Sustainable synthesis of porous carbon with molecular sieve-like properties from waste biomass-derived heavy oil via dual green activation strategy for enhanced aqueous environmental remediation

Abstract

Biomass-derived porous activated carbon (BPAC) inherently features a hierarchical pore structure, making it versatile for diverse applications. For water treatment, effective pollutant adsorption hinges on specific pore architectures, with most pores in the BPAC structure contributing minimally. Therefore, it is particularly important to develop porous carbon materials with concentrated pore structure. This study develops a binary green activation strategy to rationally convert heavy bio-oil (HBO), an ideal carbon precursor with inherent properties, into porous carbon with molecular sieve-like properties, overcoming structural limitations of conventional BPAC. The porous carbon adsorbents demonstrate well-developed porosity with concentrated channels and high specific surface area (1807 m² g⁻¹), achieving an exceptional methylene blue adsorption capacity of 819 mg g⁻¹ which surpasses commercial activated carbon by 1.91-fold. Adsorption experiments indicate that the Langmuir and pseudo-second-order kinetic models can better describe the adsorption process. Finally, the mechanism by which the synergistic activation effect of “calcium-bridging potassium-etching” between the binary activators promotes the formation of carbon molecular sieves was revealed. This work provides a new approach for the rational design of HBO-based carbon molecular sieve materials.