Highly stable Fe on activated carbon catalysts for CWPO upon FeCl3 activation of lignin from black liquors

Iron-on-activated carbon catalysts for CWPO have been prepared through FeCl3-activation of lignin isolated from alkaline-pulping black liquors. The purpose of the chemical activation with FeCl3 is twofold; (i) produce carbon catalysts with a well-developed porous structure and (ii) introduce stable iron in the carbon matrix that acts as active phase in CWPO processes avoiding, or substantially decreasing, the iron leaching at the reaction conditions. The carbon catalysts obtained are essentially microporous with a relatively low amount of iron (less than 1 wt%). The increase of the activation temperature up to 800 °C favors a more homogeneous iron distribution through the carbon particles. The carbons obtained show a fairly good catalytic activity but mainly a very high stability, with almost no iron leaching at the reaction conditions analyzed.