LASER DEGRADATION OF POLLUTANTS - POLYCHLOROBIPHENYLS, TRIAZINES AND POLYCYCLIC AROMATIC-HYDROCARBONS

Visible and UV radiations have been widely used to induce chemical rea ctions in gases, liquids and heterogeneous systems before the developm ent of commercial lasers for use in these regions. The availability of laser sources has allowed extensive studies on chemical reactions and time-resolved techniques to investigate the mechanism of excitation a nd relaxation of organic molecules in gaseous and condensed phases. A very important field recently investigated is the laser-induced decomp osition of organic molecules, present either as ps or as major constit uents of or traces in solutions, with the aim of removing toxic specie s from chemically hazardous wastes. An investigation of laser-induced decomposition of important categories of pollutants such as polychloro biphenyls, herbicides (triazines) and polycyclic aromatic hydrocarbons will be reported here. The experiments demonstrate the effectiveness of laser-induced techniques for the decomposition of these compounds. In most cases photofragmentation leads to the formation of non-toxic p roducts in very high yields.