Jacek A. Wiśniewski

Effect of flow conditions on ultrafiltration efficiency of dye solutions and textile effluents

Abstract An ultrafiltration system with a tubular membrane module was used in an experimental study on the efficiency of organic dye removal from aqueous solutions and actual textile effluents. The module consisted of a polysulfone membrane which had been cast on the surface of a porous poly(methyl methacrylate) bar. It has been found that at an optimum velocity of feed flow (0.76 m/s), the retention coefficient for organic dyes of molecular weight greater than 780 exceeds 97%. A 200-h ultrafiltration of the textile effluent yielded removal efficiencies of 75–85% and 50–60% for COD and TOC, respectively. Volume flux varied from 0.8 to 1.0 m 3 /m 2 d.

Modification of the properties of rod-type membranes by varying typical parameters of the casting process for phase inversion membranes: A comparative study

Abstract The objective of the study was to modify the properties of polymer rodtype membranes. The membranes were cast from polysulfone, poly(vinyl chloride) and polyacrylonitrile by varying the phase inversion parameters (polymer concentration in the casting solution and solvent concentration in the gelation bath) and the parameters of motion of the system for mechanical casting of membranes. The properties of the membranes were tested with respect to three organic dyes of various molecular weights. The decrease of polymer concentration in the casting solution accounts for a distinct improvement of permeability in each of the three membranes and an insignificant deterioration of separation properties with respect to high molecular weight dyes (over 600). Addition of dimethylformamide to the gelation bath increases both permeability and selectivity of all membranes tested. Membranes gelated in 1.5 wt.% of dimethylformamide solution are found to be best suited for the separation of organic dyes by ultrafiltration.