Skimmilk crossflow microfiltration performance versus permeation flux to wall shear stress ratio

Crossflow microfiltration (MK) of skimmilk with a ceramic membrane(0.1 mu m mean pore diameter) for the separation of casein micelles from whey proteins was performed at various constant flux, J (30-109 l h(-1) m(-2)) and efficient wall shear stress, tau(weff) (23-97 Pa). The ratio (J/tau(weff)) constitutes a basic parameter which characterizes competition between of convection and erosion at the membrane/solution interface. A critical value of (J/tau(weff)) around 1.0 1 h(-1) m(-2) Pa-1 has been found: when (J/tau(weff)) < 1.0 l h(-1) m(-2) Pa-1, MF performance was satisfactory: long MF time with slow increase of fouling resistance and high whey protein transmission with slow decrease; when (J/tau(weff)) > 1.0 l h(-1) m(-2) Pa-1, short MF time with sharp increase of fouling resistance and sharp decrease of transmission. This critical value of (J/tau(weff)) could be used as a predicative parameter for MF process permeability and selectivity for various operating conditions.