(423e) Photocatalytic Degradation of Methamphetamine Using UV/TiO2

Methamphetamine (MAT) is a prescription drug and a substance of abuse; it cannot be effectively removed in wastewater treatment plants (WWTPs). As a result, MAT has been found at 61-405 ng/L in hospital effluents, WWTP influents and effluents, as well as surface waters in Taiwan. Even at trace level, MAT can pose risks of long-term exposure, bioaccumulation, and biomagnification on aquatic organisms. This project evaluates the effectiveness of eliminating MAT from waters using existent UV disinfection process in WWTPs in the presence of TiO₂ photocatalyst. We tested the use of TiO₂ (Degussa P25) under UV illumination (9 W at 365 nm) for the photocatalytic degradation of MAT to define the removal kinetics. Removal was investigated under varied experimental parameters including TiO₂ loading, MAT concentration, and pH; MAT and its intermediates throughout treatment were monitored by HPLC-MS/MS, along with TOC and IC analyses to determine the extent of mineralization. The results showed elimination of 100 ppb of MAT within 30 min of irradiation of TiO₂ at 0.03 g/L at pH 7. The degradation of MAT followed pseudo-first order kinetics conforming to the Langmuir-Hinshelwood model. Complete mineralization of 10 ppm of MAT was achieved in 180 min with 0.1 g/L of TiO₂ at pH 5, whereas the organic nitrogen was converted predominantly to NH₄⁺. Photocatalytic process with UV/TiO₂ shows promise in arresting the release of MAT and its intermediates into the water environment.