained. Ozone is utilized as an oxidation agent in the organic chemical industry and for the disinfection of water. Chlorine gas was earlier used for the bleaching of paper pulp, but more ecofriendly alternatives have been sought the main substitute is hydrogen peroxide H Oj, but ozone has also been tested. 

Ozone is used as an oxidizer and disinfectant for the purification of potable water supplies and in the treatment of sewage and waste water. Industrially, ozone is used in the bleaching of paper pulp, textile fibers and sugar. It is an excellent replacement for chlorine in bleaching and more reactive than either chlorine or oxygen. 

Technical, economic, and environmental advantages exist for ozone bleaching of pulp in the paper industry as an alternate to hypochlorite or chlorine bleaching which yields deleterious compounds to the environment. 

IR spectrophotometry, 661, 662 TEARS assay, 667 hydroperoxide oxidation, 692 Upid hydroperoxides, 977-8 decomposition, 669 DNA adducts, 978-84 protein adducts, 984-5 ozone adducts, 734 ozonide reduction, 726 ozonization characterization, 737, 739 peroxydisulfate reactions, 1013, 1018 Alkali metal ozonides, 735-7 Alkaline peroxide process, pulp and paper bleaching, 623... 

S Robert, JP Lamothe, and C Daneault. Treatment of thermomechanical pulp from tamarack (Larix laricinia) by ozone and ozone-peroxide bleaching process Paper mechanical properties. J. Pulp Paper Sci. 17 168-172, 1991. 

In recent years, less chlorine and more sodium hydroxide have been used for bleaching. At present, chemical pulps and the deinking of secondary fibers are the primary users of chlorine bleaching techniques. The European paper and pulp industry uses ozone, oxygen, and peroxide in place of chlorine. 

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