Porosity Evolution of Activated Carbon Fiber Prepared from Liquefied Wood. Part I: Water Steam Activation at 650 to 800 °C

Activated carbon fiber is known as an excellent adsorbent material due to its well-developed pore structure. In this work, the porosity evolution of activated carbon fiber prepared from phenol liquefied wood with water steam activation at 650 to 800 degrees C for 20 to 260 min was examined by physical adsorption of N2 at - 196 degrees C. By the series of activation processes, the specific surface area and pore volume were increased with the increase of activation time, most significantly by activation at 750 degrees C for 20 to 180 min and by activation at 800 degrees C for 20 to 260 min. The microporosity was gently and progressively developed with increasing activation time at 650 to 700 degrees C, while it was sharply developed at the early stage of activations at 750 to 800 degrees C, and then tended to almost stabilize. The mesoporosity was well developed only by activation at 800 degrees C for longer than 100 min. The pore size distributions were principally ultramicropores (0.5 - 0.7 nm) during activations at 650 to 700 degrees C. By activations at 750 to 800 degrees C, the supermicropores (0.7 to 2.0 nm) as well as mesopores (2 to 4 nm) became progressively more important as the activation time was increased.