Synthesis and Characterization of Novel Core-Shell ZnO@SiO2 Nanoparticles and Application in Antibiotic and Bacteria Removal

A novel core-shell nanomaterial, ZnO@SiO2, based on rice husk for antibiotic and bacteria removal, was successfully fabricated. The ZnO@SiO2 nanoparticles were characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET) method, diffuse reflectance ultraviolet-vis (DR-UV-vis) spectroscopy, Xray photoelectron spectroscopy (XPS), Raman spectroscopy, and zeta-potential measurements. beta-Lactam antibiotic amoxicillin (AMX) was removed using ZnO@SiO2 nanoparticles with an efficiency greater than 90%, while Escherichia coli removal was higher than 91%. The optimum effective conditions for AMX removal using ZnO@SiO2, including solution pH, adsorption time, and ZnO@ SiO2 dosage, were 8, 90 min, and 25 mg/mL, respectively. The maximum adsorption capacity reached 52.1 mg/g, much higher than those for other adsorbents. Adsorption isotherms of AMX on ZnO@SiO2 were more in accordance with the Freundlich model than the Langmuir model. The electrostatic attraction between negative species of AMX and the positively charged ZnO@SiO2 surface induced adsorption, while the removal of E. coli was governed by both electrostatic and hydrophobic interactions. Our study demonstrates that ZnO@SiO2 based on rice husk is a useful core-shell nanomaterial for antibiotic and bacteria removal from water.

Automated summary

A novel core-shell nanomaterial based on rice husk, ZnO@SiO2, was successfully fabricated for antibiotic and bacteria removal. The nanomaterial exhibited high efficiency in removing AMX and E. coli, with adsorption capacity higher than other adsorbents. The study demonstrates the potential of ZnO@SiO2 as a useful core-shell nanomaterial for water treatment.