Preparation of CuCl₂ modified biochar for levofloxacin removal from municipal wastewater

The residual quantities of levofloxacin (LFX) in the ecology have caused extremely serious problems due to the misuse of LFX. Copper-modified biochar (Cu-BC) is prepared by co-pyrolysis of CuCl2 with fir sawdust (FS) for LFX removal by adsorption, activation of peroxydisulfate (PDS) degradation and the photocatalytic degradation process. The physicochemical properties of the Cu-BC were investigated and analyzed, which include Cu, Cu2O, and CuO. Cu-BC can adsorb LFX with an adsorption amount of 97.35 mg/g, which is larger than that of the original biochar (BC). The π-π interactions, H-bonding, and surface functional groups are responsible for LFX adsorption, based on adsorption mechanism analysis. Cu-BC activation PDS can highly efficient realize LFX removal. The e- generated from the Cu+/Cu2+ cycling are gathered around Cu to form the electron-rich center for achieving activation of PDS degradation of LFX, reducing its toxicity. While 1O2 and SO4•- significantly influence the LFX degradation process, based on degradation mechanism analysis. Besides, the Cu-BC can be used as the photocatalyst for LFX removal owing to the existence of Cu2O. The photocatalytic degradation mechanism of LFX is also put forward.