The concentration, which corresponds to t m = 1, was found by extrapolation of t m − C curves (inset of Figure 8). The r values were estimated as 7 nm (TiO2-HZD-2) and 4 nm (TiO2-HZD-7). Analysis of the curves shows that the Equations 7
and 8 give pore radius, which corresponds to peaks with maxima at 8 nm (TiO2-HZD-2) or 4 nm (TiO2-HZD-7). These peaks are attributed to necks of pores caused by particles II of the modifier, which evidently block pores of the matrix. Since intraporous diffusion double electrical layers are not overlapped at high concentration of the solution, the transport numbers of counter ions cannot reach 1. The transport number of counter ions is higher than 0.5 due to their excess in the diffusion part of the double AZD2171 ic50 electric layer [23].Based on data of electron microscopy, SAXS, porosimetry and potentiometric measurements, the structure of the composite membranes has been proposed. The matrix is formed by large particles of micron size; aggregates of smaller particles are placed on their surface (Figure 9). Matrix pores are blocked with aggregates of HZD nanoparticles. Figure 9 Structure of composite membrane. Blue circles = matrix; red-orange circles = ion exchanger. Pores between aggregates of particles of the ion exchanger are responsible for charge selectivity. These ‘corks’ isolate macropores, which
are recognized with the porosimetry method as predominant. see more Large particles of sol can penetrate the matrix during the first modification Elafibranor in vivo procedure. After blocking of the matrix pores, only the smallest particles are able to enter the membrane; Teicoplanin moreover, they form the loosening structure of the ion exchanger. Electrodialysis Anion exchange function of the inorganic membrane is provided by acidic media from the side of the concentration compartment. Thus, the transport of Na+ and Cl− ions was realized through the inorganic and polymer membranes, respectively. Cations and anions accumulated in the concentration compartment. A scheme of ion transport in the membrane system as well as through the inorganic membrane is given in Figure 10. Figure
10 Scheme of ion transport in the membrane system (a) and through the inorganic membrane (b). The limiting current density (i lim) can be calculated as [25]: (9) where k m is the mass transport coefficient, and z is the charge number. If the current density (i) is higher, than 0.75 i lim, both species of the solution and ions, which are formed at the membrane-solution interface due to water decomposition (H+ and OH−), are transported through the membrane. When the centre compartment is filled with glass particles, the following correlation equation can be applied to determine the mass transport coefficient [25]: (10) where Sh, Re and Sc are the Sherwood, Reynolds and Schmidt criteria, respectively. The criteria can be found as , and , where D is the diffusion coefficient in a solution (1.