Sandwich-like CoAl-LDH/Ti3C2 MXene composites enabling synergistic peroxymonosulfate activation for enhanced atrazine degradation

Abstract

The ongoing influx of organic contaminants into water systems, propelled by swift industrial expansion and socio-economic advancement, has resulted in considerable environmental repercussions. In this study, a sandwich-like structure, CoAl-LDH/MXene (LM-x), was synthesized via a one-step in-situ hydrothermal method to activate peroxymonosulfate (PMS) for the effective degradation of atrazine. The optimal LM-75/PMS system provides a remarkable degradation efficiency with complete ATZ degradation in 10 min. The unique structure of CoAl-LDH grown in-situ on MXene nanosheets not only exposes more active sites, but also realizes the strong interaction between Co and Ti. The system demonstrated excellent adaptability across a wide pH range (3−9) and under various saline-alkaline conditions, maintaining its superior ATZ degradation capability over multiple cycles. Radical quenching experiments and electron paramagnetic resonance results show that the radical pathway and non-radical pathway act together in ATZ degradation. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy confirmed the special electron transfer properties of MXene, enhancing the redox cycling of Co in the catalyst. Additionally, three degradation pathways for ATZ were proposed. This study provided new ideas for the development of environmentally friendly Co-based catalysts.