Influence of ion size and charge in nanofiltration

Schaep, Johan; Bruggen, Bart Van der; Vandecasteele, Carlo; Wilms, D.

doi:10.1016/s1383-5866(98)00070-7

Cited by 497 publications

(254 citation statements)

References 14 publications

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“…The retention sequence of the salt solutions was R(Na 2 SO 4 )4R(NaCl)4R(MgSO 4 )4R(MgCl 2 ), which could be explained by the Donnan exclusion theory, which determines the retention performance of charged NF membranes. 78 Based on this theory, the Donnan potential at the interphase of the solution and membrane excludes co-ions from the membrane. To maintain electroneutrality of the solution on each side of the membrane, counter ions must also be excluded.…”

Section: Multilayer Graphene Desalination Membranesmentioning

confidence: 99%

Graphene membranes for water desalination

2017

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Extensive environmental pollution caused by worldwide industrialization and population growth has led to a water shortage. This problem lowers the quality of human life and wastes a large amount of money worldwide each year due to the related consequences. One main solution for this challenge is water purification. State-of-the-art water purification necessitates the implementation of novel materials and technologies that are cost and energy efficient. In this regard, graphene nanomaterials, with their unique physicochemical properties, are an optimum choice. These materials offer extraordinarily high surface area, mechanical durability, atomic thickness, nanosized pores and reactivity toward polar and non-polar water pollutants. These characteristics impart high selectivity and water permeability, and thus provide excellent water purification efficiency. This review introduces the potential of graphene membranes for water desalination. Although literature reviews have mostly concerned graphene's capability for the adsorption and photocatalysis of water pollutants, updated knowledge related to its sieving properties is quite limited. NPG Asia Materials (2017) 9, e427; doi:10.1038/am.2017.135; published online 25 August 2017 INTRODUCTION Currently,~1.2 billion people around the world are suffering from a shortage of water and its adverse consequences on health, food and energy. 1,2 On one hand, population growth, increased industrialization and greater energy needs and, on the other hand, loss of snowmelt, shrinkage of glaciers and so on will worsen this situation in upcoming years. As estimated by the world water council, the number of affected people will rise to 3.9 billion in the coming decades. 2,3 One of the most promising approaches to alleviate the water shortage, desalination can increase the water supply beyond what is available from the hydrological cycle. 4 Seawater desalination indeed provides an infinite, steady supply of high-quality water that does not harm natural freshwater ecosystems.Seawater comprises a vast supply of water (97.5% of all water on the planet). Thus, the growth of the installation of seawater desalination facilities in the past decade to circumvent water shortage problems in water-stressed countries has progressed quickly. In 2016, the global water production by desalination was estimated to be 38 billion cubic meter per year, that is, two times higher than that in 2008. 5 So far, seawater desalination has been mainly performed via multistage flash distillation and reverse osmosis (RO). 6 Mostly in the arid Persian Gulf countries, desalination plants perform based on heating and then condensing seawater. This kind of desalination plant consumes large amounts of thermal and electric energy, thus emitting greenhouse gases extensively. 7 In addition to this non-economical and non-ecofriendly version of desalination plants, the main type of desalination plants constructed in the past two decades, as well as future planned ones, are based on RO technology (Figure 1). 8

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Section: Multilayer Graphene Desalination Membranesmentioning

confidence: 99%

Graphene membranes for water desalination

2017

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“…This information is very important for many industrial applications, especially for those involving separation of mono/ divalent salts from small molecular weight organics. Table 4 shows the effect of glutaraldehyde MgSO 4 compared to those of NaCl, we calculated the theoretical rejections of Na + ,M g 2 + ,C l − and SO 4 2 − ions using their hydrated ionic radii [16] and Ferry's modified equation [12] for a pore of 1-nm radius. The corresponding calculated rejections were 49, 59, 41 and 50%.…”

Section: Permeation Of Model Solutesmentioning

confidence: 99%

Effects of surface crosslinking on sieving characteristics of chitosan/poly(acrylonitrile) composite nanofiltration membranes

Musale

Kumar

2000

Separation and Purification Technology

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Effects of surface crosslinking of chitosan/poly(acrylonitrile) (PAN) composite nanofiltration membranes at different crosslinker (glutaraldehyde) concentrations and crosslinking times on their surface chemical composition and sieving properties such as pure water permeation, molecular weight cut-off and the rejection of mono/divalent salts and mono/oligosaccharides were investigated. Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATRS) and X-ray photoelectron spectroscopy (XPS) studies revealed the crosslinking of chitosan with glutaraldehyde as well as variations in chemical composition with glutaraldehyde concentration and crosslinking time. Pure water permeation/swelling in water decreased and rejection of salts and sugars increased with increasing glutaraldehyde concentration, indicating pore contraction and increase in hydrophobicity as well as pore tortuosity due to crosslinking. Molecular weight cut-offs of surface crosslinked membranes were in the range of 550 -700 Da, a characteristic of nanofiltration membranes, whereas uncrosslinked membrane had cut-off of \ 1500 Da. The crosslinked membranes were found to be stable over 10-h operation for pure water permeation and the stability increased with increasing glutaraldehyde concentration.

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“…3. Similar to the case of methyl-, the charge of carboxyl-terminated ligands is negative as demonstrated by a rejection in the order of R(MgCl 2 )oR(NaCl)oR(Na 2 SO 4 ) 30 . While in the case of methyl, charge is due to OH À adsorption, carboxyl is inherently negative under identical electrolyte conditions due to deprotonation and |X| can be as much as two to three times larger for a given set of ions (Fig.…”

Section: Resultsmentioning

confidence: 85%

Ion transport controlled by nanoparticle-functionalized membranes

et al. 2014

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From proton exchange membranes in fuel cells to ion channels in biological membranes, the well-specified control of ionic interactions in confined geometries profoundly influences the transport and selectivity of porous materials. Here we outline a versatile new approach to control a membrane's electrostatic interactions with ions by depositing ligand-coated nanoparticles around the pore entrances. Leveraging the flexibility and control by which ligated nanoparticles can be synthesized, we demonstrate how ligand terminal groups such as methyl, carboxyl and amine can be used to tune the membrane charge density and control ion transport. Further functionality, exploiting the ligands as binding sites, is demonstrated for sulfonate groups resulting in an enhancement of the membrane charge density. We then extend these results to smaller dimensions by systematically varying the underlying pore diameter. As a whole, these results outline a previously unexplored method for the nanoparticle functionalization of membranes using ligated nanoparticles to control ion transport.

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Influence of ion size and charge in nanofiltration

Cited by 497 publications

References 14 publications

Graphene membranes for water desalination

Graphene membranes for water desalination

Effects of surface crosslinking on sieving characteristics of chitosan/poly(acrylonitrile) composite nanofiltration membranes

Ion transport controlled by nanoparticle-functionalized membranes

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