Highly efficient nanocomposite of Y2O3@biochar for oxytetracycline removal from solution: Adsorption characteristics and mechanisms

Nano Y 2 O 3 -modified biochar composites (Y 2 O 3 @BC600) were fabricated successfully and exhibited great adsorption toward oxytetracycline (OTC). The Langmuir adsorption capacity of Y 2 O 3 @BC600-1:4 for OTC reached 223.46 mg/g, 10.52 times greater than that of BC600. The higher dispersion of Y 2 O 3 nanoparticles, increased surface area of 175.65 m 2 /g and expanded porosity of 0.27 cm 3 /g accounted for higher OTC adsorption by Y 2 O 3 @BC600-1:4. Y 2 O 3 @BC600-1:4 could resist the interference of co-existing cations (Na + , K + , Mg 2+ , Ca 2+ ) and anions (Cl − , NO 3 − , SO 4 2− ) on OTC removal. Y 2 O 3 coating changed surface charge property of BC600, favoring the contribution of electrostatic interaction. Synchrotron radiation-based Fourier transform infrared spectroscopy detected obvious peak shift and intensity change of surface –OH when OTC adsorption occurred. Accordingly, stronger H-bonding (charge-assisted hydrogen bond, OTC–H 2 N + ···HO–Y 2 O 3 @BC600-1:4) was proposed for OTC adsorption. Y 2 O 3 @BC600 exhibited renewability and stability in the adsorptive removal of OTC. Therefore, Y 2 O 3 @BC600 may be a novel and suitable adsorbent for antibiotic removal.