Amino-functionalized synthesis of MnO2-NH2-GO for catalytic ozonation of cephalexin

Abstract Catalysts such as MnO 2 always play a critical role in catalytic ozonation, which is applied extensively in water treatment for disinfection, odor removal and organic pollutants degradation. To improve the performance of catalytic ozonation, we design and synthesize a catalyst of amino-functionalized hybrid of MnO 2 and graphene oxide (MnO 2 -NH 2 -GO) with hydrothermal method, and then use it to catalyze the ozonation of cephalexin (CLX), one of β-lactams antibiotics frequently detected as refractory pollutants in aquatic environment. The MnO 2 -NH 2 -GO shows much higher catalytic performance than both MnO 2 and MnO 2 -GO in the ozonation of CLX, in which the free radicals of · O 2 − play a dominated role and the Mn 3+ /Mn 4+ acting as active sites react with ozone to promote the formation of · O 2 − with the help of the enhanced electron transfer facilitated by GO. The MnO 2 -NH 2 -GO also shows more stable catalytic performance than MnO 2 -GO due to the strong covalent bonds bridged by amino to MnO 2 and GO to prevent the decoupling of GO from MnO 2 . This work provides a method to design a smart catalyst for ozonation with high catalytic performance and stability.