The preparation of carboxylic-functional carbon-based nanofibers for the removal of cationic pollutants.

A simple route is presented to fabricate carboxylic-functional carbon-coated polyacrylonitrile nanofibers (oPAN@C) through preoxidation and hydrothermal carbonization. PAN fibers were firstly preoxidized to form aromatic ladder structure with the resistance to hydrothermal condition, in which more carboxyl groups were introduced on the fiber surface at the present of chitosan and citric acid. The oPAN@C composites exhibit a high adsorption capacity towards methylene blue (MB) and lead ion (Pb 2+ ). The adsorption data matched the pseudo-second-order kinetic model and Langmuir model well with the maximum adsorption capacity (153.37 and 143.27 mg g −1 ) for methylene blue and Pb 2+ , respectively. Moreover, oPAN@C could be regenerated easily by hydrochloric acid, and still remained high removal efficiency after 5 cycles. Therefore, oPAN@C fibers should have potential application in sewage treatment. [ABSTRACT FROM AUTHOR]