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.

Porous chitosan/hydroxyapatite composite membrane for dyes static and dynamic removal from aqueous solution

The unique characteristics of Chitosan (CS) such as resource abundance, good biocompatibility, film-forming ability and sufficient sites (NH₂ and OH) for adsorption of heavy metals or organic pollutants make CS-based membranes a promising membrane adsorbent. In this work, a porous Chitosan/Hydroxyapatite (CS/HA) membrane with a sponge-like surface and a three-dimensional interpenetrated porous structure of about mean pore size less than 10μm was developed. The most striking advantage of the proposed membrane lies on the integration of appreciably high adsorption capacity (as compared with current CS-based membranes, also 2.5 times and 4 times higher than that of non-porous CS/HA membrane and the commercially available activate carbon) and the high-speed dynamic dye removal (98% or even better in less than 15min). Besides, the synthesis protocol for the proposed membrane is also much simpler, environmental-friendly and economical. Moreover, the proposed membrane also featured repeated dye removal (above 80% after 5 cycles of dynamic adsorption at dye concentration of 150mgL^-1). All the above advantages indicated the intriguing potential of the porous membrane in practical wastewater treatment.