Cotton-Based Activated Carbon Fiber with High Specific Surface Area Prepared by Low-Temperature Hydrothermal Carbonization with Urea Enhancement

The traditional preparation method of activated carbon fiber is high-temperature carbonization and activation. In this experiment, cotton-based activated carbon fiber was prepared by urea-enhanced low-temperature hydrothermal carbonization and activation method. A specific surface area of 2304.8 m2/g of activated carbon fiber prepared by low-temperature hydrothermal carbonization with urea enhancement was the maximum reported using biomass as a raw material, which was higher than that of activated carbon fibers prepared by other biomass raw materials. X-ray photoelectron spectroscopy and elemental analysis studies have shown that the form of N transformed and decomposed during the high-temperature process, leading to the separation of C–N. Thermogravimetry mass spectrometry characterization analysis found that K2CO3 of low-temperature hydrothermal-assisted KOH activation may fully react with the N-containing group produced during the carbonization process to generate NH3, which lead to the formation of more pore structures in the carbon materials. The adsorption capacity of activated carbon fiber activated by hydrothermal-assisted KOH for iodine could reach up to 2254.8 mg/g. This process provides a new idea for the preparation of high-performance activated carbon fibers.