Osmotic Effects during Filtration through Composite Membranes Formed in Water Treatment Processes

The objects of the study are spent composite membranes on the basis of cartridge filters made of fibrous propylene. The analysis of the thermodynamic equations of osmotic processes suggests that such membranes can have salt-retaining properties. Experimental data on the filtration of the feed water in the radial mode through a composite membrane are obtained. It is shown that the removal of ionic forms of iron and manganese in the entire range of hydrostatic pressures and a decrease in the concentration of cations of alkaline earth metals in the filtrate at a pressure above 0.16 MPa are observed. This unequivocally indicates that, even in dialysis cells, whose permeability is limited only by the acquired hydrolocking properties, osmotic effects of transmembrane diffusion transfer of truly dissolved salts occur.