Nano-zerovalent copper as a Fenton-like catalyst for the degradation of ciprofloxacin in aqueous solution

Abstract

Ciprofloxacin (CIP), an important class of antibiotics is greatly used and discharged into aquatic environment which causes severe environmental issues. In this study, nano-scaled, stable, and highly reactive zerovalent copper (Cu°) was synthesized for the treatment of ciprofloxacin (CIP) in aqueous solution. The Cu° is an important material due to its high reduction potential and thus significantly degrade emerging organic pollutants. Besides, the Cu° synthesized in this study showed good surface area (i.e., 16.89 m2/g) and caused 63 % removal of CIP at 105 min under the conditions of [Cu°]0 = 0.5 g/L and [CIP]0 = 10 ppm. However, when H2O2 was used with Cu°, the removal of CIP was promoted from 65 to 85 % at 105 min using [Cu°]0 = 0.5 g/L, [CIP]0 = 10 ppm, and [H2O2]0 = 40 ppm,. CIP removal by Cu°/H2O2 was due to ●OH that showed high reactivity, i.e., 3.95 × 109 (M s)–1 towards CIP. The use of high [H2O2]0 and [Cu°]0 but lower [CIP]0 promoted the removal of CIP. The change in pH, addition of inorganic ions, and use of ●OH scavengers also influenced the removal of CIP by Cu°/H2O2. Total organic carbon (TOC) removal of CIP was investigated and showed 78 % removal of TOC at 800 min. Degradation products (DPs) of CIP were investigated to establish degradation pathways. The Cu°/H2O2 was found to have high potential in the removal of CIP in aqueous solution as it resulted in high TOC removal of CIP, and formation of inorganic DPs and non-toxic acetate.