Emerging investigator series: 3D graphene anchored zerovalent Fe/Cu aerogel activating persulfate for efficiently 2,4 dichlorophenol degradation over a broad pH range

Abstract

Nanoscale zero-valent bimetals are receiving considerable attention because of their excellent capability to degrade organic pollutants in water; however, nanoparticle aggregation reduces their reactivity, and the difficult separation limits their general application. Herein, we have developed a novel graphene aerogel anchored nano zero-valent iron and copper (GA-Fe/Cu) composite for the removal of 2,4-dichlorophenol (DCP) through activation by persulfate (PS) under aerobic conditions. The results show that the GA-Fe/Cu aerogel exhibits outstanding performances in the DCP degradation by PS activation, which increase as the Fe/Cu loading increases from 3.1% [GA-Fe/Cu(3.1)] to 9.4% [GA-Fe/Cu(9.4)]. The GA-Fe/Cu(9.4) aerogel exhibits an optimal catalytic activity for DCP degradation (∼100%) by PS activation within 60 min (k₁ = 0.0748 min⁻¹). The degradation efficiency of DCP by GA-Fe/Cu(9.4) significantly increases with increasing PS concentration, and slightly decreases from 100% to 80% upon increasing the pH from 4.5 to 9.5. The SO₄˙⁻, ˙OH, and ˙O₂⁻ radicals are found to be the dominant reactive oxygen species (ROS) generated by PS activation with GA-Fe/Cu(9.4), while non-radical mechanisms induced by GA appear to be also responsible for the DCP degradation. In addition, 83.2% of DCP is found to be completely mineralized by this reaction system. Thus, the findings of this work provide an alternative route for the efficient removal of organic pollutants from water.