Selective Laser Sintering of Metal-Organic Frameworks: Production of Highly Porous Filters by 3D Printing onto a Polymeric Matrix

Metal-organic frameworks (MOFs) have raised a lot of interest, especially as adsorbing materials, because of their unique and well-defined pore structures. One of the main challenges in the utilization of MOFs is their crystalline and powdery nature, which makes their use inconvenient in practice. Three-dimensional printing has been suggested as a potential solution to overcome this problem. We used selective laser sintering (SLS) to print highly porous flow-through filters containing the MOF copper(II) benzene-1,3,5-tricarboxylate (HKUST-1). These filters were printed simply by mixing HKUST-1 with an easily printable nylon-12 polymer matrix. By using the SLS, powdery particles were fused together in such a way that the structure of the printed solid material resembles the structure of a powder bed. The MOF additive is firmly attached only on the surface of partially fused polymer particles and therefore remains accessible to fluids passing through the filter. Powder X-ray analysis of the printed object confirmed that printing did not have any negative impact on the structure of the MOF. CO2-adsorption studies also showed that the activity of the MOF was not affected by the printing process. SLS offers a straightforward and easy way to fabricate tailor-made MOF-containing filters for practical applications.