Degradation of perfluorooctanoic acid (PFOA) using multiphase fenton-like technology by reduced graphene oxide aerogel (rGAs) combined with BDD electrooxidation

Abstract

Perfluorooctanoic acid (PFOA) pollution in aqueous environments has attracted considerable attention. Due to its high chemical stability, PFOA is very difficult to degrade, posing potential risks to human health. Therefore, it is of significance to find an efficient and eco-friendly way to remove PFOA from the environment. In this study, reduced graphene oxide aerogel (rGA) was loaded with Fe3O4 and Cu nanoparticles (NPs) to obtain Fe3O4-rGA and Cu-rGA, which were then prepared into cathodes using the microbubble templating method. Heterogeneous Fenton-like system coupling Fe3O4/Cu-rGA cathodes and boron-doped diamond (BDD) electrodes were used to efficiently degrade PFOA in aqueous solutions. The parameters for PFOA degradation were optimized to be initial current density of 20.0 mA cm−2, initial electrolyte pH of 6, and electrolyte (Na2SO4) concentration of 10 mM. After 360 min, the Fe3O4-rGA and Cu-rGA systems achieved PFOA removal efficiencies of 98.25 % and 98.91 %, respectively, which were 16.7 % and 17.5 %, respectively, higher than that achieved by the system using a commercial graphite electrode. PFOA was completely removed, in 720 min and the F− production rates were 62.29 % and 65.48 % in the Fe3O4-rGA and Cu-rGA systems, respectively. PFOA degradation followed pseudo first-order kinetics in both systems (R2 > 0.99). The results of free radical quenching experiment and electrochemical performance experiment showed that the abundant active sites and excellent electrocatalytic properties of Fe3O4-rGA and Cu-rGAs promoted the formation of ⋅OH radicals for efficient PFOA degradation. In conclusion, coupling heterogeneous Fenton-like systems with Fe3O4 or Cu NPs-loaded rGA and BDD electrooxidation have great potential in the treatment of PFOA wastewaters in the future.