Metal–Organic Framework Based on α-Cyclodextrin Gives High Ethylene Gas Adsorption Capacity and Storage Stability

Abstract

Two metal−organic framework (MOF) materials, that is, α-cyclodextrin (α-CD)-MOF-Na and α-CD-MOF-K, were successfully synthesized and exhibited excellent adsorption capacity and storage stability for ethylene gas. The ethylene encapsulation capacity of α-CD-MOF-Na and α-CD-MOF-K reached 47.4 and 52.9% (w/w), respectively, which was significantly higher than those of other materials reported such as α-CD and V-type starch. The release characteristics of ethylene inclusion complexes (ICs) were determined under different temperatures and relative humidity conditions. The ethylene gas could be stably encapsulated in α-CD-MOF-ethylene ICs at 25 °C for up to 30 days. The crystal structure of α-CD-MOFs was determined to explain their high capacity and stability for ethylene storage. Molecular simulation was used to model the location of ethylene molecules in α-CD-MOFs. Alpha-CD-MOF-Na and α-CD-MOF-K showed "8"-shaped and spindle-shaped cavity, respectively, which effectively adsorbed and stored the ethylene gas. Accelerated ripening experiments showed that 5 mg of α-CD-MOF ICs could ripen bananas within 4 days, with an effect similar to that of free ethylene gas. We suggest that α-CD-MOF materials are an excellent material for ethylene storage with potential application in industrial and agricultural areas.

Recent Advances of Porous Materials Based on Cyclodextrin

“…Owing to the charming structures, porous materials based on CDs are favored by researchers in various fields such as drug delivery, [ 77–79 ] adsorption and separation, [ 80,81 ] gas storage, [ 82 ] sensing, [ 83–85 ] and so on.…”

“…This is due to the unique structure of α ‐CD‐MOF‐K, which limits the escape of ethylene molecules. [ 82 ]…”

Triggered and controlled release of active gaseous/volatile compounds for active packaging applications of agri‐food products: A review

“…Although MOF complexes exhibited poor storage stability, the α‐CD–MOF complexes have high stability, being more stable than α‐CD complexes under ambient conditions. Hence, α‐CD–MOF had higher ethylene encapsulation capacity and storage stability when compared to MOFs and CDs (Li et al., 2020).…”

Preparation and anticorrosion properties of GO‐Ce‐MOF nanocomposite coatings

“…They are suitable for a wide range of applications, including gas storage or separation, catalysis, drug delivery, and imaging. [25][26][27][28] Due to MOFs' importance in practical applications, people have recognized MOFs' importance in the past few years. Seidi et al 29 reviewed the less application of MOF in epoxy resin coatings, and emphasized its application prospects with epoxy resin in terms of anti-corrosion, flame retardant, mechanical and dielectric properties.…”

“…MOF materials have extraordinary permanent porosity, large pore volume and low density and high‐specific surface area. They are suitable for a wide range of applications, including gas storage or separation, catalysis, drug delivery, and imaging 25–28 . Due to MOFs' importance in practical applications, people have recognized MOFs' importance in the past few years.…”