Aiming for the valorization of agricultural biomass residues such as coffee husks and plastics wastes such as polyethylene terephthalate (PET), a method for transforming them into activated carbon by using ammonia chloride as activation agent is presented in this study. Firstly, mixtures of PET waste were processed through a pyrolytic process at different operational conditions through a factorial experimental design. The obtained material with the best characteristics of specific surface area (SSA) and mass yield was obtained at 600 °C and 2.5 hours of treatment. These parameters were then used for performing the activation of coffee husks residues and mixtures of them with PET (in mass rates of 1:1 and 1:2 of PET and biomass, respectively) All the obtained materials were then characterized through a Scanning Electron Microscopy - Energy Dispersive Spectroscopy (SEM–EDS), X-Ray Fluor...