Exceptional levofloxacin adsorption/photo-regeneration cycles using nanosheets-like hollow TiO2 adsorbent: Adsorption performance and mechanism

Abstract

Exploring efficient adsorbents still remains an important challenge due to the poor efficiency of the reported adsorbents for the adsorption of antibiotics. Herein, we design and prepare a novel nanosheets-like hollow TiO2 (NHT) adsorbent by using hollow TiO2 as a precursor through alkaline hydrothermal treatment. Adsorption results show that NHT exhibits a high adsorption percentage (98.05%) within 20 min and a maximum adsorption uptake of 24.51 mg/g for Levofloxacin (LVOF) pollutant (10 mg/L, 50 mL), which is 17 times higher than that (1.4 mg/g) of pristine hollow TiO2 (HT). Notably, NHT realizes >91% of the adsorption percentage for LVOF pollutant after the tenth run only through photo-regeneration without extra post-treatments, effectively overcoming the disadvantages of harsh regeneration procedures for most of the existed adsorbents. Adsorption data and the performance characterizations present deep insights into adsorption mechanism, which reveals that pore filling effect, hydrogen-bond interactions, and electrostatic attraction are the key parameters for the excellent adsorption of LVOF by NHT. Therefore, the present study can provide a promising direction for the fabrication of efficient adsorptive photocatalyst by using low-cost TiO2 as a precursor.