| Autor: |
Chugunov, A. S., Vinnitskii, V. A., Stepanyuk, K. V. |
| Zdroj: |
Membranes and Membrane Technologies; May 2021, Vol. 3 Issue: 3 p192-197, 6p |
| Abstrakt: |
Abstract: The paper discusses experimental data on the mutual effect of concentrations of NaCl and MgCl2salts during their transport across a Vontron VNF2-1812 nanofiltration membrane at low specific loads of the feed stream, which imply the occurrence of concentration polarization near the membrane surface. Separation is run at a minimum difference between the operating pressure maintained in the forcing channel (0.3 MPa) and the calculated osmotic pressure (0.25 MPa for all individual and mixed solutions used). It is shown that, under the studied conditions, the water flux is almost independent of the ratio of salt concentrations in the solution in the separation chamber; with an increase in the specific load of the feed stream on the membrane, the water flux exhibits a tendency to achieving a limiting value. It is found that, for conditionally isopiestic NaCl and MgCl2solutions, the dependence of the salt flux on the molar fraction of the respective salt is nonlinear. This finding can be attributed to the nonlinear relationship between the absolute and relative concentrations of salts in the feed stream and the dependence of their interdiffusion coefficients in mixed solutions on composition. Techniques to improve the efficiency of the nanofiltration separation of differently charged cations are described. |
| Databáze: |
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