The use of gases generated from eucalyptus carbonization as activating agent to produce activated carbon: an integrated process

By the first time, non-condensable gases generated at high temperature during wood carbonization in an industrial furnace were used as the activating agent for the preparation of activated carbon. The charcoal obtained from the carbonization step was employed as the starting material for the activation tests. Besides creating an application for these gases, the developed methodology is important to reduce costs related to the acquisition and heating of another activating agent. In addition to the production of activated carbons by itself, efforts were also focused on understanding how the presence of O-2 influences the performance of the activating mixture. The use of carbonization gases as activating agent permitted to obtain adsorbents with similar pore morphologies (evaluated through N-2 adsorption/desorption isotherms at 77 K) and adsorption capacities (iodine, phenol, and methylene blue) as those obtained by conventional activation with pure CO2, even though the process yield was lower. Activated carbons that met the specifications of Brazilian and international standards for application in water treatment were achieved with acceptable yields (in the order of 50%). The proposed integrated route implies technological, environmental, and economic gains for different industrial sectors.