In-situ silver-modification of Silicalite-1 for trace ethylene capture under humid conditions

Abstract

The removal of trace C2H4 at high relative humidity has significant importance for the preservation of fruit; however, owing to the severe storage environment and competitive adsorption of high humidity water vapor and carbon dioxide, few suitable adsorbent materials are currently available for this application. Herein, silver-loaded silicalite-1 sorbent (S-1@Ag) was synthesized via an in-situ silver modification method to enhance its interaction with ethylene. By adjusting the amount of silver source to 0.94 wt%, the ethylene uptake of S-1@Ag at P/P0 of 0.01 was sixteen times greater than unmodified silicalite-1. S-1@Ag prepared using the in-situ method exhibits a uniform distribution of Ag+ that enhances the recognition of ethylene, resulting in an excellent ability to capture ethylene at low pressures. Crucially, S-1@Ag(0.94 %) was unaffected by the presence of water vapor and carbon dioxide in its application environment, and exhibits the best preferential adsorption of ethylene under low pressures. Dynamic breakthrough tests under humid conditions demonstrated that S-1@Ag(0.94 %) captures trace ethylene four times more effectively than S-1@Ag, even under different gas mixtures (C2H4/N2, 0.1/99.9, v/v; C2H4/CO2/N2, 0.1/0.1/99.8 and 0.1/1/98.9, v/v/v). Furthermore, banana storage experiments show that S-1@Ag(0.94 %) slows the decay time of the fruit and improves its storage life.