MODELING OF DIFFUSION-ADSORPTION KINETICS OF 1-METHYLCYCLOPROPENE (1-MCP) IN APPLE FRUIT AND NON-TARGET MATERIALS IN STORAGE ROOMS

The purpose of this research was to model the kinetics of adsorption of 1-Methylcyclopropene (1-MCP) in apple fruit and 'non-target' solid materials found in apple storage rooms. A distinction is made between diffusion into the material and the adsorption. The process was therefore described by Fick's second law of diffusion of the gas through the pores of the material coupled with adsorption of the gas on the material's binding sites. A finite element formulation of the model, describing the diffusion and adsorption mechanisms separately, was first developed. The values of the relevant parameters were estimated based on head space measurements of the decrease of 1-MCP in dedicated jars with the different materials. The diffusion coefficient, adsorption coefficient and concentration of active site in the various solids were determined and were in the order of 10-9m2/s, 101 m3 mol-1 s-1 and 10-4 mol m-3 respectively. The model was validated with separate experimental data.