Organic nanocomposite membranes

The preferential affinity to EtOH depends on the balance between the hydro-philicity and the hydrophobicity of the membrane s material (Huang 1991). Qiu and Peinemann (2006) developed novel organic nanocomposite membrane for PV. The basic polymers were PDMS and poly(l-trimethylsilyl-l-propyne) (PTMSP). By implanting the hydrophobic organic molecules in PTMSP and PDMS, permselectivity to EtOH was enhanced. For example, PDMS with 20 wt% a-cyclodextrins provides a separation factor of 12 for EtOH (5 wt%)-water (95 wt%). Similarly, PTMSP with only 8 wt% a-cyclodextrins improved the enrichment of the low concentration of EtOH from 5 to 48 wt% and maintained the flux at 9 kg pm/m h. They claimed that the increased performance in EtOH-water separation with this organic nanocomposite membrane may lead to the practical industrial application by means of the PV process to produce bioethanol. 

I. Honma, Y. Takeda, J.M. Bab, Protonic conducting properties of sol-gel derived organic/inorganic nanocomposite membranes doped with acidic... 

Recently, in our group, we evaluated the potentiality of a poly(iniide) (PI)/ organically-modified montmorillonite (O-MMT) nanocomposite membrane for the use in alkaline fuel cells [73]. Both X-ray diffraction and scanning electron microscopy revealed a good dispersion of O-MMT into the PI matrix and preservation of the O-MMT layered structure. When compared to the pure PI, the addition of O-MMT improved thermal stability and markedly increased the capability of absorbing electrolyte and ionic conductivity of the composite. Based on these results, the PI/ O-MMT nanocomposite is a promising candidate for alkaline fuel cell appUcations. 

Tripathi, B.P., Kumar, M., Saxena, A. and Shahi, V.K. 2010. Bifunctionalized organic-inorganic charged nanocomposite membrane for pervaporation dehydration of ethanol. J. Colloid Interface Sei. 346 54-60. 

A new polymer-inorganic nanocomposite SPEEK membrane filled with Cloisite 15A clay by introducing 2,4,6-triaminopyrimidine (TAP) as the compatibilizer for DMFC applications has been successfully prepared. The organoclay Cloisite is a material prepared from MMT and the cation ditallow. Tallow is a mixture of octa-decyl, hexadecyl, and tetradecyl, wherein octadecyl is the major component (>60%). Cloisite is a very promising additive in nanocomposite membranes, since it is already being organically modified from the natural MMT, which is expected to enhance the compatibility with organic polymers (Cervantes-Uc et al. 2007). 

Reprinted from S. Sonihas, P. Gorgojo, C. T6Uez, J. Coronas, A.G. Livingston, High flux thin flhn nanocomposite membranes based on metal-oiganic frameworks for organic solvent nanoflltration, Journal of the American Chemical Society 135 (2013) 15201-15208. 

M. Peyravi, M. Jahanshahi, A. Rahimpour, A. Javadi, S. Hajavi, Novel thin film nanocomposite membranes incorporated with functionalized Ti02 nanoparticles for organic solvent nanofiltration, Chemical Engineering Journal 241 (2014) 155-166. 

In a distinct vein, BC/chitosan membranes have been tested for pervaporative separation of binary aqueous-organic mixtures (ethanol/water) [111]. The substantially high pervaporative separation index (350 kg. x.m. h 0 and low activation energy (10 kj.mol ) are indicative of the high potential of BC/chitosan membranes in the pervaporative separation of ethanol/water azeotrope. Targeting to mimic the intrinsic antimicrobial properties of chitosan on BC nanofibrils, nanostructured BC nanocomposite membranes were obtained by surface functionalization with aminoalkyl groups (Figure 2.14) [114]. These bioactive nanostructured membranes also presented improved mechanical and thermal properties and may be useful for biomedical applications. 

Heller J., Heller A. Loss of activity or gain in stability of oxidases upon their immobilization in hydrated sihca Significance of the electrostatic interactions of surface arginine residues at the entrances of the reaction channels. J Am Chem. Soc. 1998 120(19) 4586-4590 Honma L., Takeda Y., Bae J.M. Protonic conducting properties of sol-gel derived organic/inorganic nanocomposite membranes doped with acidic functional molecules. Solid State Ionics 1999 120(1-1) 255-264... 

Ghaemi, N., S. S. Madaeni, A. Alizadeh, H. Rajabi, and P. Daraei. 2011. Preparation, characterization and performance of polyethersutfone/organically modified montmorillonite nanocomposite membranes in removal of pesticides. Journal of Membrane Science 382 (1-2) (October) 135-147. doi 10.1016/jjnemsci.2011.08.004. http // linkinghub.elsevier.com/retrieve/pii/S0376738811005813. 

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