Effects of Neutralization on Deodorizing Activities of Pyroligneous Liquids

Abstract

The deodorant effects of neutralized pyroligneous liquids were chemically studied to investigate their deodorant mechanisms. Three pyroligneous liquids, which were obtained from nara (Quercus serrata Thunb. and/or Quercus crispula Blume), ubamegashi (Quercus phillyraeoides A. Gray), and mosochiku (Phyllostachys pubescens Mazel), respectively, were neutralized with sodium hydroxide, and then their deodorant activities were examined. Five typical offensive odor compounds, ammonia, trimethylamine, hydrogen sulfide, methyl mercaptan, and acetaldehyde, were used in the deodorant tests. All of the neutralized pyroligneous liquids had clear deodorant effects on ammonia. Although all three of the neutralized pyroligneous liquids exhibited deodorant effects against trimethylamine, the effects of the pyroligneous liquid from ubamegashi were markedly decreased by neutralization. The deodorant effects of the three pyroligneous liquids on hydrogen sulfide were considerably increased by neutralization. The pyroligneous liquids from nara and mosochiku exhibited greater deodorant effects against methyl mercaptan after being neutralized. Finally, acetaldehyde emission was markedly inhibited by the addition of sodium hydroxide to the pyroligneous liquids.