Effect of pollutant gases on chlorophyll a multilayer

Abstract

The pollutants were CO, CO2, SO2, H2S, NO, and NO2. Electronic and IR spectroscopies were used to monitor the time effect of the polluting gases on chlorophyll a (chl a) molecules. TLC, atomic absorption and electronic spectroscopies were used to characterize the reaction products. Neither CO nor CO2 affect the chl a molecules in the multilayer arrays. Upon exposure to SO2, many modifications on the electronic and IR spectra were observed. One of the reaction products is pheophytin a. A mechanism is presented to explain the reaction of SO2 with chl a. The effect of H2S on chl a is less pronounced than that of SO2, but the end products are the same. NO and NO2 have exactly the same effect on the chl a multilayer. The reaction is much more drastic than the reaction of chl a while either SO2 or H2S. There is opening of the cycle and nitration of the chl a molecule.