Adsorption of methylene blue on natural cotton based flexible carbon fiber aerogels activated by novel air-limited carbonization method

A flexible carbon fiber aerogel material was synthesized from abandoned cotton by using air-limited calcination method. The activity of carbon fiber aerogel can be controlled by the calcination temperature and the loading weight of cotton (L-cotton) in the sealed container. The obtained material was characterized using SEM, FT-IR,BET and XPS. The results showed that the as-prepared carbon aerogels were fibrous and the surface of carbon aerogels can effectively form active groups after the calcination under air-limited condition. Samples with bigger specific area (457.73 m(2) g(-1)) and more active groups can be obtained at 600 degrees C and L-cotton = 0.25. Adsorption isotherm and kinetics of methylene blue on carbo fiber aerogels were determined from batch tests. The effects of contact time (1-100 min) and solution temperature (298 K-328 K) were investigated. The equilibrium data were best represented by Langmuir isotherm model, showing maximum monolayer adsorption capacity of 10223 mg g(-1), and the kinetic data was found to follow closely the pseudo-second-order kinetic model. Further-more, the calculation of thermodynamic parameters demonstrated that the adsorption process of methylene blue onto the carbon fiber aerogels was spontaneous, endothermic and random. These results proved that the carbon fiber aerogels could be a promising candidate for the treatment of dye wastewater. (C) 2017 Elsevier B.V. All rights reserved.