Effect of grafting on microstructure, composition and surface and transport properties of ceramic membranes for osmotic evaporation

Vargas-Garcia, Armando; Torrestiana-Sánchez, Beatriz; Garcı́a-Bórquez, A.; Aguilar‐Uscanga, María Guadalupe

doi:10.1016/j.seppur.2011.05.030

Cited by 15 publications

(5 citation statements)

References 38 publications

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“…For instance, tethered polymer chains or brushes in Micro-Electro-Mechanical systems (MEMS) or membrane technologies have attracted great attention due to their potential for flow regulation [1][2][3] . As another example, the combination of traditional ceramic membranes and organic polymers yields diverse surface properties, extending its usage to a wide range of solvents 4 . In addition to regulating the wettability, the polymer grafting can realize pore size tuning at the same time, which makes ceramic membranes more versatile 5 .…”

Section: Introductionmentioning

confidence: 99%

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Wang

et al. 2019

Soft Matter

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We develop an efficient parallel multiscale method that bridges the atomistic and mesoscale regimes, from nanometer to micron and beyond, via concurrent coupling of atomistic simulation and mesoscopic dynamics. In particular, we combine an all-atom molecular dynamics (MD) description for specific atomistic details in the vicinity of the functional surface, with a dissipative particle dynamics (DPD) approach that captures mesoscopic hydrodynamics in the domain away from the functional surface. In order to achieve a seamless transition in dynamic properties we endow the MD simulation with a DPD thermostat, which is validated against experimental results by modeling water at different temperatures. We then validate the MD-DPD coupling method for transient Couette and Poiseuille flows, demonstrating that the concurrent MD-DPD coupling can resolve accurately the continuum-based analytical solutions. Subsequently, we simulate shear flows over polydimethylsiloxane (PDMS)-grafted surfaces (polymer brushes) for various grafting densities, and investigate the slip flow as a function of the shear stress. We verify that a "universal" power law exists for the sliplength, in agreement with published results. Having validated the MD-DPD coupling method, we simulate time-dependent flows past an endothelial glycocalyx layer (EGL) in a microchannel. Coupled simulation results elucidate the dynamics of EGL changing from an equilibrium state to a compressed state under shear by aligning the molecular structures along the shear direction. MD-DPD simulation results agree well with results of a single MD simulation, but with the former more than two orders of magnitude faster than the latter for system sizes above one micron. * The first two authors contribute equally to this work.

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Section: Introductionmentioning

confidence: 99%

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Wang

et al. 2019

Soft Matter

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“…Debye length (λ) can be obtained by Eq. 3 51 .where, e is the electron charge, is the ionic strength of solution, n i is the number concentration of ion i in solution, z i is valence of ion i , is the permittivity of the solution, k is Boltzmann’s constant, and T is temperature. It can be seen that Debye length (λ) is inversely proportional to the square root of ionic strength of solution.…”

Section: Resultsmentioning

confidence: 99%

Surface modification of polyvinylidene fluoride (PVDF) membrane via radiation grafting: novel mechanisms underlying the interesting enhanced membrane performance

Shen

Feng

Li³

et al. 2017

Sci Rep

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This study provided the first attempt of grafting hydrophobic polyvinylidene fluoride (PVDF) membrane with hydrophilic hydroxyethyl acrylate (HEA) monomer via a radiation grafting method. This grafted membrane showed an enhanced hydrophilicity (10° decrease of water contact angle), water content ratio, settling ability and wettability compared to the control membrane. Interestingly, filtration tests showed an improved dependence of water flux of the grafted membrane on the solution pH in the acidic stage. Atomic force microscopy (AFM) analysis provided in-situ evidence that the reduced surface pore size of the grafted membrane with the solution pH governed such a dependence. It was proposed that, the reduced surface pore size was caused by the swelling of the grafted chain matrix, with the pH increase due to the chemical potential change. It was found that the grafted membrane showed a lower relative flux decreasing rate than the control membrane. Moreover, flux of the bovine serum albumin (BSA) solution was noticeably larger than that of pure water for the grafted membrane. Higher BSA flux than water flux can be explained by the effects of electric double layer compression on the polymeric swelling. This study not only provided a pH-sensitive PVDF membrane potentially useful for various applications, but also proposed novel mechanisms underlying the enhanced performance of the grafted membrane.

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“…The wettability of even a small fragment of the membrane wall causes the salts to penetrate from the stripping solution into the feed which deteriorates its quality and, as a result, can eliminate the possibility, e.g., juice concentration. Usually, the electrical conductivity of the juice is monitored to ensure the membrane integrity and hydrophobicity, and any salt leakage through the membrane was confirmed in several works (Bui and Nguyen 2005 ; Cissé et al 2011 ; Vargas-Garcia et al 2011 ; Zambra et al 2015 ). However, these results were obtained during short periods of measurements (below 50 h); therefore, a significantly longer period (2.5 years) was used in this work for evaluation of membrane resistance for salt leakage.…”

Section: Introductionmentioning

confidence: 94%

“…The osmotic membrane distillation (OMD) is a low-temperature method for solution concentration by water evaporation. In this process both sides of a porous hydrophobic membrane are in contact with two aqueous solutions (feed and striping solution—usually brine) (Bui and Nguyen 2005 ; Vargas-Garcia et al 2011 ). The hydrophobic property of the used membrane prevents a penetration of separated solutions into the membrane pores and the pores are filled only by the gas phase (Goh et al 2013 ; Zambra et al 2015 ).…”

Section: Introductionmentioning

confidence: 99%

The long-term studies of osmotic membrane distillation

Gryta

2017

Chem. Pap.

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The results of osmotic membrane distillation carried out for 2.5 years were presented in this work. The influence of the process conditions, such as temperature and brine concentration on the permeate flux, was investigated. The saturated NaCl solutions and distilled water were used as a stripping solution and feed, respectively. A continuous regeneration of stripping solution was conducted using a method of natural evaporation from the surface of Białecki rings to the air surrounding the installation. The possibilities of application of Accurel PP S6/2 hydrophobic polypropylene membranes were tested. It was studied whether a saturation stripping solution does not cause scaling and wettability of membranes. It was found that most of the pores in the used membranes were non-wetted, and the salt retention over 99% was maintained during a study period. However, the obtained permeate flux was decreased by 10–20%. The SEM examinations revealed that it was caused by amorphous deposit, which was formed on the membrane surface on the brine side. The SEM–EDS analysis demonstrated that the deposit composition mainly included Si and O.Electronic supplementary materialThe online version of this article (doi:10.1007/s11696-017-0261-1) contains supplementary material, which is available to authorized users.

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Effect of grafting on microstructure, composition and surface and transport properties of ceramic membranes for osmotic evaporation

Cited by 15 publications

References 38 publications

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Concurrent coupling of atomistic simulation and mesoscopic hydrodynamics for flows over soft multi-functional surfaces

Surface modification of polyvinylidene fluoride (PVDF) membrane via radiation grafting: novel mechanisms underlying the interesting enhanced membrane performance

The long-term studies of osmotic membrane distillation

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