RESUMEN
17ß-Estradiol (17ß-E2) as a non-conventional pollutant with high damage, the effective removal of 17ß-E2 had been studied wildly. In recent years, nano materials application enabled the rapid removal of 17ß-E2. Nano zero valent iron (nZVI) as one of the most widely used nano materials could also be used to degrade 17ß-E2. But, the degradation performance of nZVI was limited by oxidation and aggregation. Therefore, this study explored the degradation mechanisms of 17ß-E2 by nZVI and the enhancement mechanisms of nZVI by citrate. Firstly, 17ß-E2 could be effectively degraded under acidic conditions without the addition of citrate. Citrate had protective effect on nZVI, so the degradation efficiency in neutral condition and degradation rate at all pH values of 17ß-E2 were enhanced greatly in nZVI-citrate system. 17ß-E2 degradation was mainly about group change and cleavage of ring A, as well as dominated by O2-⪠and OHâ in the absence and presence of citrate. The formation of dimers and trimers proved the existence of laccase-like reaction during the 17ß-E2 degradation process by nZVI. In nZVI-citrate system, the laccase-like reaction was replaced by specific cross-coupling of 17ß-E2, E1, and citrate. Overall, the study proved that citrate could enhance the degradation of 17ß-E2 by nZVI.
