Decomposition of volatile fatty acids using electron beam irradiation

Abstract

Volatile fatty acids (VFAs) are representative odorous compounds. This study was carried out to decompose VFAs using electron beam irradiation. Acetic acid, propionic acid, butyric acid, isovaleric acid, and valeric acid were used as target VFAs. In order to confirm the decomposition efficiency and characteristics by various influential factors, experiments on the absorbed dose, background gas, and initial concentration were performed. The results confirmed that the removal efficiency increased with an increase of the absorbed dose. In addition, the removal efficiency was increased with an increase of the molecular weight of these compounds (in the following order: acetic acid < propionic acid < butyric acid < isovaleric acid < valeric acid). The removal efficiencies of all target VFAs were highest when used with O2 as a background gas. We found the lowest removal efficiency at the He atmosphere. The results of by-product analysis confirmed that valeric acid was decomposed into butyric acid and propionic acid, and then decomposed into acetic acid. That is, high molecular weight acids would be decomposed into low molecular weight acids by electron beam irradiation.