The biorefinery process using renewable biomass such as (hemi) cellulose and lignin as raw materials contributes to the sustainable development of global economy.

Capture of high-boiling-point furfural from diluted aqueous solution is a critical but challenging step in sustainable biorefinery processes. Conventional separation methods such as distillation and liquid-liquid extraction requires prohibitive energy consumption.

Recently, a group led by Prof. YANG Weishen from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences reported 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.

The results were published in Angew. Chem. Int. Ed. on Oct. 6. 

The scientists constructed isoreticular stable metal-organic framework (MOF) materials with diversified functional terephthalic acid linkers. Methyl-bonded hydrated MIL-53 showed highly efficient capture ratio (~98%) in the extremely low concentration of furfural solution (0.5-3 wt.%) and 100% furfural specificity over xylose.

In collaboration with DEND Weiqiao's group from Shandong University, the researchers identified a distinct "hydrogen-bonding-linkage" between furfural and materials at molecular level by means of detailed DFT calculations, along with gaining binding energy that showed preference of hydrated frameworks to furfural in thermodynamics.

Furthermore, the recovery ratio of furfural reaches ~93% in desorption, was holding promise for recovery of furfural and the recycling of MOF materials in the actual industrials.

This work was supported by the National Natural Science Foundation of China.