Preparation and characterization of composite multichannel capillary membranes on the way to nanofiltration

Capillary nanofiltration membrane modules can combine favorable properties such as high packing densities, low costs and beneficial fouling behavior of tubular and spiral wound modules. To achieve further improvement of mechanical strength and specific membrane surface per volume, multichannel capillary membranes (MCMs) with several feed channels within one fiber have been developed. This paper presents salt rejection and pure water flux performance data of novel composite MCMs. The new composite capillary membranes were fabricated by a dry-jet wet spinning process and subsequent interfacial polymerization. The influence of the dope composition on the membrane structure and the separation performance of composite MCMs were studied. When tested at an operation pressure of 0.5 MPa and 20 °C, the MCMs had a rejection of MgSO4 and CaCl2 of 57% and 21% respectively and a pure water flux of about 47 L/m2h.