Efficient bacterial inactivation with S-doped g-C3N4 nanosheets under visible light irradiation.

The pathogenic bacteria in water that threatens the human health and photocatalytic disinfection have been proven to be a cost-effective and promising green technology. It is significant and necessary to develop efficient, safe, and visible light-driven photocatalysts. In this study, Escherichia coli was used as model bacterium and the disinfection performance of prepared S-doped g-C3N4 nanosheets (S-CNNs) under visible light was investigated. The results showed that the synergistic effects of S doping and the unique 2D structure of S-CNNs enhanced the visible light absorption, enlarged the specific surface area and reduced the recombination of photogenerated charge carriers which is beneficial for promoting the photocatalytic disinfection of the E. coli. Scavenger experiments indicated •O2- and h+ were the predominant reactive species in the photocatalytic disinfection process. In addition, the kinetics of disinfection activity were fitted by the modified Hom model and the k2 value of S-CNNs is 0.0219 min-1, which is much higher than that of the bulk g-C3N4 (CN). This work has demonstrated efficient bacterial inactivation with S-CNNs under visible light irradiation.

Impacts of cuprous oxide nanoparticles on wheat root morphology and genotoxicity.

To explore the ecotoxicity of Cu2O nanoparticles (NPs) on plant roots, the effects of Cu2O-NPs with different concentrations of 10, 50, 100 and 200 mg·L-1 on the seedling growth, root morphology, and cytogenetic toxicity of wheat 'Zhoumai 18' (Triticum aestivum Zhoumai 18) were examined in a hydroponic experiment. The results showed that Cu2O-NPs inhibited the growth of wheat seedlings. Cu2O-NPs reduced root and shoot lengths, fresh weights of shoot and root, root relative activity and ratio of root to shoot of wheat seedlings, but increased primary root number. Furthermore, with the increases of Cu2O-NPs concentrations, the root elongation zone shortened and the root became hard and brittle, while the average diameter of roots increased. Under the concentration of 100 mg·L-1 Cu2O-NPs, the mitotic index significantly decreased, and vacuolization, plasma membrane detachment, chromosomal abnormality occurred in the root tip cell. In conclusion, Cu2O-NPs are genotoxic to wheat seedlings, with consequences on the growth and development of wheat seedlings and root morphology.