Degradation of ciprofloxacin by persulfate activation with CuO supported on Mg Al layered double hydroxide

Abstract

Abstract CuO is an efficient catalyst for persulfate (PS) activation. However, the leaching of Cu ions is usually serious and the improvement of CuO stability is highly desired for its practical application. Herein, CuO supported on Mg Al layered double hydroxide (LDH) and CuO-LDH composite were synthesized by two-step precipitation and co-precipitation methods, respectively. The leaching of Cu ions was avoided due to the high alkalinity and buffer capacity of LDH. CuO supported on LDH had larger surface area, higher alkalinity and more exposed CuO, thus exhibiting much higher activity than CuO-LDH composite. The sample with the Cu:Mg ratio of 1:1 (Cu4/LDH) exhibited the highest activity and could remove more than 99% of ciprofloxacin within 30\xa0min at pH 4–10. The removal efficiency was still above 94% in the presence of various coexisting substances. Moreover, it showed good stability and reusability. Activated PS generated via the non-radical pathway and SO4−• generated via the radical pathway were the dominant reactive species for ciprofloxacin degradation. The results indicate that Cu4/LDH is a promising catalyst for the removal of organic pollutants with PS activation.