Applicability of blocking laws in non-Newtonian fluid membrane filtration

The blocking laws for constant flux non-Newtonian fluid filtration were derived by means of the Rabinowitsch–Mooney equation in the form of different first-order derivative expressions of pressure change over filtered volume dP/dV. The modified blocking laws were found theoretically sound as the modified equations reduced to those of classical blocking laws if the value of flow behavior index of Newtonian fluid was inserted. Dead end, constant flux microfiltration experiments of kaolin, titanium oxide (TiO₂), and sodium carboxymethyl cellulose at different concentrations (0.25–2% w/v) and at different fluxes (80 and 120 L/m²/h) were conducted to investigate the impact of non-Newtonian fluid behavior due to particle dispersion in water and soluble material on membrane filtration. It was found that the rheology of the fluid changed due to material retention on the membrane which led to conclusion that the model was not fully confirmed and, thus, its applicability might be insufficient to elucidate fouling mechanisms in constant flux, non-Newtonian fluid filtration.