Pervaporation performance of novel chitosan‐POSS hybrid membranes: Effects of POSS and operating conditions

Abstract

Four types of polyhedral oligosilsesquioxane (POSS)octaanion, octaammonium, octanitrophenyl, and octaaminophenyl-were incorporated into chitosan (CS) to fabricate inorganic-organic hybrid membranes. The hybrid membranes were employed for the pervaporation dehydration of ethanol aqueous solutions. The performance of the hybrid membranes was found to be influenced by the type and loading amount of POSS. In comparison with the neat CS membranes which showed a separation factor of 65.2 for 10 wt % water in the feed at 303 K, the hybrid membranes containing 5 wt % of octaanion and octaaminophenyl POSS showed high separation factors of 305.6 and 373.3, respectively. The effects of the operating condi-tions such as the feed composition and temperature on the pervaporation performance of the membranes were investigated. Activation energies for permeation in the membranes were estimated from Arrhenius relationship. The activation energies for ethanol permeation in the hybrid membranes were much higher than that in the CS membrane, which may account for the large enhancements in the selectivity of the hybrid membranes.

Mixed matrix membranes with hybrid star-shaped macromolecules for mono- and dihydric alcohols pervaporation

“…Tailoring of external surface by nanoparticles with various chemical modifications [17][18][19][20] and designing molecular-level mixed matrix membranes using cyclodextrin [21] such as polyhedral oligomeric silsesquioxane (POSS) has been proposed [22][23][24]. To obtain the pervaporation membranes with high selectivity and permeability, polymer blends have also been used as membrane material [25][26][27].…”

Characterizing carbon molecular sieve and polymeric nanocomposite membrane materials

“…When P/Po exceeded 0.4, however, they were significantly increased due to the plasticization effect. These results are in general agreement with our experimental observations, although our membrane is a composite one with lower degree o f swelling and higher selectivity [65]. [139], since that the time lag o f a binary system is a complicated issue.…”

“…This slow permeation process is attributed to the fact that the polymeric membrane is swelling constantly before the final quasi-steady state is reached. The swelling degree o f the composite membrane can be up to -180% in water solution[65]. Because the actual membrane thickness at steady state is a function o f feed humidity, the permeation flux rather than permeability is used for comparison purposes in this study.The hump inFigure 5-9 is due to water vapor at the downstream vessel being over-saturated to -1 .6 torr before condensation took place and stabilized at a pressure o f 1.3 torr, the saturated vapor pressure o f ice at the cold trap temperature[138].…”

Grafting of N‐moieties onto octa‐methyl polyhedral oligomeric silsesquioxane microstructures by sequential continuous wave and pulsed plasma

“…The incorporation of octaaminophenyl POSS (OAPS) and diepoxides or dianhydrides produce highly cross‐linked structures with enhanced thermal stability, tensile, and compressive strength used for diverse applications . In addition, the interactions between such functionalized POSS nano‐cages and polymer materials were also shown to generate interfaces allowing for improved permeability of gases, such as oxygen or solvent vapors during pervaporation operation or seawater desalination . However, in order to develop proper anchor points in POSS, the surface of POSS must contains specific reactive points …”