Three-dimensional recyclable FeS2/reduced graphene oxide aerogel with high porosity reticulated structure for efficient removal of tylosin tartrate

FeS2 has been applied in photocatalysis for removing organic pollutants in view of waste treatment by waste. However, powdered FeS2 still faces challenges such as easy recombination of photogenerated charges, susceptibility to corrosion, and difficulty in recycling. In this study, a three-dimensional FeS2/reduced graphene oxide aerogel (3D FeS2/rGOA) composite was synthesized through a self-assembly hydrothermal method to degrade the antibiotic tylosin tartrate. FeS2 was encapsulated by rGO and formed chemical bonds with it, creating a stable three-dimensional reticulated structure with well mechanical property, porous morphology and lightweight texture. The results showed that the FeS2/rGOA significantly improved the removal of tylosin tartrate, achieving 92.5%. The rGOA enhanced FeS2’s adsorption performance and narrowed the band gap of the composite, which improved its light absorption capacity. The reticulated structure of the rGOA facilitated electron transfer and extended the lifetime of photogenerated carriers. Moreover, the electron transfer channels in rGO resulted in electrons with longer lifetimes participating in reactions that generated free radicals. Additionally, it benefited to oxygen acting as an electron acceptor to produce hydrogen peroxide under acidic conditions regulated by FeS2, which is conducive to Fenton reaction. As a result, free radical quenching experiments and EPR tests showed that h+, ·O2–, ·SO4-, and ·OH were effective active species during the photocatalytic process. Furthermore, the stable chemical bonds between FeS2 and rGOA inhibited corrosion of FeS2. The three-dimensional structure of the composite with well mechanical property made it easy to recycle. The high stability and ease of recovery ensured the reuse of the FeS2/rGOA composite. The plausible degradation path of TYL was proposed based on the LC-MS results. This work provides a strategy for making FeS2 recoverable and highly catalytic for the degradation of antibiotics.