NiCo₂O₄-loaded sunflower husk-derived biochar as efficient peroxymonosulfate activator for tetracycline removal in...

In this study, biochar produced from sunflower seeds husk was activated through ZnCl₂ to support the NiCo₂O₄ nanoparticles (NiCo₂O₄@ZSF) in catalytic activation of peroxymonosulfate (PMS) toward tetracycline (TC) removal from aqueous solution. The good dispersion of NiCo₂O₄ NPs on the ZSF surface provided sufficient active sites and abundant functional groups for the adsorption and catalytic reaction. The NiCo₂O₄@ZSF activating PMS showed high removal efficiency up to 99% after 30 min under optimal condition ([NiCo₂O₄@ZSF] = 25 mg L^-1, [PMS] = 0.04 mM, [TC] = 0.02 mM and pH = 7). The catalyst also exhibited good adsorption performance with a maximum adsorption capacity of 322.58 mg g^-1. Sulfate radicals (SO₄^•-), superoxide radical (O₂•-), and singlet oxygen (¹O₂) played a decisive role in the NiCo₂O₄@ZSF/PMS system. In conclusion, our research elucidated the production of highly efficient carbon-based catalysts for environmental remediation, and also emphasized the potential application of NiCo₂O₄ doped biochar.