ZnFe layered double hydroxide wrapped metal-organic framework derived cobalt-nitrogen-doped carbon material as peroxymonosulfate activator for ciprofloxacin degradation

[Display omitted] •ZnFe-LDH-3@CoNC/peroxymonosulfate shows excellent performance for ciprofloxacin removal.•ZnFe-LDH acts as both catalyst and sacrificial agent protecting cobalt active sites from leaching.•SO4•−, •OH, O2•−and 1O2 participate in the degradation of ciprofloxacin.•CIP transform pathways and mechanism over ZnFe-LDH-3@CoNC/peroxymonosulfate system are elucidated. ZnFe layered double hydroxide (ZnFe-LDH) wrapped metal–organic framework derived cobalt and nitrogen-doped carbon-based materials (ZnFe-LDH@CoNC) were synthesized. The fabricated nanocomposites exhibited uniform distribution of ZnFe-LDH-3 on CoNC matrix. Degradation efficiency of ciprofloxacin (CIP, 10 mg/L) in the peroxymonosulfate (PMS)-containing catalytic system reached up to 98.5 % at a dosage of 0.2 g/L ZnFe-LDH-3@CoNC and 0.4 g/L PMS at a reaction time of 30 min at 25 °C. The ZnFe-LDH-3@CoNC/PMS catalytic system was found to act as a pH buffer and it exhibited more stable activity in cyclic tests compared with the CoNC/PMS catalytic system. Quenching experiments and EPR analyses showed that 1O2 was the primary reactive species in the ZnFe-LDH-3@CoNC/PMS catalytic system. Degradation intermediate products of CIP were identified and a potential degradation mechanism was suggested. The ZnFe layered double hydroxide wrapped metal–organic framework advances methods in environmental catalyst design and simultaneously improves active metal for PMS activation.