Pore diffusion, shrinking core model

Model II Pore Diffusion in the Particles is r.d.s. (Knudsen Diffusion, Shrinking Core Model] If pore diffusion (Knudsen diffusion at HV) in the silica particles limits the mass loss and we assume that an IL-free shell is formed (shrinking core model), the mass loss is given by... 

The rate expression for solid diffusion control is obtained directly by. differentiation of the expression for the uptake curve for a spherical adsorbent particle subjected to a step change in sorbate concentration at the external surface [Eq. (6.4)]. Pore diffusion control with an irreversible isotherm leads to the shrinking core model and the uptake rate is therefore given by the differential of Eq. (6.27). 

A description of the coke burn-off process in a single particle by well-known closed solutions like the homogeneous or shrinking core model (Sections 4.6.3.4 and 4.6.3.5) is only reasonable for the border cases of complete control by chemical reaction or by pore diffusion. 

FigureS.IO Evaporation of supported IL ([EMIMJiNTfj], 174°C. HV. porous silica, Kieselgel 100, Merck, 0.06-0.2 mm) and comparison with the simulations by five models Model I effitsion from external surface of the silica particles is r.d.s., Eq. (6.23) Model II pore d rffusion in the particles is r.d.s. Knudsen diffitsion, shrinking core, Eq. (6.29)), Model III mass transfer in the sample is r.d.s. Knudsen diffusion infixed bed of crucible, Eq. (6.34)), Model IV effusion from face surface of sample is r.d.s. and p = p = constant, Eq. (6.37), and Model V effusion from face surface is r.d.s. " Fvap = PBET Psat...

---