Effect of Temperature on Water Flux

Temperature in the stirred cell is measured with a PTIOO probe and is accurately adjusted to 20 C 1 C using a waterbath. To study temperature effects, the beaker water temperature was adjusted between 15 C and 40 C using ice or a hot water bath, respectively and flux measured as a function of wall temperature. Solvent dynamic viscosity changes with temperature follow the equation by Worch (1993) 

Permeate flux increases on decreasing viscosity and therefore a higher permeability is achieved at higher temperatures. A common method to account for this change with temperature is to multiply the obtained flux with the viscosity ratio with respect to a reference temperamre. If temperature effects on flux are only influenced by changes in viscosity, then the product of flux and viscosity should be constant. 

It can be seen that temperature effects are significant for the NF membranes. As a consequence, temperature was controlled using a waterbath (see Chapter 4 for details). 

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Figure 4.19 Effect of temperature on water flux through an alumina membrane...

Temperatrue influences system flux and rejection performance. Figures 9.3 and 9.4 shows the effect of temperature on water flux and salt rejection. 

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