Photocatalytic Activity of Composites for Ethylene Degradation Under UV-A and Visible Light

Abstract

Ethylene is a natural hormone responsible for many processes, including ripening. One way to extend the shelf life of several fruits and vegetables is to remove ethylene from the atmosphere of storage and transport, for which photocatalysis processes can be an efficient technology. In this study, we investigated the ethylene photodegradation of four different composites (Cu/C3N4, Cu/TiO2, Ni/C3N4, Ni/TiO2) under UV-A and visible illumination. The photocatalytic composites were characterized, and the photocatalytic assay was performed in a continuous system for 1 h (ethylene concentration at 1.0 % in synthetic air, 50 mL.min-1, and 400 mg of photocatalyst). The results indicated that the Cu/C3N4 sample did not produce carbon dioxide under visible light or UV-A illumination, so ethylene was not degraded. The Ni/TiO2 sample had the best performance for ethylene degradation under visible light and UV-A illumination, showing higher CO2 production with UV-A. After illumination for 1 h, the light was turned off, and 5 min later, the CO2 concentration at the outlet was equal to the initial. Thus, the composites Ni/C3N4, Cu/TiO2, and Ni/TiO2 proved to be efficient in ethylene degradation. Therefore, they can increase the shelf life of fruits and vegetables, using photocatalysis to remove ethylene from the atmosphere while storing and transporting these foods.