Mass transfer intensification by modifying structured packing surface properties produced with 3D foam-printing technology

• Tailored surface packings by in-situ 3D foam-printing. • Surface enhancement and absorption process intensification. • Foaming techniques to control PLA sheet absorption performance. • Hierarchical micro-structures and surface roughness to enhance gas–liquid interfacial area. • CO 2 as a sustainable foaming agent for biobased PLA. Gas–liquid contactors have a pivotal importance in chemical engineering, as they influence the mass transfer rate in many processes, e.g. distillation, absorption, and desorption. This study explores the potential of 3D foam-printing technology to enhance structured packing surfaces by integrating both micro-textures and micro-roughness through foaming. The aim of the work is to create advanced and customized contactors with a high gas–liquid interfacial area for packed-bed column applications. By combining 3D printing with foaming techniques several textured sheet samples, representing the repetitive units of structured packing, were produced using biobased polylactic acid (PLA) and CO 2 as a foaming agent. Rather than using a full-scale packed column, absorption experiments were performed using a lab-scale setup based on the inclined-wall falling-film system. The setup involved a single rectangular flat sheet under complete wetting conditions to simulate packing performance between loading and flooding points. Textured sheets were compared to smooth sheets and included designs such as rectangular steps, triangular steps, pyramidal, wavy, and wavy triangular steps. Optical analysis (using SEM and confocal microscopy) revealed that texture inclusion via 3D printing increased surface area by 15–22% compared to the benchmark. Foamed samples showed an additional surface area increase of up to 50%, with the highest gain (52%) seen in the wavy triangular step texture. The absorption experiments showed that foamed sheet samples provided higher mass transfer efficiency, confirming that the textures and micro-roughness enhance the gas–liquid interface. Among the textures tested, the wavy triangular step was the most effective although wavy and pyramidal textures (commonly used in commercial packing) have a larger area of about 15–16%. These findings confirm that 3D foam-printing is a viable option for producing the next generation of tailor-made, highly efficient surfaces for advanced packed-bed column applications.