Tailored hierarchically textured 3D-printed carbon monoliths for enhanced liquid-phase adsorption under flow conditions

Abstract

This work introduces a design strategy for adsorption monoliths, in which porous texture and flow architecture are independently tuned to enhance liquid-phase adsorption performance under flow conditions. Hierarchically textured 3D-printed carbon monoliths with engineered, interconnected channel architectures are developed for the adsorption of emerging contaminants, using sulfamethoxazole (SMX) as a model pharmaceutical pollutant. These materials are fabricated through a hybrid approach that integrates sol-gel polymerization of resorcinol (R), formaldehyde (F), and Cs2CO3 (Cs) with 3D printing. Adjusting the R/Cs ratio within the range of 100 to 2000 enables precise control over the macroporous texture, resulting in mean pore diameters between 95.1 and 157.1 nm while preserving the printed channel geometry and structural integrity. Among the resulting monoliths, Monolith-100 exhibits the highest adsorption capacity (61.4 mg g−1), attributed to π-π stacking and electrostatic interactions. In batch adsorption mode, the adsorption capacity decreases in the order Monolith-100 > Monolith-500 > Monolith-1000 > Monolith-2000, with increasing R/Cs ratio. In continuous flow tests, Monolith-1000 demonstrates superior adsorption performance, resulting in extended breakthrough times and reduced mass transfer zone height (HMTZ). The interconnected, 3D-printed geometry promotes enhanced SMX-adsorbent interaction via flow redistribution and mixing, achieving breakthrough times of up to 200 min with a reduced HMTZ, markedly longer than those of monoliths with conventional straight channels, which exhibit rapid breakthrough times (5 min). These findings demonstrate the potential of independent control over porous texture and structural design to optimize next-generation flow-through adsorption systems.