Abstract
The effect of wavelength on the photochemical decomposition of dodecylbenzenesulfonate (LAS) and the decomposition process were investigated. When LAS in water was subjected to monochromatic irradiation between 200 and 700 nm from a spectroirradiator equipped with a Xe arc lamp, the largest decomposition rate was observed at 215 nm. Thus a low-pressure mercury lamp providing radiation mainly in the lower ultraviolet (UV) range was chosen as a light source for the photochemical reaction. LAS in various kinds of water samples, e.g., city sewage, treated sewage water, river water, sea water and others, was found to be rapidly decomposed by irradiation with the light source and there was little difference among water samples. Since formaldehyde and formic acid were identified among the photochemically decomposed products of LAS, it is suggested that LAS is photochemically decomposed through formaldehyde and formic acid.
