3D printing of hierarchically porous lightweight activated carbon/alumina monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel

Hierarchically porous materials have shown extensive applications in the domain of adsorbing environmental contaminants. Herein, a novel approach utilizing a 3D printing-freeze-drying strategy was presented to successfully design a hierarchically porous lightweight three-dimensional activated carbon/alumina (3D-AC/Al2O3) monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel. 3D-AC/Al2O3 monolithic adsorbents can exhibit superior adsorptive desulfurization performance at room temperature, as well as good cycling performance, thermal and mechanical stability. With incorporating designed 3D-printed liquid redistributor to enhance mass transfer within fixed bed, 3D-AC/Al2O3 can achieve 96.6 % sulfur removal with the sulfur adsorption capacity of 10.13 mg-S/g-Ads for feed oil of high initial sulfur content. Benefited from the hierarchical porous structure to form micron-millimeter scale adsorption micro-channel, feed oil can enter the interior of the monolithic adsorbents and fully contact with the adsorptive active sites to enhance the mass transfer. Further-more, through the design of the "adsorption-elution" reaction process, it becomes possible to accomplish both the removal of sulfides from feed oil through adsorption and the recovery of value-added sulfides that adsorbed onto the adsorbents. This simultaneous achievement highlights the practical potential for application in this context. Notably, the integrated 3D-AC/Al2O3 adsorbent exhibited promising desulfurization effects for application of real hydrogenated diesel.