NiFe2O4/N-CNT mediated peroxydisulfate activation via radical and non-radical pathways for water purification

Abstract

Metal oxide catalysts can significantly enhance the efficiency of the peroxydisulfate (PDS) activation to decompose refractory organic pollutants, and advanced strategies for improving the activation performance of the catalysts include exposing more metal active sites, optimizing the electronic structure, and enhancing cycling stability. Herein, a novel NiFe2O4/N-CNT composite was synthesized by the simple hydrothermal process. Additionally, the performance of the prepared catalysts can be adjusted by varying the content of N-doped precursors. The prepared NiFe2O4/N-CNT nanostructures had excellent activation properties for PDS, leading to sufficient free radicals and non-free radicals to degrade dyes. The system required only 0.07 g·L−1 of catalyst and 0.1 g·L−1 of PDS to degrade 100 mL (0.1 g·L−1) of reactive brilliant blue KN-R, and the degradation rate could reach 93 % within 30 min. The pH range was also wider, with excellent degradation under strong acidic conditions (pH=1). Moreover, it was highly adaptable to the common anions (Cl-, NO3-) and natural organic humic acid (HA) in the water body. This study expands the idea of the activation mechanism of peroxydisulfate (PDS) and successfully prepares catalysts for the effective degradation of organic dyes, showing the promising application of synergistic interaction between radicals and non-radicals in the degradation of persulfate.