Heteroatom doped cellulose nanocrystals (CNC) with chiral nematic liquid crystal interface for high efficiency removal of ciprofloxacin

Abstract

The increasing contamination of water systems by ciprofloxacin (CIP) has become a growing concern. The photocatalysis approach offers a promising strategy for the effective removal of CIP. In this study, MSx/CNC (MSx, M = Co, Ni, Cu) binary composites with chiral catalytic interfaces were prepared by chemical precipitation and the composite M0-MSy/CNC was prepared by energetic β-particle bombardment. The XPS results confirmed the successful construction of C–O−M bonds. TEM results clearly revealed the generation of sulfur vacancies (Sv) in the composites. The M0-MSy/CNC/peroxymonosulfate (PMS) photocatalytic system was also constructed in this study. The results of the application experiments showed that the Co0-CoSy/CNC/PMS system had an excellent degradation effect on CIP, which reached 100 % at 1.5 h of open light. The degradation kinetic constants of Co0-CoSy/CNC/PMS were 4.26 times higher than those of CoSx/CNC/PMS. In addition, EPR showed that the Co0-CoSy/CNC/PMS system generates ‧OH, ‧SO4−, ‧O2−, and h+ radicals to co-remove CIP. This study also elucidated the major intermediates of photocatalytic degradation of CIP at the chiral catalytic interface using LC-MS analysis. This work provides insights into the coupled application of photocatalysis and PMS activation in the remediation of aqueous environments.