Improvement of ultrafiltration performance in tubular membranes using a twisted wire-rod assembly

A hydrodynamic approach developed by a wired-membrane module for reducing t he effects of concentration polarization and progressive fouling in membran e ultrafiltration, has been carried out. The wired-membrane module is modif ied from a tubular-membrane module by inserting concentrically a steel rod wrapped entirely with a tight fitting wire spiral, having a diameter nearly equal to the annular spacing, as a spacer. Experiments for ultrafiltration of dextran T500 aqueous solution in a wired-membrane module was carried ou t for various transmembrane pressures, feed concentrations, feed flow rates , and inclined angles of helical wire. Theoretical predictions were based o n the resistance-in-series model and confirmed qualitatively with the exper imental results. Considerable improvement of performance based on the same hydraulic dissipated energy, is obtainable by employing a wired-membrane mo dule rather than casing a tubular-membrane module without or even with a st eel rod inserted concentrically. (C) 2000 Elsevier Science B.V. All rights reserved.