Facile fabrication of MOF and natural polymer-derived carbon-aerogels with multiscale porosity for persulfate activation in water treatment

Abstract

Heteroatom-doped carbon materials have attracted significant attention as efficient catalysts for sulfate radical-based advanced oxidation processes (SR-AOPs). However, the practical application of powdered carbon materials has been hindered by challenges related to reusability. In this study, we developed a sustainable, reusable, and high-performance cobalt- and nitrogen-doped carbon aerogel (CoNCA) using agarose (AG) and zeolitic imidazolate framework-67 (ZIF-67) as metal-free catalysts for SR-AOPs. ZIF-67 acted as cobalt-doped carbon, while AG served as a porous, freestanding matrix to capture ZIF-67 during freeze-drying and pyrolysis. The CoNCA demonstrated excellent catalytic performance, achieving 95% methylene blue decomposition within 4 min through the activation of peroxymonosulfate. We systematically investigated the effects of PMS, catalyst, and organic pollutant dosages, along with pH and temperature variations, on catalytic performance. The CoNCA also exhibited excellent dye removal performance through immersion and pyrolysis processes, demonstrating high reusability. The material's high recovery rate using simple magnetic treatment highlights its feasibility as a purification filter. Moreover, the CoNCA exhibited catalytic efficiency in the degradation of 2,4,6-trichlorophenol, achieving 80% decomposition within 30 min. This approach presents a facile, reusable, sustainable, and high-performance carbon aerogel with a porous structure, offering significant potential as a next-generation metal-free catalyst.