Efficient mineralization of ciprofloxacin using a 3D Ce_xZr_1−xO₂/RGO composite cathode

Abstract

3D columnar CexZr1−xO2/RGO composite electrodes were prepared based on a hydrothermal self-assembly method and were used as cathodes to degrade ciprofloxacin (CIP) for the first time in an electro-Fenton system.

Selective Electrocatalytic Reduction of Oxygen to Hydroxyl Radicals via 3‐Electron Pathway with FeCo Alloy Encapsulated Carbon Aerogel for Fast and Complete Removing Pollutants

“…Radical quenching experiments were conducted to identify the active species generated during electrochemical activation of O 2 ,u sing Tert-butanol (TBA) and superoxide dismutase (SOD) to scavenge COH and CO 2 À ,respectively.As exhibited in Figures 2d and S7, the addition of TBAl ed to asignificant decrease of k obs from 1.44 AE 0.04 min À1 to 0.05 AE 0.02 min À1 ,d emonstrating that CIP was eliminated through the surface catalytic oxidation by COH. Additionally,the CIP degradation efficiencyd ecreased significantly with k obs of 0.07 AE 0.02 min À1 in the presence of SOD,e ven no BMPO-CO 2 À signal was detected during EPR analysis.T hese results manifested that O 2 was firstly reduced to CO 2 À intermediate via 1-electron pathway,which followed by subsequent reduc- [11] Ce 0.75 Zr 0.25 O 2 /RGO, [12] MnCo 2 O 4 -CF, [13] Fr-ErGO, [14] Ni-CF [15] )for the CIP removal in electrocatalytic degradation processes.…”

“…Once H 2 O 2 is formed via 2-electron pathway,e xploring whether the generated H 2 O 2 is desorbed from the surface of Fe 0.5 Co 0.5 Corfurther reduced to produce COH and OH À via 1electron pathway is necessary. [26] According to Equations (12) and ( 13), the kinetic inclination of COH reduced from *H 2 O 2 could be acquired via the actual barriers of forming COH and OH À under ac ertain potential. Therefore,w eh ave determined the eventually generated species by comparing the calculated free energies of producing COH and OH À from *H 2 O 2 according to the thermodynamic formulas [Eqs.…”

“…with CeO 2 /RGO, [11] Ce 0.75 Zr 0.25 O 2 /RGO, [12] MnCo 2 O 4 -CF, [13] Fc-ErGO [14] and Ni-CF [15] as cathodes, respectively.M oreover, k obs in homogeneous EF system (C/ Fe 2+ )w ith carbon aerogel as cathode and Fe 2+ as Fenton catalyst were 0.11 AE 0.01 min À1 under the same conditions. Remarkably,F e 0.5 Co 0.5 Cc athode had the k obs of 1.44 AE 0.04 min À1 to be 7-144 times higher than other catalysts.…”

“…d) Comparison of the reaction rate under different quenching conditions. e) Comparison of k obs and J among various electrodes (Fe 0.5 Co 0.5 C, C/Fe 2+ ,C eO 2 /RGO,[11] Ce 0.75 Zr 0.25 O 2 /RGO,[12] MnCo 2 O 4 -CF,[13] Fr-ErGO,[14] Ni-CF[15] )for the CIP removal in electrocatalytic degradation processes.…”

Modified carbon felt made using CexA1−xO2 composites as a cathode in electro-Fenton system to degrade ciprofloxacin

“…As shown in Fig Ce 0.75 Zr 0.25 O 2 . 35,36 It was shown in Fig. 2b, the most frequently observed reection with a d spacing value of 0.314 nm corresponds to crystal lattice plane (1 1 1) of CeO 2 .…”