ANALYSIS OF THE CONCENTRATION POLARIZATION OF TECHNOLOGICAL SOLUTIONS IN THE PROCESS OF THEIR NANOFILTRATIONAL SEPARATION

A method of determining the nonstationary concentration polarization of a solution, fl owing in a plane channel, in the process of nanofi ltration of the solution fl ow is proposed. The concentration polarization of the aqueous solutions, containing 0.5 kg/m3 of ZnSO₄ and SnSO₄, in the process of their nanofi ltrational separation was analyzed. It was established that an increase in the transmembrane pressure in a separation apparatus in the range Pm = 0.5–2.0 MPa causes the coeffi cient of concentration polarization of the ZnSO₄ and SnSO₄ solutions in this apparatus to increase in the ranges θ = 1.340–1.436 and θ = 1.351–1.430, respectively. A calculation of the time of work of a membrane in a stationary regime and the volume of the permeate obtained in it has shown that, before a membrane is regenerated, the nanofi ltrational separation of ZnSO₄ and SnSO₄ from their solutions at a defi nite pressure can be conducted for the times tm = 2070–2791 s and tm = 2893–2036 s, respectively. An increase in the transmembrane pressure causes these times to decrease and the amounts of the permeates obtained for the stationary-regime time to increase from 0.200 to 0.266 dm3 and from 0.202 to 0.262 dm3 , respectively.
A method of determining the nonstationary concentration polarization of a solution, fl owing in a plane channel, in the process of nanofi ltration of the solution fl ow is proposed. The concentration polarization of the aqueous solutions, containing 0.5 kg/m3 of ZnSO₄ and SnSO₄, in the process of their nanofi ltrational separation was analyzed. It was established that an increase in the transmembrane pressure in a separation apparatus in the range Pm = 0.5–2.0 MPa causes the coeffi cient of concentration polarization of the ZnSO₄ and SnSO₄ solutions in this apparatus to increase in the ranges θ = 1.340–1.436 and θ = 1.351–1.430, respectively. A calculation of the time of work of a membrane in a stationary regime and the volume of the permeate obtained in it has shown that, before a membrane is regenerated, the nanofi ltrational separation of ZnSO₄ and SnSO₄ from their solutions at a defi nite pressure can be conducted for the times tm = 2070–2791 s and tm = 2893–2036 s, respectively. An increase in the transmembrane pressure causes these times to decrease and the amounts of the permeates obtained for the stationary-regime time to increase from 0.200 to 0.266 dm3 and from 0.202 to 0.262 dm3 , respectively.
Author:  S. I. Lazarev, K. V. Shestakov, S. I. Kotenev, N. N. Ignatov
Keywords:  nanofi ltration, membrane, separation, concentration polarization, heavy metal ions
Page:  1045