Comparison of UV/H2O2 and UV/PS processes for the degradation of thiamphenicol in aqueous solution

Thiamphenicol (TAP) has been widely used in aquaculture to prevent bacterial diseases. However, this drug exhibits toxic side effects on the haemopoietic system. The removal of residual TAP in wastewater in advanced oxidation processes (AOPs) was rarely reported before. In this study, degradation of TAP in aqueous solution by UV alone, UV/H2O2 and UV/PS processes was investigated. The results showed that UV/H2O2 and UV/PS significantly enhanced the degradation compared to UV alone. The TAP degradation followed a pseudo-first-order kinetics pattern well. The k(obs) declined with the increase of the initial TAP concentration, and increased with increasing oxidant dosage. The TAP degradation with UV/H2O2 process was favorable under neutral and acidic conditions, and with UV/PS process was favorable under acidic and alkaline conditions. HCO3- markedly inhibited the degradation with the both processes, NO3- had a slight inhibition on the degradation in UV/H2O2 system, and Cl- significantly enhanced the degradation with UV/PS process. HA markedly inhibited the degradation with the both processes. SO4-center dot played the main role in the TAP degradation by UV/PS process. When TAP was completely degraded, only part of TAP was mineralized with UV/H2O2 process, and was totally mineralized with UV/PS process. The possible degradation pathways were proposed based on the intermediate products obtained by LC-TOF-MS analysis. The electrical energy per order (EE/O) analysis showed that UV/PS process was a less energy consumption process. The results from this study revealed that UV/PS process was a cost-effective process in the degradation of TAP. (C) 2017 Elsevier B.V. All rights reserved.