Shafieiyoun, SaeidThomson, Neil R.2018-06-292018-06-292018-06-01https://doi.org/10.1016/j.jconhyd.2018.04.002http://hdl.handle.net/10012/13453The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jconhyd.2018.04.002 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/An experimental and computational study was performed to investigate the role of multi-component intra-NAPL diffusion on NAPL-water mass transfer. Molecular weight and the NAPL component concentrations were determined to be the most important parameters affecting intra-NAPL diffusion coefficients. Four NAPLs with different viscosities but the same quantified mass were simulated. For a spherical NAPL body, a combination of NAPL properties and interphase mass transfer rate can result in internal diffusion limitations. When the main intra-NAPL diffusion coefficients are in the range of self-diffusion coefficients (10−5 to 10−6 cm2/s), dissolution is not limited by internal diffusion except for high mass transfer rate coefficients (>180 cm/day). For a complex and relatively high viscous NAPL (>50 g/(cm s)), smaller intra-NAPL diffusion coefficients (<10−8) are expected and even low mass transfer rate coefficients (~6 cm/day) can result in diffusion-limited dissolution.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Intra-NAPL diffusionIntra-NAPL concentration gradientsRate-limited mass transferMGP residualsArticle