Cathodic membrane with confined interlayer spacing for efficient electrocatalytic dehalogenation of antibiotics

Abstract

Conventional catalytic membranes often exhibit inadequate catalytic efficiency due to limited retention time for pollutants during filtration. In this study, a single-atom catalyst (Ni-NG) was prepared by dispersing single nickel atoms onto nitrogen-doped graphene oxide sheets. Subsequently, under controlled conditions, the assembly of Ni-NG with reduced graphene oxide (rGO) sheets led to the fabrication of efficient electrocatalytic cathodic membranes (ECMs). The ECMs were designed to concentrate and dehalogenate antibiotics simultaneously by utilizing the confined single nickel atoms within the multilayered ECMs through electrocatalytic reduction. Remarkably, complete degradation of chloramphenicol (CAP, 20 mg L−1) in the solution was achieved within a remarkably short time of 3.0 ms by ECM8 which had an area of 7.1 cm2 and comprised Ni-NG (16.9 μg) and rGO (16.9 μg), with an interlayer spacing of 0.37 nm, during filtration (40 L m−2 h−1). The reaction rate constant (k) for CAP degradation by ECM8 was approximately 3 × 108 min−1, surpassing the highest value in the literature. Furthermore, the ECM demonstrated both high energy efficiency and stability, highlighting the great potential for practical applications. The electrocatalytic cathodic membrane, designed to primarily concentrate pollutants in confined interlayer spaces through the sieving effect, shed lights on the highly efficient dehalogenation of organic compounds in pharmaceutical salt-laden wastewater.