Appending Polyamines on Metal–Organic Frameworks as an Efficient Strategy for Selective Removal of H2S under Humid Conditions

Removal of highly toxic and corrosive hydrogen sulfide from gas flows is of paramount importance for controlling the environment and in several industrial processes. This contribution reports a straightforward strategy to engineer sorbents for efficient hydrogen sulfide removal under humid conditions by functionalizing the open metal sites of metal–organic frameworks (MOFs) with polyamines. MIL-101(Cr) MOFs were successfully modified with ethylenediamine and tris(2-aminoethyl)amine, and the resulting materials were characterized using X-ray diffraction, FTIR, NMR, nitrogen sorption, and thermogravimetric analysis (TGA), confirming the functionalization. Although the functionalized MOFs exhibited a greater affinity for water compared to the unmodified MIL-101(Cr), they efficiently removed H2S under humid conditions without framework degradation, whereas the pristine material did not. This was demonstrated by TGA-MS and elemental analysis and confirmed by density functional theory calculations. The developed approach offers a promising pathway for the design of advanced sorbents tailored for H2S removal in industrial and environmental applications.