{Reference Type}: Journal Article
{Title}: Insights into the accelerated venlafaxine degradation by cysteine-assisted Fe2+/persulfate: Key influencing factors, mechanisms and transformation pathways with DFT study.
{Author}: Huang W;Fu B;Fang S;Wang F;Shao Q;Du W;Fang F;Feng Q;Cao J;Luo J;
{Journal}: Sci Total Environ
{Volume}: 793
{Issue}: 0
{Year}: Nov 2021 1
{Factor}: 10.753
{DOI}: 10.1016/j.scitotenv.2021.148555
{Abstract}: The effective removal of refractory antidepressant in wastewater is challenging. In this study, a novel strategy of cysteine-assisted Fe2+/persulfate system (Fe2+/Cys/PS) was applied for the venlafaxine (Ven, as a typical antidepressant) degradation. The obtained results revealed that the Ven removal was evidently accelerated and enhanced in Fe2+/Cys/PS process, and achieved complete degradation in 5 min with optimal dosage. Further analysis indicated that the Ven degradation efficiency was associated with the chemical concentrations (i.e. Fe2+, Cys and PS) and operational conditions (i.e. pH and temperature). Moreover, the reactions were not impacted by the co-occurring organic matters (i.e. fulvic acid) and inorganic ions (i.e. Cl-) potentially existing in real wastewater matrices. Mechanistic explorations demonstrated that the presence of Cys promoted the Fe3+/Fe2+ redox cycle, and thus enhanced the reactive oxygen species yields (ROS). The OH was considered as the primary ROS in Fe2+/Cys/PS process for Ven degradation via the radical scavenger verification. Also, the main intermediates of Ven degradation were identified, and the possible transformation pathway was proposed, in which the hydroxylation attacked by the OH was the main reaction. Moreover, the active reaction sites in Ven were calculated with the density function theory (DFT), which was consistent with the observed metabolic routes.