Research on the structure and reactivity of soot (black carbon) continues. Although topics related to the role of the solid phase and studies of carbonaceous atmospheric particulate are receiving attention, the emphasis of the work continues to be on heterogeneous photochemical reactions involving soot and reaction schemes in more complex systems. The photochemical behavior of reaction systems involving soot being studied under conditions of simulated solar radiation include: (i) soot/sulfur dioxide/oxygen/water vapor The role of the surface, through selected surface reaction and incorporation of trace metal constituents, is included in this study. (ii) soot/oxides of nitrogen (iii) soot/ozone The kinetics and mechanisms of the latter two reaction systems, previously determined in this laboratory, provide a solid basis for this group of studies. Several surface-sensitive vibrational and ultraviolet spectroscopies are employed as analytical tools in this work. Reactions of soot are being studied in more complex systems than previously. Specific focus currently is on the effect of certain reactions on the subsequent catalytic activity and reactivity of soot, and the determination of kinetics and mechanisms of soot reactions in multireactant systems. Investigations of both the photochemical reactions and multireactant system are being carried out at low concentration levels in a specially-designed, optical path, reaction cell interfaced simultaneously with an a fourier transform - infrared spectrometer and Cahn electrobalance.
