Tuning of Delicate Host–Guest Interactions in Hydrated MIL‐53 and Functional Variants for Furfural Capture from Aqueous Solution

Capture of high‐boiling‐point furfural from diluted aqueous solution is a critical but challenging step in sustainable bio‐refinery processes, but conventional separation methods such as distillation and liquid‐liquid extraction requires prohibitive energy consumption. We report control over the microenvironment of hydrated MIL‐53 and isoreticular variants with diversified functional terephthalic acid linkers for the purpose of preferential binding of furfural through delicate host‐guest interactions. Methyl‐bounded MIL‐53 with improved binding energy in the hydrated form results in highly efficient capture ratio (ca. 98 %) in the extremely low concentration of furfural solution (0.5–3 wt %) and 100 % furfural specificity over xylose. The distinct hydrogen bonding sites and multiple Van de Wall interactions for furfural adsorption was testified by computational modeling. Furthermore, the recovery ratio of furfural reaches ca. 93 % in desorption. Functional linkers in hydrated MIL‐53 frameworks are tuned to achieve a delicate host–guest interaction that drives highly efficient capture of bio‐furfural as a prominent building block from diluted aqueous solution. A distinct hydrogen‐bonding linkage between furfural and materials was identified at molecular level by DFT calculations, along with gaining binding energy that shows preference of materials to furfural in thermodynamics.