Plasma-catalytic oxidation of ethylene over zeolite-supported catalysts to improve the storage stability of agricultural products

摘要

This work involved an investigation of the plasma-catalytic process, which consists of two steps: repeated cycles of adsorption to concentrate the ethylene and plasma catalysis to decompose the adsorbed ethylene. Investigations showed that the Pd/ZSM-5 catalytic adsorbent, which is prepared by an ion-exchange method, was found to be capable of efficiently adsorbing highly volatile ethylene, even under the humid conditions prevalent in agricultural facilities. The conditions under which the catalyst was prepared with the aid of ion exchange also greatly influenced the adsorption performance. The appropriate ion-exchange conditions were found to be room temperature, no pH adjustment, and the use of PdCl2 as the precursor, and the optimal Pd content was in the range of 0.268(similar to)0.361 wt%. The dynamical adsorption and plasma-catalyzed oxidation of ethylene was carried out in a packed-bed plasma reactor with Pd/ZSM-5 pellets. The adsorbed ethylene could be completely oxidized to carbon dioxide during the plasma-catalyzed step. The effect of ethylene removal on the storage stability of agricultural products was examined using kiwi fruit and broccoli. These experiments demonstrated that ethylene removal could substantially enhance the storage stability of these products.