Degradation of phenol by nanomaterial TiO2 in wastewater

The degradation of 100 mg/L phenol solution under ultraviolet (UV) in the presence of TiO2 and in the absence of it was analyzed with gas chromatography/mass spectrometry (GC–MS) and high performance liquid chromatography (HPLC). After 12 h of degradation, the products under the two conditions were both derivatized by MSTFA and TMIS, and then analyzed by GC–MS. The results show the main intermediates are the same. They are hydroquinone, resorcinol, catechol, 1,2,3-benzenetriol, (E)-2-butenedioic acid, 2-hydroxy-propaldehyde, glycerol, 3-hydroxy-propyl acid, and hydroxy-acetic acid. The chromatogram given by HPLC indicates that the presence of TiO2 is not in favor of the degradation when the concentration of phenol is 100 mg/L; its catalysis becomes evident when the concentration gets lower. Based on the intermediates, it can be proved that besides OH, H is also an important active free radical in the degradation.