ZnO-NPs/AC composite antibacterial agents with N-halamine glycinate functionalized silica-mesoporous silica coating for water disinfection

This work deals with the synthesis, structural characterization and applications of N-halamine glycinate functionalized silica-mesoporous silica coated ZnO-NPs/AC composite for water disinfection. Several nanocomposite materials were obtained: ZnO-NPs/AC, ZnO-NPs/AC@SiO₂, ZnO-NPs/AC@SiO₂@mSiO₂, ZnO-NPs@SiO₂@mSiO₂-Gly and ZnO-NPs@SiO₂@mSiO₂-N-halamine-Gly. These nanocomposite materials were fully characterized via different physiochemical techniques including: FTIR, TGA, XPS, XRD, SEM, TEM and BET. XRD indicated a predominance of crystalline pattern of ZnO-NPs impregnated into activated carbon (AC) and their silica and m-mesoporous silica coating precursors. The FTIR spectra confirmed an immense combination between ZnO-NPs and AC of ZnO-NPs/AC nanocomposite as well as its interactions with coated silica precursors. SEM, TEM images illustrated that the fabricated ZnO-NPs/AC nanocomposites are well coated with silica-mesoporous silica functionalized N-halamine. The distinctive surface area has decreased from 800 m²/g for pristine AC to 772 m²/g for ZnO-NPs/AC and to 282 m²/g for ZnO-NPs/AC@SiO₂ and to 139 m²/g for ZnO-NPs/AC@SiO₂@mSiO₂ and to 15.4 m²/g for ZnO-NPs@SiO₂@mSiO₂-N-Gly. All those nanocomposites showed good efficacy against all four bacterial species, with higher inhibition zones for the 2 g-positive bacteria than that of the 2 g-negative ones. The ZnO@SiO₂@mSiO₂-N-halamine-Gly exhibited the high zone inhibition against all tested bacteria except for E. Coli.