Synergistic effect and interaction of nano zero-valent iron and Al13 in carbamazepine removal

In this study, a multi-functional coagulant with both coagulation and oxidation function was obtained by pre-doped nano zero-valent iron (nZVI) with Al 13 for the removal of the typical emerging contaminants Carbamazepine (CBZ). At the optimal doped dosage of nZVI, the pre-doped agent (Al 13 @nZVI) showed 23% improvement of the maximum removal rate of Carbamazepine compared with Al 13 under pH 7. It was found that Al 13 @nZVI could produce H 2 O 2 in situ at pH 2 to pH 8, especially under acid conditions. By the analysis of FT-IR, it could be found that the groups of C-N, benzene, and C O were disappeared after treatment. Instead, -NO 2 was found in treated water which indicated the breakage and oxidation of amine group. Thus, the effects of pH on Al 13 and Al 13 @nZVI were different. Al 13 will undergo depolymerization and decompose into small polymers with low positive charge density with the increasing of pH, while, because of Al 13 @nZVI having oxidation ability, effect of pH on Al 13 @nZVI was not that significant. The influence of Humic acid (HA) with different concentration on CBZ removal were analyzed. The system with 2 mg/L HA showed better removal performance of both CBZ and total dissolved organic carbon (DOC) compared to the system with 1 mg/L HA, which may because of the increase of the necessary nuclei for the flocs formation, as well as the bridging function by the long chain structure of HA. Moreover, Al 13 @nZVI was found improved the removal efficiency of organic matters with molecular weight about 1500–2000 Da compared to Al 13 .