Ethylene Adsorption Study by Using Various MOFs in the CMC Film for Application in Postharvest of Fruit

Metal–organic frameworks (MOFs), Bio-MOF1, HKUST-1 and Cu(II)@Bio-MOF1 have been prepared and characterization for the study of ethylene adsorption. Cu(II)@Bio-MOF1 was post-synthesis material by the exchange process between DMF cation in the porous of Bio-MOF1 and Cu(II) ion. It was modified because biocompatible anion Bio-MOF1 shows low efficiency of ethylene adsorption while HKUST-1 shows a good one with open metal (Cu²⁺) active site for attraction of ethylene. MOF films were synthesized by carboxymethyl cellulose biopolymer and cross-link agent, citric acid mixed with the prepared MOFs, Bio-MOF1, HKUST-1 and Cu(II)@Bio-MOF1. These MOFs in the form of powder and MOF films have been studied for ethylene adsorption. Gas chromatography and observing banana peel color change were used to analyze ethylene adsorption. The color change of banana peel from green to yellow represents the ripening. HKUST-1 shows the best ethylene adsorption and the slowest color change to yellow of banana peel. Cu(II)@Bio-MOF1 exhibits better efficiency of ethylene adsorption than Bio-MOF1. In addition, prepared MOF powder provides higher efficiency of ethylene adsorption than the prepared MOF films. It is possible that ethylene gas was obstructed by biopolymer to penetrate the active sites of MOF.