Highly Monodisperse NiO QDs Embedded in rGO Sheets: Synergetic Effect of Adsorption and Antibacterial Properties in Water Treatment

In this paper, the hybrid composite of NiO quantum dots (QDs) ∼2 nm in diameter embedded in reduced graphene oxide (rGO) nanosheets with an average thickness of 1 nm was synthesized by a one-pot facile wet chemical method. The cost was reduced using NiO instead of Ag NPs, and the embedded NiO QDs can prevent the rGO sheets from aggregation, maintaining their high surface area and active sites. The NiO-rGO composite was used as adsorbent for phage f2 and MS2, and the adsorption capacity could be up to 107 PFU/mg with removal efficiency for MS2 up to ∼90 % in 30 minutes, while that for f2 up to ∼80% in 20 minutes. The composite also showed antibacterial properties towards E. coli. Paper disk diffusion assay, MIC and MBC tests revealed good antibacterial properties of the NiO-rGO composite. The synergetic effects on both phage adsorption and antibacterial properties would make the cheap NiO-rGO hybrid composite usable in water treatment.