Sorption Arrhenius plots

Arrhenius plot showing comparison of corrected sorption diffusivities (D0) and NMR self diffusivities (Ds) for A, butane and B, propane in 5A zeolite crystals. (x,o 55pm and 27pm Charnell crystals I. , 34pm and... 

Fundamental studies of gas transport in polymers other than rubbers began with the classical work of Meares in 1954 He was the first to demonstrate and theorize about the now well-known inflection in the Arrhenius plots of D near the ass transition temperature. He also speculated abcut two modes of sorption in glassy polymers. Later studies were initiated with many polymers by Barrer, Michaels and their coworkers together with important contributions by Brandt, Stern, Stannett and many others ... 

Figure 2. Arrhenius plot showing comparison of NMR and sorption diffusivities for benzene and o-xylene in NaX zeolite crystals. NMR data from (1) Germanus et al. (19) and (2) Karger and Ruthven (10). Uptake (corrected diffusivity) and tracer exchange data of Goddard (11-13) (50 pm and 100 pm NaX, 250 pm faujasite). ZLC data of Eic (15,16).

Figure 4. Arrhenius plot showing comparison between sorption, ZLC and NMR diffusivity data for n-butane in 5A zeolite crystals. Data from Karger and Ruthven (10), Yucel and Ruthven (9) and Eic (15).

The Arrhenius plot of the rate constant of the surface discharging (ko) and the rate constant of oxygen sorption (k ) indicate that the mechanism of interaction in the NiO/oxygen system exhibits a change at 300°C involving a diffusion-controlled process above 300°C and a surface diffusion regime below this temperature (Figure 4.24). 

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