Effects of water chemistry on structure and performance of polyamide composite membranes

Wang, Jinwen; Mo, Yibing; Mahendra, Shaily; Hoek, Eric M.V.

doi:10.1016/j.memsci.2013.09.022

Cited by 49 publications

(25 citation statements)

References 46 publications

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“…The solute-membrane partition coefficient, ϕ s , as defined here (Equation 5), accounts for all of these factors, whereas all the other parameters described above account for either physical or chemical interactions. The correlation coefficients between R and ϕ s were all very strong (−0.965 to −0.996) (Figure 2e), which is consistent with our prior results (Verliefde, 2009;Wang, Mo, Mahendra, & Hoek, 2014) and suggests that this approach offers a fairly robust framework for understanding uncharged, organic solute rejection by NF and RO membranes.…”

Section: Rejection Mechanisms Of Uncharged Organic Solutes By Nf Ansupporting

confidence: 88%

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How permeable could a reverse osmosis membrane be if it was specifically developed for uncharged organic solute rejection?

Wang

McVerry

et al. 2020

AWWA Water Science

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Here, we present both experimental data and modeling results of the removal of four different polar organic solutes by six different commercial nanofiltration (NF) and reverse osmosis (RO) membranes in a natural groundwater matrix. These results are significant for two reasons. First, three of the polar organic solutes are contaminants commonly found in both drinking water aquifers and municipal wastewaters and, hence, are particularly relevant to the protection of public health in drinking water production and potable reuse applications. Second, our membrane transport model can be used (1) to understand the fundamental mechanism governing uncharged, polar organic solute rejection and (2) to make forward predictions about how one might alter NF/RO membrane chemistry and structure to achieve a desired level of rejection. Perhaps a disappointing conclusion is that, for uncharged, polar organic solutes, the only obvious means of improving rejection is to reduce pore size, increase barrier layer thickness, and/or decrease barrier layer porosity, all of which reduce water permeability and energy efficiency. However disappointing this conclusion may be, we believe the fundamental insights that can be derived from this work are significant and important for the drinking water and water reuse scientific communities.

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Section: Rejection Mechanisms Of Uncharged Organic Solutes By Nf Ansupporting

confidence: 88%

“…Combining 1aand 1balong with the definition of the concentration polarization factor (β = Cm/Cb, where Cm and Cb are the membrane surface and bulk feed solute concentrations) gives the following explicit equation for observed solute rejection (R) (Wang et al, 2014):…”

Section: Membrane Structure and Solutemembrane Interaction Charactementioning

confidence: 99%

How permeable could a reverse osmosis membrane be if it was specifically developed for uncharged organic solute rejection?

Wang

McVerry

et al. 2020

AWWA Water Science

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“…This model initially developed for nonporous Figure 1: Extraction of the hydraulic permeabilities of different zeolite tubular membranes from the representation of the permeation flux versus the transmembrane pressure (membranes 1 (dotted lines) and 5 (full lines) before (black) and after the alkaline treatment (grey)). membrane has been modified to describe the transfer of water through NF/RO porous membranes [27].…”

Section: Resultsmentioning

confidence: 99%

Hydraulic Performance Modifications of a Zeolite Membrane after an Alkaline Treatment: Contribution of Polar and Apolar Surface Tension Components

Dutournié

Said

Daou

et al. 2015

Advances in Materials Science and Engineering

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Hydraulic permeability measurements are performed on low cut-off Na-mordenite (MOR-type zeolites) membranes after a mild alkaline treatment. A decrease of the hydraulic permeability is systematically observed. Contact angle measurements are carried out (with three polar liquids) on Na-mordenite films seeded onto alumina plates (flat membranes). A decrease of the contact angles is observed after the alkaline treatment for the three liquids. According to the theory of Lifshitz-van der Waals interactions in condensated state, surface modifications are investigated and a variation of the polar component of the material surface tension is observed. After the alkaline treatment, the electron-donor contribution (mainly due to the two remaining lone electron pairs of the oxygen atoms present in the zeolite extra frameworks) decreases and an increase of the electron-receptor contribution is observed and quantified. The contribution of the polar component to the surface tension is attributed to the presence of surface defaults, which increase the surface hydrophilicity. The estimated modifications of the surface interaction energy between the solvent (water) and the Na-mordenite active layer are in good agreement with the decrease of the hydraulic permeability observed after a mild alkaline treatment.

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“…An analysis of the effect of feed solution chemistry on the permeability of reverse osmosis membranes [43] revealed that permeability decreased with increasing ionic strength. Since the draw solution must be of higher concentration than the feed water, and thus typically of higher ionic strength, this suggests that RO regeneration is at a disadvantage compared to direct reverse osmosis treatment of the feed; at least if the draw solution is ionic.…”

Section: An Analysis Of Ro As a Regeneration Process For Fomentioning

confidence: 99%

On the potential of forward osmosis to energetically outperform reverse osmosis desalination

McGovern

Lienhard

2014

Journal of Membrane Science

221

116

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We provide a comparison of the theoretical and actual energy requirements of forward osmosis and reverse osmosis seawater desalination. We argue that reverse osmosis is significantly more energy efficient and that forward osmosis research efforts would best be fully oriented towards alternate applications. The underlying reason for the inefficiency of forward osmosis is the draw-dilution step, which increases the theoretical and actual energy requirements for draw regeneration. As a consequence, for a forward osmosis technology to compete with reverse osmosis, the regeneration process must be significantly more efficient than reverse osmosis. However, even considering the optimisation of the draw solution and the benefits of reduced fouling during regeneration, the efficiency of an optimal draw regeneration process and of reverse osmosis are unlikely to differ significantly, meaning the energy efficiency of direct desalination with reverse osmosis is likely to be superior.

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Effects of water chemistry on structure and performance of polyamide composite membranes

Cited by 49 publications

References 46 publications

How permeable could a reverse osmosis membrane be if it was specifically developed for uncharged organic solute rejection?

How permeable could a reverse osmosis membrane be if it was specifically developed for uncharged organic solute rejection?

Hydraulic Performance Modifications of a Zeolite Membrane after an Alkaline Treatment: Contribution of Polar and Apolar Surface Tension Components

On the potential of forward osmosis to energetically outperform reverse osmosis desalination

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