Single-atom Co-N3 sites supported on waste paper-derived active carbon for synergistic adsorption and catalytic degradation of antibiotics

Single-atom catalysts (SACs) are emerging heterogeneous catalysts, which have been shown to be promising for a wide range of applications. Herein, we report the fabrication of single-atom Co sites with regulated Co-N 3 coordination supported on waste paper-derived active carbon (WPAC). The high specific surface area (535.2 m 2 g −1 ) and active Co-N 3 single sites endowed the Co-N 3 /WPAC with high adsorption capacity and excellent catalytic performance. The maximum adsorption capacity of sulfisoxazole (SIZ) onto Co-N 3 /WPAC reached 274.5 mg g −1 , and the removal percentage of SIZ reached ∼93.0 % within 1.0 min in the Co-N 3 /WPAC+PS system. The bifunctional properties of Co-N 3 /WPAC led to the efficient preconcentration of organic pollutants from aqueous solution as well as in-situ oxidation of them via the catalytic oxidation process. In addition, the Co-N 3 /WPAC+PS system exhibited a wide operating pH range (3−11), high mineralization capacity (∼89.3 %) and excellent reusability for the degradation of SIZ. Mechanism studies suggested that the Co-N 3 active sites were responsible for enhanced generation of the reactive oxygen species via PS activation, and both radical and non-radical processes contributed to the oxidation of SIZ. This work provides new insights into the resourceful disposal of waste paper and the application of SACs for environmental remediation.