Solar Mineralization of Hard-Degradable Amphetamine Using TiO2/RGO Nanocomposite

Illicit drugs have attracted much extensive scientific interest as a class of environmental contaminants due to their frequent occurrence, hard degradability, and potential risk to aquatic life and human. In this work, TiO2/reduced graphene oxide (RGO) nanocomposites were used to degrade amphetamine under solar light. Among the prepared photocatalysts, nanocomposite with 30 mg RGO (TiO2/RGO30) possessed the best photocatalytic activity in the photodegradation of hard-degradable amphetamine under solar light irradiation. The mineralization efficiency of 91% were achieved after 180 min solar light irradiation. The enhanced photocatalytic degradation of TiO2/RGO30 nanocomposite could be attributed to the increased optical absorption, effective separation, and migration of photogenerated charge carriers as the results of introducing RGO in the nanostructure. Several intermediates were identified during the degradation process using liquid chromatography tandem mass spectrometry (HPLC/MS-MS) technique. Based on the identified intermediates, the repeated hydroxylation of the amphetamine and its fragmentation are proposed for the degradation pathway.