Cotton-derived three-dimensional carbon fiber aerogel with hollow nanocapsules and ultrahigh adsorption efficiency in dynamic sewage treatment system

An ultralight 3D carbon fiber aerogel with good flexibility is developed via soaking cotton in water and then calcinating at a high temperature. This cotton-derived carbon material is constituted by amorphous carbon and retains slight oxygen-containing groups. Besides, a lot of hollow carbon nanocapsules are yielded on the inside surface, resulting in abundant micropores and mesopores. Systemic investigations explore the molecular transformation from cotton to carbon fiber, and the formation of carbon nanocapsules. In the adsorption process for methyl orange (MO), this carbon fiber aerogel exhibits both a rapid adsorption rate and the ultrahigh adsorbability of 862.9 mg/g, outclassing most of carbon materials reported. Therefore, a dynamic sewage treatment system is built and consecutively removes hydrosoluble pollution for a long-term running time. For the cotton-derived carbon fiber aerogel, the good mechanical flexibility, excellent adsorption property, and high stability jointly provide a vast application prospect in future industrial wastewater remediation.