THE FATE OF ARSENIC IN A LAMINAR DIFFUSION FLAME

An arsenic compound (cacodylic acid) has been added to laminar diffusi on flames burning in a co-flowing stream of air. Two fuels were used v iz. ethene (C2H4) and a mixture of hydrogen and nitrogen. Samples of a erosols and gaseous species were collected within the flames and above the flames with filters and sorbent tubes. The hydrogen flame showed the conversion of arsenite to arsenate with increased residence time t hrough the flame. The conversion of arsenite to arsenate in the ethene flames was inhibited by the emission of soot, which apparently compet ed with the arsenic for oxygen in the postflame gas. Arsenic was not f ound to be incorporated into soot particles. The carbon and arsenic we re present in the postflame gases as two distinct aerosol phases. The addition of arsenic did not have a significant effect on the formation and oxidation of soot. The addition of arsenic did not lead to the pr oduction of organoarsenic species; only common polycyclic aromatics we re found in the sooting flames.