Effective pore volume

In the classical model of the size exclusion mechanism this difference stands for the effective pore volume of the separating model. Any elution of samples or fractions outside this interval always means a perturbation by a different mechanism. Such conditions have to be avoided. It is not possible to expand this elution difference A significantly for a given column. For this reason, GPC column sets are considerably longer than LG columns for other mechanisms. 

Figure 18. Procedure for EPV (effective pore volume) measurement (a) a 50 g MnO, sample is placed in a 100 mL graduated cylinder (2) water is added gradually in 0.5 mL portions (3) with a stopper in place, the cylinder is turned upside down 10 times while being shaken (4) the cylinder is droppes 4 cm onto a wooden surface (5) the Mn02 sample volume is read after 5 and 10 taps (i.e., drops).

Figure 19. Model fo the sudden volume increase of Mn02 powder sample at EPV (effective pore volume) point, (a) water fills 50% of the pores (b) water fills almost 100% of the pores (c) when excess water (1-2 mL more than the pore volume) is added, the Mn02 volume suddenly increases by 5-10 mL since the particles stick to each over. The sudden increase (far more than the amount of water added) is shown as H in (3), stage (c), above.

From the variation of the volume of the EMD vs. the amount of added water, the EPV (effective pore volume) is obtained as shown in Fig. 19. 

Table 9. EPVs (effective pore volumes) IC and IBA Mn02 samples...

With a pore diameter of 2000 A it is conceivable that the adsorbed polymer layer could significantly reduce the effective pore volume. 

Carbon Effective pore volume, vp(tnic) (cm3g ) Pore range, w (nm)... 

In principle, the chemical composition of water recharging a lithologically homogeneous aquifer will depend upon the mineral phase present in the aquifer, the amount of dissolved carbon dioxide (H2CO3), the amount of aquifer surface area (S) in contact with the hydraulically effective pore volume (V), the temperature at which reaction occurs (T), the contact time (t), and the reaction rate (k). Laboratory experiments may be carried out using specific lithologic media to determine the rates of reaction of these media with water containing dissolved carbon dioxide. If the interrelationships of the above variables can be sufficiently defined, a determination of one of the above aquifer properties can be made, if the others are known, and if a representative water sample from the aquifer is available. 

Figure 2. Individual alkane concentrations measured in each effective pore volume collected during surfactant flooding for columns (a) 17.1-m, (b) 23.2-m, and (c) 26.2-m.

As noted earlier, the principal properties of nonideal porous media that establish the nature of the fluid flow are porosity, permeability, tormosity and connectivity. In a macroscopic sense, porosity characterizes the effective pore volume of the medium. It is directly related to the size of the pores relative to the matrix. When porosity is substituted, the details of the strucmre are lost. 

Figure 4.18 Procedure for EPV (effective pore volume) measurement (1) a 50g Mn02 sample is placed in a 100 mL graduated cylinder (2) water is added gradually in 0.5 mL portions (3) with a stopper in...

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