Mineralization of organic micropollutants (homologous alcohols and phenols) in water by vacuum-UV-oxidation (H2O-VUV) with an incoherent xenon-excimer lamp at 172 nm

Twenty different organic micropollutants (for example C1-C8 homologous alcohols and some phenols) in aqueous solution were subjected to vacuum-UV-oxidation (H2O-VUV) within a xenon-excimer flow-through photoreactor. The incoherent xenon-excimer lamp used exhibited an emission maximum at 172 nm. At this wavelength water is efficiently photolyzed with formation of hydrogen atoms and of highly oxidative hydroxyl radicals. The short lived hydroxyl radicals initiate a series of complex interrelated radical reactions that lead finally to the mineralization of the organic material dissolved in water. The efficiency of the total organic carbon (TOC) diminution is dependent on the nature of the organic substrate treated. For example, in the series of homologous alcohols the substrate methanol is mineralized faster than 1-octanol by a factor of 2.7 under identical conditions of VUV treatment and with similar initial TOC content of the water ranging between 40 and 50 ppm.