Modification of Performances of Various Membranes Using MWNTs as a Modifier

Abstract

Summary: The effect of multi-walled carbon nanotubes (MWNTs) incorporated for the modification of membrane performances was studied. Two different types of membranes were prepared by using MWNTs: one was polysulfone (PSf) ultrafiltration (UF) membrane and the other was polyvinyl alcohol (PVA) pervaporation membrane. The PSf UF membranes with different contents of MWNTs were prepared by the conventional phase inversion process, and used for water-treatment. On the other hand, the PVA membranes with different amount of MWNTs were prepared by the casting and drying method, and used for the pervaporation separation of water out of ethanol solution containing 10% of water. The two different types of membranes were then characterized with several analytical methods to figure out how the MWNTs were distributed through the membranes and affect on the properties of them: For the PSf membranes, the MWNTs mainly located on the surface of the membranes made them more hydrophilic and improved the selective permeation performances of the membranes. In the case of the PVA membranes, the MWNTs were distributed rather homogeneously through out the membranes, and affected on the micro-morphology of the membranes, causing them to have different pervaporation performances.

Multilayer mixed matrix membranes containing modified-MWCNTs for dehydration of alcohol by pervaporation process

“…Thus the ratio of water to ethanol partial fluxes and the separation factor enhance. Similar results have been reported in the literature [17,27,28]. For example, Shirazi et al [28] prepared PVA-CNT nanocomposite membranes for dehydration of isopropanol aqueous solutions and observed that incorporating CNTs in the PVA matrix significantly increases water separation factor due to rigidification of the polymer chains.…”

“…Furthermore, several inorganic compounds have been used as filler in the synthesis of the mixed matrix membranes for solvent dehydration by the pervaporation process. For example, zeolite [5][6][7]17,18,23], titanium oxide (TiO 2 ) [24,25], iron [22], sodium montmorillonite clay [26], carbon nanotubes (CNTs) [27][28][29] and silica [30]. There are some drawbacks in the preparation of mixed matrix membranes such as poor distribution of the filler in the polymer matrix and weak contact of inorganic filler particles in the polymer matrix.…”

Influence of Functionalized Multiwall Carbon Nano-Tube on the Structure and Performance of Cellulose Di-Acetate Based Forward Osmotic Membrane for Desalination Process

“…For example, the initial contact angle of M-4 top surface was about 75°, which drop 12°C in the first 10s and then slowly decreases 57°C in 120s, indicating improved hydrophilicity from the pure CDA membrane. Similar phenomenon had been reported by Choi et al [32]. This result can be explained by the fact that during the phase inversion process, hydrophilic MWCNTs migrated spontaneously to the membrane/water interface to reduce the interface energy [33].…”

Novel ultrafiltration membranes prepared from a multi-walled carbon nanotubes/polymer composite

“…which was derived from the Hagen-Poiseuille's equation [18]. Here, r, , Â, P, and Q are the pore radius, the interfacial tension of water/i-pentanol, the contact angle at the interface of water phase and polymer, the applied pressure, and the permeate flow rate, respectively.…”

“…Nowadays, there are more reports on the fluid transport through porous CNTs/polymer membrane. Choi et al prepared acidified-MWNTs/polysulfone (PSf) membranes through an immersed phase inversion process using N-methyl-2-pyrrolidinone (NMP) as a solvent and water as a coagulant [17,18]. Qiu et al prepared MWNTs/PSf membranes containing MWNTs functionalized by isocyanate and isophthaloyl chloride groups via the reaction between carboxylated carbon nanotubes and 5-isocyanato-isophthaloyl chloride [19].…”