Sharif Digital Repository

In this study, modification of polyvinyl chloride (PVC) ultrafiltration membranes with zinc oxide (ZnO) nanoparticle addition was taken into consideration. The ZnO at five different weights was added to the polymeric solution, and the membranes were fabricated by the phase inversion method using water as a nonsolvent and PEG 6 kDa as a pore former additive. The results showed that the pure water flux of the modified membranes increased up to 3 wt% ZnO addition, which was the optimized amount of the nanoparticle addition in this study. Also, at 3 wt% ZnO addition, flux recovery ratio reached from 69% to above 90%, indicated that the nanocomposite membranes were less susceptible to be fouled.... 

Interesting properties of ionic liquids lead to their application as sub-component of membrane structures. Supported ionic liquid membranes (SILMs) are porous membranes whose pores are saturated with ionic liquids. Two ionic liquids, pr[mim]2[Tf2N]2 [1,3-di(3-methyl-imidazolium) propane bis(trifluoromethylsulfonyl) imide] and, h[mim]2 [Tf2N]2 [(1,6-di(3-methylimidazolium)hexane bis(trifluoromethylsulfonyl)imide)], were synthesized in our laboratory and stabilized on an alumina porous support. Permeability and permselectivity of carbon dioxide and methane using membranes containing these ionic liquids were then measured. The experiments were performed in the pressure range of 10-50kPa and... 

Monitoring conformational changes in ion channels is essential to understand their gating mechanism. Here, we explore the structural dynamics of four outer membrane proteins with different structures and functions in the slowest nonzero modes of vibration. Normal mode analysis was performed on the modified elastic network model of channel in the membrane. According to our results, when membrane proteins were analyzed in the dominant mode, the composed pores, TolC and α-hemolysin showed large motions at the intramembrane β-barrel region while, in other porins, OmpA and OmpF, largest motions observed in the region of external flexible loops. A criterion based on equipartition theorem was used... 

A theoretical model concerning simultaneous diffusion and reaction was developed to describe the steady state behavior of a cationic glucose-sensitive membrane with consideration of oxygen limitation and swelling-dependent diffusivities of involved species inside the membrane. Donnan equilibrium was used to find concentrations of buffer ions inside the membrane. The profiles of species concentrations, pH, polymer volume fraction and solute diffusivity inside the membrane were predicted by the model in response to step changes of glucose concentration in the external solution. The influence of various factors on the responsiveness of the membrane was analyzed using the model. The results... 

The purpose of this study is to investigate separation performance of poly(ether-b-amide6) (Pebax1657)/glycerol triacetate (GTA) gel membranes for CO2 removal from H2, N2 and CH4. GTA as a low molecular weight and highly CO2-phill compound was added to membrane structure at various weight fractions, 20%, 40%, 60% and 80% of Pebax, to fabricate a new high solubility selective membrane with improved performance. Permeation of pure gases was studied at different temperatures from 25 to 65°C and pressures from 4 to 24bar and ideal selectivities were calculated. Results indicated enhancement in permeation for all tested gases. For example, at a pressure of 4bar and a temperature of 25°C, membrane...