Modeling of the Adsorption of Organic Compounds on Polymeric Nanofiltration Membranes in Solutions Containing Two Compounds

Braeken, Leen; Boussu, Katleen; Bruggen, Bart Van der; Vandecasteele, Carlo

doi:10.1002/cphc.200400624

Cited by 41 publications

(21 citation statements)

References 49 publications

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“…This shows the close relationship between adsorption phenomena and retention of micropollutants. Several models to predict the amount adsorbed on a membrane for mixtures based on the amount adsorbed with only one compound have also been developed [101].…”

Section: Micropollutant Transport Models For Membrane Filtrationmentioning

confidence: 99%

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

Schäfer

Akanyeti

Semiao

2011

Advances in Colloid and Interface Science

249

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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Section: Micropollutant Transport Models For Membrane Filtrationmentioning

confidence: 99%

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

Schäfer

Akanyeti

Semiao

2011

Advances in Colloid and Interface Science

249

140

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“…[3] Adsorption, on the other hand, is dependent on the solution chemistry and on both membrane and surfactant properties. [4][5][6][7][8] In the case of nonionic surfactants, a more hydrophobic membrane surface and/or surfactant gives rise to more adsorption and hence to more membrane fouling. In the case of ionic surfactants, not only the hydrophobicity but also the charge of the membrane and of the surfactant are important characteristics to explain the adsorbed amount and membrane fouling.…”

Section: Introductionmentioning

confidence: 99%

“…This is explained in the literature by increased hydrophobicity of nonionic surfactants in the presence of salts. [9] As it is commonly accepted that more adsorption occurs for more hydrophobic compounds, [5] the adsorbed amount of neodol in the presence of salt is indeed larger. Hydrophobic interactions between neodol and the membrane surface of NFPES10 cause the hydrophilic heads of neodol to be oriented towards the aqueous phase, and this results in a more hydrophilic membrane surface (Table 4).…”

mentioning

confidence: 99%

“…From the concentration difference between the batch cell with membrane and the batch cell without membrane (blank), the adsorbed amount per unit area of membrane (mmol m À2 ) could be determined. [5] In all experiments a feed solution of 600 mg L À1 (with or without NaCl and at different pH values) was used to obtain significant adsorption. The absolute fault in the adsorbed amount, calculated by fault analysis, ranges between 2-4 mmol m À2 .…”

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confidence: 99%

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Surfactant Fouling of Nanofiltration Membranes: Measurements and Mechanisms

et al. 2007

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Fouling of nanofiltration membranes is studied during filtration of aqueous surfactant solutions under different conditions. To this purpose, four typical nanofiltration membranes (Desal51HL, NF270, NTR7450 and NFPES10) and three typical surfactants (nonionic neodol, anionic SDBS and cationic cetrimide) are selected. Fouling is studied as a function of the surfactant concentration, with and without addition of an electrolyte (NaCl), at different pH and when filtering a mixture of surfactants. Adsorption experiments and hydrophobicity measurements (to study the orientation of the surfactants on the membrane surface) are also performed under the different conditions. The least membrane fouling is found for the anionic surfactant SDBS, while for the cationic surfactant cetrimide very low relative fluxes are observed. Neodol shows an intermediate degree of fouling. Both hydrophobic and electrostatic interactions (in the case of ionic surfactants) between the membrane surface and the surfactant explain the degree of adsorption and hence fouling, as membrane fouling is correlated with the amount of adsorbed surfactant. The difference between cetrimide and SDBS becomes especially visible when changing the pH: increasing the pH leads not only to an opposite orientation of the adsorbed surfactants, but also to an opposite trend in adsorbed amount and membrane fouling. This study permits selection of an optimal nanofiltration membrane to recycle wastewater containing surfactants in the carwash industry. The optimal choice would be a hydrophilic membrane with a low molecular weight cut-off and a small negative surface charge at neutral pH. Cationic surfactants in the wastewater should also be avoided as much as possible.

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“…4,5 Adsorbed molecules increase the hydrophobicity of the membrane or may decrease the pore diameter, leading to a decline of water permeability. 6 One of the methods proposed in the recent literature to avoid membrane fouling is the use of hydrophilic particles as additives to the membrane compositions. Due to the hydrophilic nature of additives immersed in the membrane structure, the undesired hydrophobic interactions that take place between organic foulants and the membrane surface can be reduced considerably.…”

Section: 3mentioning

confidence: 99%

Binary metal oxides for composite ultrafiltration membranes

et al. 2014

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A new ultrafiltration membrane was developed by the incorporation of binary metal oxides of the type Ti (x) Zr (1Àx) O 2 inside polyethersulfone. Physico-chemical characterization of the binary metal oxides demonstrated that the presence of Ti in the TiO 2 -ZrO 2 system results in an increase of the size of the oxides, and also their dispersity. The crystalline phases of the synthesized binary metal oxides were identified as srilankite and zirconium titanium oxide. The effect of the addition of ZrO 2 can be expressed in terms of the inhibition of crystal growth of nanocrystalline TiO 2 during the synthesis process. For photocatalytic applications the band gap of the synthesized semiconductors was determined, confirming a gradual increase (blue shift) in the band gap as the amount of Zr loading increases. Distinct distributions of binary metal oxides were found along the permeation axis for the synthesized membranes. Particles with Ti are more uniformly dispersed throughout the membrane cross-section.The physico-chemical characterization of membranes showed a strong correlation between some key membrane properties and the spatial particle distribution in the membrane structure. The proximity of metal oxide fillers to the membrane surface determines the hydrophilicity and porosity of modified membranes. Membranes incorporating binary metal oxides were found to be promising candidates for wastewater treatment by ultrafiltration, considering the observed improvement in flux and anti-fouling properties of doped membranes. Multi-run fouling tests of doped membranes confirmed the stability of permeation through membranes embedded with binary TiO 2 -ZrO 2 particles.

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Modeling of the Adsorption of Organic Compounds on Polymeric Nanofiltration Membranes in Solutions Containing Two Compounds

Cited by 41 publications

References 49 publications

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

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

Surfactant Fouling of Nanofiltration Membranes: Measurements and Mechanisms

Binary metal oxides for composite ultrafiltration membranes

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