Pervaporation of Alcohols and Methyl <i>t</i><i>ert</i>-Butyl Ether through a Dense Poly(2,6-dimethyl-1,4-phenylene oxide) Membrane

Heat treatment is believed to be an important step in controlling the morphology and properties of polymer based membranes. In this study, hybrid organic-inorganic membrane based on poly(vinyl alcohol) (PVA), maleic acid (MA) and tetraethyl orthosilicate (TEOS) was synthesised via a sol-gel route. The effects of heating temperature and heating time on pervaporation separation performance of aqueous salt solution were studied in relation to swelling and hydrophilic properties, the free volume, salt transport properties, and water diffusivity of the membrane. The free volume of the hybrid membrane under different heat treatment conditions were well correlated with the pervaporation testing results. With increasing heating temperature or time, the fractional free volume of the hybrid membrane was reduced due to a more compact structure by crosslinking among PVA, MA and TEOS. As a result, the water flux decreased and the salt rejection increased. The salt transport properties followed a similar trend as the water uptake, indicating the hydrated NaCl was solvated by water in the membrane phase.

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“…The apparent diffusion coefficient of water was calculated from the following equation based on Fick's law [18]:…”

Section: Pervaporation Testingmentioning

confidence: 99%

Effect of heat treatment on pervaporation separation of aqueous salt solution using hybrid PVA/MA/TEOS membrane

Xie

Hoang

et al. 2014

Separation and Purification Technology

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“…Based on Fick's law, the permeation flux of component i can be expressed as [9,16,17] For simplicity, the apparent diffusion coefficient can be calculated by the equation [17]:…”

Section: Pervaporation Testingmentioning

confidence: 99%

“…The PVA/MA/silica membrane containing 20 wt% MA and 10 wt% silica had a highest diffusion coefficient of 7.67 x10 -12 m 2 /s. It is known the diffusivity is generally dependent on both the size of the penetrant and the polymer structure [17]. As water has a very small molecular size (0.278 nm), the diffusion of water through membrane is more determined by the nanostructure of the membrane.…”

Section: Pervaporation Testingmentioning

confidence: 99%

Sol–gel derived poly(vinyl alcohol)/maleic acid/silica hybrid membrane for desalination by pervaporation

Xie

Hoang

Duong

et al. 2011

Journal of Membrane Science

134

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Highly dispersed homogeneous hybrid polymer-inorganic membranes based on poly(vinyl alcohol) (PVA), maleic acid (MA) and inorganic silica were synthesized via a sol-gel method. Tetraethoxy-silane (TEOS) was used as the silica precursor with MA as an additional crosslinking agent. A range of techniques such as FTIR, SEM, TGA, XRD and DSC were used to characterise the nanostructure and properties of hybrid membranes. Results revealed silica nanoparticles (<10 nm) were well dispersed in the polymer matrix with chemical bonding between the organic and inorganic phases. Thermal properties of the hybrid membranes were significantly enhanced when compared with pure PVA membranes, and swelling of PVA based hybrid membranes was greatly suppressed.The chemically crosslinked PVA with maleic acid and silica resulted in the formation of new hybrid membranes with improved pervaporation properties for desalination application. The pervaporation separation performance of aqueous salt solution was found to be directly related to the diffusion coefficient of water through hybrid PVA/MA/silica membranes. Introduction of MA and silica at given amounts into the polymer chain increased the amorphous region of the membrane and favoured the diffusion of water molecules through the membrane. A water flux of 6.93 kg/m 2 ·hr with salt rejection of >99.5% was achieved at a 6 Torr vacuum and 22°C.

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“…The apparent diffusion coefficient of water was calculated from a simplified equation derived from Fick's law [15]:…”

Section: Pervaporation Testingmentioning

confidence: 99%

Separation of aqueous salt solution by pervaporation through hybrid organic–inorganic membrane: Effect of operating conditions

et al. 2011

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Hybrid polymer-inorganic membranes were prepared by crosslinking poly(vinyl alcohol) (PVA), maleic acid (MA) and silica via an aqueous sol-gel route. Membrane characterisation results revealed silica nanoparticles (<10 nm) were well dispersed in the polymer matrix and significantly reduced swelling of the membrane. The membranes were tested for pervaporation separation of aqueous salt solution with NaCl concentrations of 0.2-5.0 wt% at temperatures 20-65°C, feed flowrates 30-150 mL/min and permeate pressures 2-40 Torr. The salt rejection remained high (up to 99.9%) under all operating conditions. A high water flux of 11.7 kg/m 2 ·hr could be achieved at a feed temperature of 65°C and a vacuum of 6 Torr. The effect of operating conditions on water flux is discussed in relation to diffusion coefficients of water and fundamental transport mechanism through the membrane. The activation energy for water permeation was found to vary from 23.8 to 20.1 kJ/kmol when the salt concentration in the feed was increased from 0.2 to 5.0 wt%.

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Pervaporation of Alcohols and Methyl tert-Butyl Ether through a Dense Poly(2,6-dimethyl-1,4-phenylene oxide) Membrane

Cited by 19 publications

References 63 publications

Effect of heat treatment on pervaporation separation of aqueous salt solution using hybrid PVA/MA/TEOS membrane

Effect of heat treatment on pervaporation separation of aqueous salt solution using hybrid PVA/MA/TEOS membrane

Sol–gel derived poly(vinyl alcohol)/maleic acid/silica hybrid membrane for desalination by pervaporation

Separation of aqueous salt solution by pervaporation through hybrid organic–inorganic membrane: Effect of operating conditions

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