A clean process for activator recovery during activated carbon production from waste biomass

► The proposed modified vacuum pyrolysis was environmental benign for biomass recycling. ► 99.99 % of the activator was recovered with no wastewater generation in the AC production process. ► The activator was recovered in the form of zinc chloride and metallic zinc. ► Resultant carbon exhibits high porosity and high adsorption affinity for phenol.