Mechanochemically Scaled-Up Alpha Cyclodextrin Nanosponges: Their Safety and Effectiveness as Ethylene Scavenger

Aiming at the development of a greener ethylene removal alternative, the goal of this study was to scale up and ensure the safety of alpha-cyclodextrin nanosponges (alpha-CD-NS) for further use as ethylene scavengers. The solvent-free synthesis of alpha-CD-NS was successfully scaled up using acyclodextrin and N,N'-carbonyldiimidazole as cross-linkers (1:4 molar ratio) by means of mechanical alloying using a PM 100 ball mill by focusing on varying the rotation frequency, as determined by FTIR-ATR, X-ray diffraction, and TGA. alpha-CD-NS washing optimization was performed in water by monitoring the imidazole concentration in the washing solution through the validation of a fast and sensitive HPLC-DAD method. After 6 h at 40 degrees C, all imidazole was extracted, allowing a faster and less energy-dependent extraction. a-CD-NS absorbent capacity and porosity were also evaluated through BET isotherms and ethylene absorption experiments using a-CD-NS and commercially available absorbents (zeolite and bentonite) were performed by means of gas chromatography (GC) coupled to a flame ionization detector (FID). With a 93 mu L h(-1) kg(adsorbent)(-1) ethylene removal capacity, alpha-CD-NS revealed the best ethylene scavenging activity when compared to the other absorbents, opening the doors for a safer, innovative, and eco-friendlier ethylene removal active packaging.

Automated summary

This study aimed to scale up and ensure the safety of alpha-cyclodextrin nanosponges (alpha-CD-NS) for use as greener ethylene scavengers. By using solvent-free synthesis and optimizing washing in water, alpha-CD-NS showed the best ethylene scavenging activity, opening doors for safer, innovative, and eco-friendly ethylene removal active packaging.