Macroscopic Zn-doped α-Fe2O3/graphene aerogel mediated persulfate activation for heterogeneous catalytic degradation of sulfamonomethoxine wastewater

Abstract

In order to obtain a robust, durable and efficient heterogeneous catalyst, macroscopic monolithic Zn-doped α-Fe2O3/graphene aerogel (GA) hybrid architecture with integrated morphology and hierarchically porous structure were controllably synthesized via a facile in-situ hydrothermal method and then used as persulfate (PS) activator for sulfamonomethoxine (SMM) wastewater purification. Several key reaction parameters including the initial SMM concentration, reaction temperature, coexisting inorganic anions and SMM in real natural water samples had different influence on the SMM removal efficiency. The catalytic efficiency of Zn-doped α-Fe2O3/GA with the molar ratio of Fe/Zn = 2:1.5 was about 66%, 62%, 66% and 11%∼33% higher than that of GA, α-Fe2O3/GA, Zn/GA and other Fe/Zn molar ratio. The improved activity of Fe/Zn = 2:1.5 benefits from the synergistic effects of the sp2 hybridized carbon and porous framework, as well as the surface oxygenic functional groups, which accelerate the pollutant/oxidant dispersion and electron transfer. Electron paramagnetic resonance results indicate that OH, 1O2 and SO4− radicals account for the catalytic degradation of SMM and the activation of PS in present system is different from conventional homogeneous systems, and speculate mechanism was proposed based on the obtained data.