Microwave-assisted one-pot method preparation of ZnO decorated biochar for levofloxacin and Cr(Ⅵ) removal from wastewater

Abstract

ZnO based-double functional biochar (ZnO-BC) derived pine sawdust is prepared by microwave heating using simple one-pot method for levofloxacin (LEV) and Cr(Ⅵ) removal from wastewater. ZnO-BC has well developed pore structure with BET surface area of 915.47 m2/g, which also has well ZnO crystalline. These characteristics make ZnO-BC available as the adsorbent and photocatalyst for LEV and Cr(Ⅵ) removal wastewater. LEV and Cr(Ⅵ) adsorption date fit well with the Hill and Pseudo-second order equation with LEV and Cr(Ⅵ) adsorption amount of 193.42 and 21.03 mg/g, respectively. The LEV and Cr(Ⅵ) adsorption behavior are determined by the chemisorption process. The hydrogen bond, π-π interaction, surface complexation, pore filling are responsible for LEV removal. While the hydrogen bonding, complexation and redox are crucial to the removal of Cr(Ⅵ) from wastewater. LEV removal is 85.72–97.19% at 15–25 mg/L at 120 min, and Cr(Ⅵ) removal is 72.62–99.9% at 40–60 mg/L at 75 min under UV irradiation. The possible photocatalytic mechanisms of the LEV and Cr(Ⅵ) are further investigated and analyzed.