Construction of highly dispersed NH2-MIL-101(Fe)/g-C3N4 heterostructure with excellent photocatalytic redox capability

Through a facile oil bath method, a novel highly dispersed NH2-MIL-101(Fe)/carboxylated g-C3N4 (NM-101(Fe)/CCN) heterostructure was prepared using the chemical bonding between carboxyl groups and -NH2 groups. Compared with the octahedral morphology of pure NM-101(Fe), the chemical bonding interaction promoted the heterogeneous nucleation and growth of NM-101(Fe) to form nanometer-sized granular morphology, which was homogeneously dispersed on CCN surface. Cr(Ⅵ) and ciprofloxacin (CIP) were selected as the typical pollutant models in micro-polluted water sources. The results showed that 10 %NM-101(Fe)/CCN heterostructure could remove 97 % of Cr(Ⅵ) in 60 min and 88 % of ciprofloxacin (CIP) in 120 min. In the dual pollutant system of Cr(Ⅵ) and CIP, Cr(Ⅵ) reduction and CIP degradation can promote each other, and the degradation efficiency of CIP reached 96 % within 120 min. The apparent rate constant of 10 %NM-101(Fe) /CCN heterostructure for Cr(Ⅵ) reduction was 4.30 and 9.67 times of that of NM-101(Fe) and CCN, respectively, which may be ascribed to the interface electric field and good interface bonding of heterojunction. The charges separation efficiency was significantly improved, which effectively enhanced the photocatalytic activity.