ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Characterization and filtration performance of coating-modified polymeric membranes used in membrane bioreactors

Jozef Kochan, Thomas Wintgens, Thomas Melin, and John Erik Wong

Aachener Verfahrenstechnik, Lehrstuhl für Chemische Verfahrenstechnik, RWTH Aachen University, Turmstr. 46, 52056 Aachen, Germany

E-mail: jozef.kochan@avt.rwth-aachen.de

Received: 9 June 2008  Revised: 16 September 2008  Accepted: 23 September 2008

Abstract: One of the critical issues for membrane application in wastewater treatment is membrane fouling majorly caused by dissolved organic matters. The aim of the present study was to lower membrane fouling by adsorption of polyelectrolytes. In the paper, the feasibility of coating for diverse ultrafiltration membrane materials was investigated and their filtration performance was compared to that of the unmodified ones. Different ultrafiltration flat-sheet membranes, polyvinylidene fluoride, polyethersulfone, polysulfone and cellulose acetate were coated by branched poly(ethyleneimine) (PEI), poly(diallyldimethylammonium chloride) (PDADMAC) and poly(allylamine chloride) (PAH) and filtrated with sludge supernatant. Short term experiments showed a substantial drop of permeability: almost 40 % for PEI, 23 % for PDADMAC, and about 19 % for PAH coating. This deterioration resulted from the additional resistance of the deposited layers. On the other hand, coating led to lower fouling rates during filtration. In the stable state of filtration, coated membranes showed higher permeabilities compared to the uncoated ones. For the polyethersulfone membrane, the average permeability enhancement was 11 %. For polysulfone and cellulose acetate membranes, the permeability improved by 28 % and 15 % respectively. For polyvinylidene fluoride membranes only coating with PDADMAC enhanced the permeability, by 13 %. PEI and PAH modified membranes featured lower permeabilities than the uncoated ones.

Keywords: ultrafiltration membranes - surface modification - polyelectrolytes - coating - permeability

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0096-x

Chemical Papers 63 (2) 152–157 (2009)