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

A hydrodynamic approach developed by a wired-membrane module for reducing the effects of concentration polarization and progressive fouling in membrane ultrafiltration, has been carried out. The wired-membrane module is modified 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 out for various transmembrane pressures, feed concentrations, feed flow rates, and inclined angles of helical wire. Theoretical predictions were based on the resistance-in-series model and confirmed qualitatively with the experimental results. Considerable improvement of performance based on the same hydraulic dissipated energy, is obtainable by employing a wired-membrane module rather than using a tubular-membrane module without or even with a steel rod inserted concentrically.