Organic compounds passage through RO membranes

Libotean, Dan; Giralt, Jaume; Ralló, Robert; Cohen, Yoram; Giralt, Francesc; Ridgway, Harry F.; Rodriguez, Grisel; Phipps, Don

doi:10.1016/j.memsci.2007.11.052

Cited by 40 publications

(24 citation statements)

References 43 publications

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“…2D and Fig. 2C) have indeed been confirmed for micropollutants by various polymeric membranes [23,[25][26][27][28]30,[32][33][34]36,40,56,68,[78][79][80][81][82][83]. Nghiem and Schäfer [25] have measured such a breakthrough curve for estrogens at 100 ng/L using a technique with radiolabelled micropollutants.…”

Section: Retention Of Micropollutants By Polymeric Membranesmentioning

confidence: 72%

“…Other characteristics considered have been molecular shape and size [31][32][33][34]. Van der Bruggen et al [31] showed that molecular weight (MW) is a good indicator of NF and RO retention compared to other molecular sizes such as Stokes diameter.…”

Section: Micropollutant Characteristics: the Group Of Estrogensmentioning

confidence: 99%

“…Van der Bruggen et al [31] showed that molecular weight (MW) is a good indicator of NF and RO retention compared to other molecular sizes such as Stokes diameter. In general, the bigger the molecular size, the higher the retention [31][32][33]. Kiso et al [35] obtained a clear increase of retention with increase of molecular size (such as molecular width, molecular mean size, and molecular weight) for alcohols and saccharides.…”

Section: Micropollutant Characteristics: the Group Of Estrogensmentioning

confidence: 99%

“…The principal component analysis method (quantitative structure relations or QSR) has been developed to obtain a model that describes retention as a function of the contaminants' most important variables (e.g. molecular width and depth) by nanofiltration membranes [55,56] and the NF membrane characteristics such as roughness or active layer thickness [32]. Limitations of such models are the validity for certain boundary conditions only, and while simple in nature, they cannot replace the understanding of fundamental mechanisms.…”

Section: Micropollutant Transport Models For Membrane Filtrationmentioning

confidence: 99%

“…Nanofiltration (NF) and reverse osmosis (RO) are the most suitable membrane processes for micropollutant control while more porous processes such as microfiltration (MF) and ultrafiltration (UF) cannot retain such small molecules. However, NF and RO removal of micropollutants is reported as erratic and not predictable from molecular weight of micropollutants [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

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Micropollutant sorption to membrane polymers: A review of mechanisms for estrogens

Schäfer

Akanyeti

Semiao

2011

Advances in Colloid and Interface Science

245

140

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Organic micropollutants such as estrogens occur in water in increasing quantities from predominantly anthropogenic sources. In water such micropollutants partition not only to surfaces such as membrane polymers but also to any other natural or treatment related surfaces. Such interactions are often observed as sorption in treatment processes and this phenomenon is exploited in activated carbon filtration, for example. Sorption is important for polymeric materials and this is used for the concentration of such micropollutants for analytical purposes in solid phase extraction. In membrane filtration the mechanism of micropollutant sorption is a relatively new discovery that was facilitated through new analytical techniques. This sorption plays an important role in micropollutant retention by membranes although mechanisms of interaction are to date not understood. This review is focused on sorption of estrogens on polymeric surfaces, specifically membrane polymers. Such sorption has been observed to a large extent with values of up to 1.2 ng/cm(2) measured. Sorption is dependent on the type of polymer, micropollutant characteristics, solution chemistry, membrane operating conditions as well as membrane morphology. Likely contributors to sorption are the surface roughness as well as the microporosity of such polymers. While retention-and/or reflection coefficient as well as solute to effective pore size ratio-controls the access of such micropollutants to the inner surface, pore size, porosity and thickness as well as morphology or shape of inner voids determines the available area for sorption. The interaction mechanisms are governed, most likely, by hydrophobic as well as solvation effects and interplay of molecular and supramolecular interactions such as hydrogen bonding, π-cation/anion interactions, π-π stacking, ion-dipole and dipole-dipole interactions, the extent of which is naturally dependent on micropollutant and polymer characteristics. Systematic investigations are required to identify and quantify both relative contributions and strength of such interactions and develop suitable surface characterisation tools. This is a difficult endeavour given the complexity of systems, the possibility of several interactions taking place simultaneously and the generally weaker forces involved.

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