Efficiency and products investigations on the ozonation of 2-methylisoborneol in drinking water.

2-Methylisobomeol (MIB) is a terpenoid produced as a secondary metabolite by some cyanobacteria and actinomycetes and thus can be present in some drinking water source waters. The removal efficiency, products, and degradation pathway of MIB in drinking water by ozonation were studied. The results showed that ozone is efficient in removing MIB from an aqueous solution, regardless of the initial MIB concentration. Hydroxyl radicals (OH) scavenger experiments indicated that hydroxyl radicals are involved in MIB degradation. The degradation products of MIB were identified by gas chromatography-mass spectrometry. Camphor was identified as a primary degradation product, which was further oxidized to form other degradation intermediates, such as aldehydes, ketones, and carboxylic acids. A possible degradation pathway for the ozonation of MIB was proposed. Qualitative and quantitative analysis of the formation of aldehydes was carried out. It was found that six aldehydes are the main aldehydes products of ozonation of MIB, namely formaldehyde, acetaldehyde, propanal, butanal, glyoxal, and methyl glyoxal.