A dandelion-like NiCo2O4 microsphere with superior catalytic activity as the mediator of persulfate activation for high-efficiency degradation of emerging contaminants

Nowadays efficient treatment of emerging organic contaminants is still a complex task with a big challenge. Herein, a novel dandelion-like NiCo2O4 microsphere was synthesized by a simple step-by-step self-assembly strategy, and obtained NiCo2O4 was then as an efficient heterogeneous catalyst to activate PS for rapid degradation of emerging organic pollutants. Importantly, as-prepared NiCo2O4-300 microsphere not only exhibited great catalytic activity, but also possessed excellent performance stability and structural stability. More significantly, developed NiCo2O4-300/PS oxidation system displayed strong degradation ability toward typical contaminants, including TC, IBP, SMX, BPA, DFC as well as OFX. TOC analyses revealed that these organic pollutants could eventually be degraded into H2O, CO2 and other byproducts, and wherein degradation byproducts were low toxicity or no toxicity. During the process of PS activation over NiCo2O4-300, the redox couples of Co3+/Co2+ and Ni3+/Ni2+ provided major catalytic sites, and the redox couples of Ni3+/Ni2+ played a bigger role. Furthermore, it was also found that both SO4−• and •OH were main active species in the reaction system. Even in actual water samples, proposed NiCo2O4-300/PS oxidation system still showed great performance for removing pollutants. In short, current work would provide valuable references for further research.