Facile synthesis of graphene nano zero-valent iron composites and their efficient removal of trichloronitromethane from drinking water

• A binary nanocomposite-graphene and nanometer-sized zero-valent iron (G-nZVI) has been facilely prepared.
• The as-prepared G-nZVI could effectively remove trichloronitromethane (TCNM) from water.
• The degradation pathway of TCNM by G-nZVI nanocomposites might include dechloration and denitration.
• The activity of the used G-nZVI could be restored by calcinations again.

Halonitromethanes (HNMs), as an emerging class of disinfection by-products containing nitrogen (N-DBPs) in drinking water, have possessed public health concerns. Two most studied materials, graphene and nanometer-sized zero-valent iron, have been successfully combined into binary nanocomposites (G-nZVI) via facile carbonization and calcinations of glucose and ferric chloride, which was used in the removal of HNMs from drinking water in this study. When the Fe/C mass ratio was 1:5, the as-prepared G-nZVI hybrids comprised numerous dispersed Fe0 nanoparticles with a range of 5–10 nm in diameter. Batch experimental results indicated that the as-prepared G-nZVI could effectively remove trichloronitromethane (TCNM), a dominant in the group of HNMs from drinking water. About 99% of initial TCNM could be adsorbed and degraded under 60 mg/L G-nZVI dosage within 120 min. Kinetic studies indicated that the removal of TCNM by G-nZVI followed a pseudo first order rate (R2 > 0.9). The degradation pathways of TCNM by G-nZVI nanocomposites might include dechlorination and denitration of TCNM. The Fe was in the form of iron oxides in the graphene material shape which was then restored to Fe0 again via calcinations. These results indicated that the synthesized G-nZVI nanocomposites could be a powerful material to remove HNMs from drinking water.