3D N-doped graphene aerogel sponge-loaded CoS2 co-catalytic Fenton system for ciprofloxacin degradation

To avoid the loss of powder co-catalysts in metal sulfide-based co-catalytic Fenton process, we prepared a 3D N-doped graphene aerogel sponge-loaded CoS2 (SCG) and carried out a comparative study of ciprofloxacin (CIP) degradation in SCG/Fenton system, powdered CoS2/Fenton system, and conventional Fenton system. The results showed that SCG co-catalytic performance was comparable to that of powdered CoS2, the basic structure of SCG did not change after 10 times repeated experiments, and the leaching amount of Cox+ was less than 0.1 mg/L. Compared with conventional Fenton system, the content of Fe2+ in SCG/Fenton system and powdered CoS2/Fenton system increased from 1.05 mg/L to 8.2 mg/L and 7.9 mg/L, and the decomposition rate of H2O2 increased from 31.9% to 50.8% and 53.1%. The degradation rate constant of SCG/Fenton system was 0.1915 min−1, 5.7 times that of Fenton system and 1.2 times that of powdered CoS2/Fenton system, and SCG/Fenton system had a strong anti-interference ability against Cl−, NO3− and humic acid. 1O2 and ·OH played a leading role in CIP degradation. S2− and S22− on SCG surface acted as electron donors to accelerate Fe3+/Fe2+ conversion. The ecotoxicity of CIP degradation products was effectively eliminated. This study provides a reference for designing of 3D co-catalyst and a model for the application of co-catalytic Fenton system.