Heterogeneously catalyzed persulfate with activated carbon coated with CoFe layered double hydroxide (AC@CoFe-LDH) for the degradation of lomefloxacin

Abstract

Activated carbon coated with CoFe layered double hydroxide (AC@CoFe-LDH) as an efficient catalyst of activating persulfate (PS) for the degradation of lomefloxacin (LMF) was successfully prepared and characterized. Various effects of reaction parameters on LMF degradation including PS dosage, catalyst concentration, initial pH and temperature were systematically studied. Results indicated that AC@CoFe-LDH nanocomposites exhibited ultra-high activity for PS activation compared with bare AC, modified AC (AC-HCl) and CoFe-LDH, in which 93.2% of LMF could be removed within 60 min by the AC@CoFe-LDH with an AC to CoFe-LDH ratio of 1:1 activating PS. It was also found that the condition of 1 g·L−1 PS, 0.2 g·L−1 catalyst, solution pH of 5 and reaction temperature of 25 °C was optimized. In the reaction system, both SO4− and HO were responsible for the LMF degradation and SO4− was the primary one. The cycles of Fe(II)/Fe(III) and Co(II)/Co(III) were confirmed by XPS analysis which revealed the proposed mechanism for PS activation. Moreover, AC@CoFe-LDH nanocomposites with good stability and recyclability showed great potential for the oxidative treatment of organic contaminants.