Preparation and properties of hydrophobic poly(vinylidene fluoride)–SiO₂ mixed matrix membranes for dissolved oxygen removal from water

Abstract

The application of the membrane method for removing dissolved oxygen (DO) from water on the laboratory scale was studied. Flat mixed matrix membranes were composed of poly(vinylidene fluoride) (PVDF) and hydrophobic nanosilica particles, which were used to improve the DO removal process. The SiO 2 particles were modified by a silane coupling agent and examined by Fourier transform infrared spectroscopy. It was shown that the surface of the SiO 2 particles was bonded to hydrophobic longchain alkane groups through chemical bonding. The effects of adding SiO 2 particles on the membrane properties and morphology were examined. The results show that the porosity and pore size of the membrane were affected by the introduction of SiO 2 particles, and the cross-sectional morphology of the PVDF composite membranes changed from fingerlike macrovoids to a spongelike structure. The membrane performance of DO removal was evaluated through the membrane unit by a vacuum degassing process. It was found that the SiO 2 /PVDF hybrid membranes effectively improved the oxygen removal efficiency compared with the original PVDF membranes. The maximum permeation flux was obtained when the loading amount was 2.5 wt %. The effect of the downstream vacuum level was also investigated. The experimental results show that the SiO 2 /PVDF hybrid membranes had superior performances and could be an alternative membrane for removing DO from water.

Preparation and structures of PEBA gas separation membrane modified by fumed silica for oil vapor separation

“…Hydrophobic separation membranes are widely used in gas separation owing to their special hydrophobicity and selective separation characteristics. How to endow a separation membrane with excellent hydrophobicity had always been one of the main directions of gas separation membrane research 21 .…”

Hydrophilic–hydrophobic polymer based blend membrane for separation of water–isopropanol mixtures by pervaporation

“…However, selectivity in dehydration of water from alcohol such as IPA is less. The permeation of alcohol can be reduced and water can be improved by modifying the PVA matrix [13][14][15][16][17][18][19]. The excessive swelling of PVA can be reduced by blending with hydrophobic PSA and PSM polymers, which can be expected to decrease the molecular transfer of alcohol molecules.…”

“…To improve its overall membrane performance in pervaporation separation, PVA needs to modify to achieve good mechanical stability and attain better selectivity in the dehydration of organic solvents. PVA has been subjected to modification through cross-linking [15], blending with other hydrophilic polymers [16], grafting [17], mixed matrix [18], zeolite filling [19], blending with hydrophobic polymer [20,21], etc. Apart from these modifications, nano-hybrid [22], nanocomposite [23], hydrophobic composite membrane [24], sulphonated PVA membrane [25], multi-walled carbon nanotube incorporated PVA membrane [26], inorganic/organic hybrid nanocomposite membranes [27], different types of cross-linked PVA membrane [28], PVA ceramic membrane [29] and iron oxide nanocomposite [30] based on PVA were also reported in the literature for PV applications.…”

Визначення Ефективності Знекиснення Води Різної Мінералізації

“…Physical methods for degassing include the thermal degassing, vacuum degassing, nitrogen purging, desorption, and membrane degassing [9][10][11][12][13][14][15][16].…”