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

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.

Layer-by-Layer Deposition of Titanium Dioxide Nanoparticles on Polymeric Membranes: A Life Cycle Assessment Study

“…Input/output data of membrane manufacturing are not reported here, as this information is confidential (proprietary data of Pentair X-Flow). PES membrane is then modified by applying the LbL technique (Figure b), i.e., an alternating adsorption of oppositely charged polyions on a charged membrane surface to enable attachment of TiO 2 on it by electrostatic forces. − In this case study, the PES membrane was modified with a single layer of PE. In detail, a 0.05 M solution of poly(ethylenimine) (PEI; molecular weight = 750 000 g/mol, purchased from Sigma-Aldrich) was prepared in deionized water.…”

A critical review on advanced anaerobic membrane bioreactors (AnMBRs) for wastewater treatment: advanced membrane materials and energy demand

“…Kochan et al reported a study by coating polyethyleneimine (PEI), polyallylamine chloride (PAH) and polydiallyldimethylammonium chloride (PDADMAC) on the PVDF, PSF and PES membranes, and less fouling was observed. 61 The disadvantages of the coating technique include lower chemical stability and low physical tolerance. Therefore, to resolve the concerning issues, self-assembly techniques are utilized to manufacture thin-film composite (TFC) membranes.…”

Membrane bioreactors for water treatment

“…In AnMBRs, metallic membranes have also been applied because of their better hydraulic performance, better fouling recovery, and better tolerance to oxidation and high temperature (Kim & Jung, 2007;Zhang et al, 2005). Kochan, Wintgens, Melin, and Wong (2009) studied surface coating via the adsorption of surfactants in which different UF flat-sheet membranes were coated with branched poly(ethyleneimine), poly(diallyldimethyl ammonium chloride), and poly(allylamine chloride) and filtered with sludge supernatant. Typically, materials such as PVDF, PES, PE, and PP are applied with pore sizes in the MF or UF range (0.03e1 mm) and in hollow fibre, flat sheet, or tubular configurations.…”