Activated Carbon Production from Coffee Waste via Slow Pyrolysis Using a Fixed Bed Reactor

Abstract Pyrolysis is a thermochemical process commonly used for bio-oil, bio-char, and syngas production. It is particularly attractive due to its cost-effectiveness and low environmental impact. Therefore, this study utilizes coffee waste to produce activated carbon in a slow pyrolysis reactor at different reaction temperatures and residence times. The results obtained in this study show that bio-oil yields tend to increase when moderate reaction temperatures and short residence times are used. In contrast, the bio-char yields are higher at low reaction temperatures and long residence times. The Scanning Electron Microscopic (SEM) images of the coffee waste, bio-char, and activated carbon indicate that the pore size of the bio-char tends to decrease due to heating and tends to increase in the area after using ZnCl2 as activating agent. Coffee waste is a suitable feedstock for activating carbon production.