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ZoP Adsorptive removal of antibiotic and bacteria using novel adsorbent based on synthesized ZnO@SiO2 nanoparticles

autorzy: 1. NGUYEN HA LINH, Class 11A2 Bio- HUS High school for Gifted students, University of Science, Vietnam National University. 2.HOANG LY BAO LONG, Class 11A2 Chem - HUS High school for Gifted students, University of Science, Vietnam National University

We report the first study on core-shell synthesized ZnO@SiO2 nanoparticles as a novel adsorbent for removal of antibiotic and bacteria. The ZnO@SiO2 nanoparticles were characterized by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared (FT-IR) spectroscopy, Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and zeta potential measurements. Removal efficiency of beta-lactam antibiotic amoxicillin (AMX) using ZnO@SiO2 nanoparticles was greater than 90 % whereas Escherichia coli (E.coli) removal was higher than 87 %. The optimum effective conditions for AMX removal using ZnO@SiO2 were found to be pH 8, adsorption time 90 min and ZnO@SiO2 dosage 25 mg/mL, respectively. The maximum adsorption capacity reached to 40.8 mg/g that was much higher than other adsorbents. Adsorption isotherms of AMX on ZnO@SiO2 were fitted by Freundlich and Langmuir models. The electrostatic attraction between negative species of AMX and positively charged ZnO@SiO2 surface induced adsorption while removal of E.coli was governed by both electrostatic and hydrophobic interactions. Our study indicates that synthesized ZnO@SiO2 is novel core-shell material for antibiotic and bacteria removal in water environment. Removal of antibiotic AMX and bacteria E.coli using synthesized core-shell ZnO@SiO2 nanoparticles was investigated in the invention. The ZnO@SiO2 nanoparticles were thoroughly examined by XRD, EDX, FT-IR, TEM, BET and zeta potential measurements and found to be mean particle size 30 nm; vibration groups of Si-O-Si, Zn-O and OH; specific surface area 29.6 m2/g; point of zero charge 8.7 Optimum conditions for AMX removal using ZnO@SiO2 were found to be pH 8, adsorption time 90 min and adsorbent dosage 25 mg/mL. Under optimum conditions, removal of antibiotic amoxicillin (AMX) using ZnO@SiO2 nanoparticles was about 90 % and a very high adsorption capacity of 52.8 mg/g was achieved. Freundlich could fit the adsorption isotherms of AMX on ZnO@SiO2 better than the Langmuir model. The E.coli removal was greater than 87 % that was much higher than other adsorbents. Adsorption of AMX on ZnO@SiO2 governed by electrostatic whereas adsorptive removal of E.coli was controlled by both electrostatic and hydrophobic interactions.