Structure and dynamics of water confined in a polyamide reverse-osmosis membrane: A molecular-simulation study

Ding, Minxia; Szymczyk, Anthony; Goujon, Florent; Soldera, Armand; Ghoufi, Aziz

doi:10.1016/j.memsci.2014.01.054

Cited by 128 publications

(119 citation statements)

References 42 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…Cross-linked polyamide (PA) was generated by following the procedure developed in Refs. [23,24]. In the first stage of our construction protocol several linear chains of polyamide are packed into a simulation box according to a well-established method combining Monte Carlo (MC) and MD simulations.…”

Section: Models and Interactionsmentioning

confidence: 99%

“…Computational details of our construction are given in Refs. [23,24]. The simulation box is orthorhombic such that the box lengths according to the x and y directions are L x = L y = 37.3 Å while L z = 100 Å (the thickness of the polyamide membrane is about 100 Å).…”

Section: Models and Interactionsmentioning

confidence: 99%

“…Although MD has been already applied to investigate both water and ion transports through nanopores with well-defined geometries [12][13][14][15][16][17][18], the limited information about the three-dimensional molecular structure of RO polyamide membranes makes the use of this computational method much more challenging. As a result, the identification and the understanding at a microscopic level of the underlying mechanisms governing water and ion transport through RO membranes are proceeding very slowly and only few studies reported on the attempt of building full atomistic models of RO polyamide membranes [19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…In this work we apply a recent approach proposed by our group for building atomistic models of RO polyamide membranes [23,24] in order to investigate both ion and water transport from pressure-driven molecular dynamics simulations.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the structure and rejection of ions by a polyamide membrane in pressure-driven molecular dynamics simulations

2015

Self Cite

View full text Add to dashboard Cite

Section: Models and Interactionsmentioning

confidence: 99%

Section: Models and Interactionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the structure and rejection of ions by a polyamide membrane in pressure-driven molecular dynamics simulations

2015

Self Cite

View full text Add to dashboard Cite

“…investigated the behaviour of water in all-silica 1-D pore zeolites and their use as desalination membranes by employing quantum mechanical and molecular dynamics calculations, and found higher self-diffusivities than those obtained from conventional polyamide membranes (ca. 0.2 × 10 −9 m 2 s −1 ) (Ding et al, 2014b. In addition, it was shown that the penetration of Cl − into the framework was energetically unfavourable.…”

Section: Introductionmentioning

confidence: 99%

A computational approach to evaluation of nanoporous zeolitic membranes for reverse osmosis desalination

Han¹

View full text Add to dashboard Cite

Water scarcity has become one of the major global concerns. Research has shown that more than one-third of the population throughout the world resides in water-stressed regions now.Reverse osmosis (RO) desalination has recently been highlighted as a clean technology that is less energy intensive using membranes rather than directly consuming fossil fuels.Advances in nanomaterials have opened new possibilities for RO membrane materials. Zeolites are one of the candidate materials due to their crystalline structures and durability. However, the performance of zeolite membranes has not been successful for practical use due to poor water flux.Thus, we used molecular dynamics simulations to investigate, at the molecular level, a series of potential zeolite types which have been rarely studied for application in desalination. We determine diffusion coefficients and the structure of water when it passes through pores of these zeolites. In addition, we examine the potential of mean force for water or ions as they move into and through a zeolite membrane in order to evaluate how favourable the passage of the molecule of interest through each membrane is. This provided us with some criteria (i.e. water permeability and ion selectivity) to judge if the membrane is likely to have suitable desalination performance. Without this molecular-level understanding, selection of zeolite materials for desalination membranes is difficult.Some widely-studied types and potential types of zeolites were selected for our study. The common types have all 3-dimensional (3-D) pore structures, while the potential zeolites have 1-dimensional (1-D) cylindrical pores. To investigate the water dynamics and structure in these different pores, we employed molecular (MD) dynamics simulations. The MD results showed the water self-diffusivity, which indicates a molecular mobility, in the 1-D pores is up to 18-time higher than that of the 3-D pores. As it was found that water molecules formed clusters, water droplets, and moved collectively at low water density in the zeolite pores, the water collective diffusivity, which is directly related to water flux, was also measured for the all the case of zeolites. This collective diffusivity through the 1-D pore zeolites was around one order of magnitude higher than that of the 3-D pore zeolites, suggesting our 1-D zeolites selected are promising as high flux membranes.To evaluate the thermodynamic stability for water or ion of interest when they pass across the zeolite membranes, the potential of mean force calculations were carried out using MD simulations.We selected one of the 3-D pore zeolites (LTA) and another of the 1-D pore zeolites (VET) for the membrane. In general, these membranes had a moderate energy barrier to water transport, but a very high barrier to sodium or chloride ion transport except the VET membrane. The chloride ion ii had a minimum in the potential of mean force at the pore entrance and a preference for the chloride ion to enter the pore than to enter the bulk solution for the...

show abstract

Neutron Reflectivity and Performance of Polyamide Nanofilms for Water Desalination

Foglia

Karan

Nania

et al. 2017

Adv Funct Materials

View full text Add to dashboard Cite

The structure and hydration of polyamide (PA) membranes are investigated with a combination of neutron and X-ray reflectivity, and their performance is benchmarked in reverse osmosis water desalination. PA membranes are synthesized by the interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), varying systematically reaction time, concentration, and stoichiometry, to yield large-area exceptionally planar films of ≈10 nm thickness. Reflectivity is employed to precisely determine membrane thickness and roughness, as well as the (TMC/MPD) concentration profile, and response to hydration in the vapor phase. PA film thickness is found to increase linearly with reaction time, albeit with a nonzero intercept, and the composition cross-sectional profile is found to be uniform, at the conditions investigated. Vapor hydration with H2O and D2O from 0 to 100% relative humidity results in considerable swelling (up to 20%), but also yields uniform cross-sectional profiles. The resulting film thickness is found to be predominantly set by the MPD concentration, while TMC regulates water uptake. A favorable correlation is found between higher swelling and water uptake with permeance. The data provide quantitative insight into the film formation mechanisms and correlate reaction conditions, cross-sectional nanostructure, and performance of the PA active layer in RO membranes for desalination

show abstract

Structure and dynamics of water confined in a polyamide reverse-osmosis membrane: A molecular-simulation study

Cited by 128 publications

References 42 publications

On the structure and rejection of ions by a polyamide membrane in pressure-driven molecular dynamics simulations

On the structure and rejection of ions by a polyamide membrane in pressure-driven molecular dynamics simulations

A computational approach to evaluation of nanoporous zeolitic membranes for reverse osmosis desalination

Neutron Reflectivity and Performance of Polyamide Nanofilms for Water Desalination

Contact Info

Product

Resources

About