tailieunhanh - Ultraviolet Light in Water and Wastewater Sanitation - Chapter 4

Quá trình oxy hóa quang hóa hiệp đồng là một phát triển gần đây trong xử lý nước, liên quan đến việc loại bỏ các chất ô nhiễm có khả năng chống các phương pháp điều trị cổ điển của hơn cần thiết. Các kỹ thuật, vẫn còn phát triển hơn nữa, thường được gọi là quá trình oxy hóa thương mại tiên tiến (AOPs). Bên cạnh tính chất hóa học cụ thể liên quan đến ozone (cho một cái nhìn tổng quan, xem Hoigné [1998]), các công nghệ này liên quan đến một số khía cạnh liên quan đến. | 4 Use of Ultraviolet in Photochemical Synergistic Oxidation Processes in Water Sanitation BASIC PRINCIPLES General Photochemical synergistic oxidation processes are a recent development in water treatment related to the necessary removal of pollutants that are resistant to the more classical methods of treatment. The techniques still in further development are often termed commercially advanced oxidation processes AOPs . Besides the chemistry specifically related to ozone for an overview see Hoigné 1998 these technologies involve several aspects related to the application of ultraviolet UV Direct photolytic action on compounds dissolved in the water sources Photochemically assisted production of oxidants mainly supposed to be hydroxyl free radicals Photochemically assisted catalytic processes Although effects have been observed on the ground it must not be forgotten that an overall energetic balance is required. Considerable amounts of data have been reported in the literature related to water treatment both in laboratory experiences pilot plant investigations and fullscale applications. However even when the conditions and methods applied have been described with precision it is often not possible to formulate general guidelines for design from the positive evidence as reported. These oxidation methods are applicable for the removal of compounds resisting the more classical techniques. This effect is often considered as secondary in technical literature. More investigation on this subject is required. It certainly plays a role in combined ozone-UV processes Denis et al. 1992 Masschelein 1999 Leitzke and Friedrich 1998 . The aim of this chapter is to summarize some fundamental aspects of these applications and to tentatively indicate preliminary recommendations for future design rules and experimental protocols to be formulated and to apply. 2002 by CRC Press LLC A fundamental characteristic of UV light is that the photons of these wavelengths are of .