The composite metal cluster catalyst Ni–MCM enhances the non-radical pathway for efficient catalytic degradation of norfloxacin

Abstract

Norfloxacin (NOR) is a synthetic antibacterial agent that is extensively applied in the management of various infectious conditions. After entering the human body, most of it cannot be absorbed and is excreted, eventually reaching natural waters. At the same time, it promotes the generation of drug-resistant bacteria, which seriously threatens human health. In this study, a simple mechanical mixing method was employed to synthesize a Ni–MCM composite catalyst with excellent stability, which was utilized for the degradation of NOR. The effects of the mass ratio of Ni–MC to MCM-41, initial pH value, starting NOR concentration, catalyst dosage and inorganic anions on NOR degradation were studied. The findings indicate the superior degradation capability of Ni–MCM towards NOR under diverse conditions. Quenching experiment and electron paramagnetic resonance spectroscopy showed that when dissolved oxygen occupied the active site of the metal in the catalyst, more ˙O₂⁻ and ¹O₂ would be formed, and NOR would be degraded due to the interaction with the mixed system composed of ˙OH and SO₄˙⁻ and electron transfer, indicating that the degradation mechanism of the Ni–MCM system was dominated by non-free radicals. The utilization of the Ni–MCM nano-composite catalyst is a promising approach for the treatment of wastewater containing norfloxacin.