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Novel Crayfish Shell Biochar Nanocomposites Loaded with Ag-TiO2 Nanoparticles Exhibit Robust Antibacterial Activity

Zeng, Yifan, Xue, Yingwen, Long, Li, Yan, Jinpeng
Water, air, and soil pollution 2019 v.230 no.2 pp. 50
Escherichia coli, antibacterial properties, biochar, nanocomposites, nanoparticles, nanosilver, silver, silver nitrate, solar radiation, titanium dioxide, water treatment
A fast sol-dipping-gel method was applied to load Ag and TiO₂ nanoparticles on the surface of crayfish shell biochar to make an inexpensive and novel nanocomposite. Tetra-n-butyl titanate (Ti(OC₄H₉)₄) and silver nitrate (AgNO₃) were used as the nanoparticle precursors. Crayfish shell was pyrolyzed to produce the biochar host. Paper-disk diffusion method was applied to measure antibacterial activities of the nanocomposites to E. coli. The maximum loading rate of TiO₂ and Ag nanoparticles on the biochar reached 7.54% and 3.20%, respectively. Results of long-term antibacterial effect experiment showed that the Ag-TiO₂-biochar had robust antibacterial activity and could be reused for multiple times. The inactivation of E. coli of initial concentration of 10⁵ CFU/mL by Ag-TiO₂-biochar under solar light reached around 99% of sterilization ratio in 5 min. In addition, the antibacterial ability of the nanocomposite was better in light than that in dark due to the presence of TiO₂. Findings of this study suggest that the novel nanocomposite is a promising material for water treatment units and household water purifiers.