Towards the sustainable preservation of climacteric fruit by ethylene removal using MnxOy-carbon composites derived from agrifood waste

This work aims to integrate agricultural biomass residues in the development of appropriate materials for the removal of volatile organic compounds (VOCs) by combining adsorption and photocatalytic approaches. Ethylene was selected as target pollutant due to the importance of its removal in the control of climacteric fruit ripening. Activated carbons (ACs) were obtained by physical activation in CO 2 from baru waste and used either as adsorbents of ethylene, or as support of Mn x O y nanoparticles to obtain active photocatalysts by simple incipient impregnation. All samples were characterized by complementary techniques (physical adsorption of CO 2 and N 2 , XRD, SEM-EDX, FTIR, XPS, TG-DTG). Adsorption and photocatalytic assays were carried out in continuous fixed bed reactors. Breakthrough curves for ethylene adsorption were recorded in 100 ppm ethylene, air flow (25 cm 3 min –1 ) and under both dry and humid (RH = 50%) conditions. After saturation, the photo-oxidation of ethylene was studied under near-UV/Vis light irradiation at room temperature. The results indicated that, under these experimental conditions, the reaction proceeds selectively to CO 2 , with ethylene removal increases with Mn x O y content in the presence of humidity, reaching complete conversion at 10 wt.%.