Mass Transfer Driven Pore Engineering of Activated Carbon from Activation of Biomass

Abstract

Performance activated carbon (AC) from lies in precise control of its pore structure. Pore development in activation of biomass is essentially a dynamic process driven by mass transfer of volatiles and derivatives of activators. Therefore, this review systematically analyzes the mass transfer regulation mechanism during various scenarios for the preparation of AC with different biomass feedstocks under distinct reaction conditions. The discussion firstly it elaborates on how pyrolysis methods (microwave heating vs. conventional conductive heating), temperature gradients, and raw material composition affect the release of volatiles, diffusion pathways, carbon skeleton shrinkage behavior, and initial reaction network for formation of pore structure. The etching mechanisms and mass transfer characteristics of diverse activating agents are also discussed to reveal how infiltration/melting/diffusion of activating agents, penetration depth, and interfacial reactions with biomass constituents govern pore architecture and surface chemistry. Based on mass transfer mechanisms, targeted design strategies for tailoring pore and chemical properties of AC for various application scenarios (gas and macromolecular pollutant adsorption, supercapacitors, and advanced oxidation) are further proposed, providing new methodological support for the controllable preparation of high-performance functional carbon materials with desirable properties.