Transport mechanisms of water and organic solvents through microporous silica in the pervaporation of binary liquids

Separation Performance of Sodium Alginate/Poly Vinyl Pyrrolidone Membranes for Aqueous/Dimethylformamide Mixtures by Vapor Permeation and Vapor Permeation with Temperature Difference Methods

“…As a result, the permeation rate increases whereas the separation factor decreases with increasing temperature. Similar results were reported in the literature [20][21][22][23]. Sommer and Melin [22] studied influence of operation parameters on the separation of mixtures by pervaporation and vapor permeation with silica membranes.…”

Structure–property tuning in hydrothermally stable sol–gel-processed hybrid organosilica molecular sieving membranes

“…TEOS-derived silica is very permeable to small species with a kinetic diameter \0.3 nm like H 2 , He and H 2 O and impermeable to large gases like SF 6 (0.55 nm) and large organic molecules such as ethanol and n-butanol ([0.4 nm) [77]. The first reports demonstrating that hybrid organosilica membranes also have molecular sieving properties were published in 2008 [7,19].…”

“…The high water flux is likely at least partly due to the hydrophilic nature of the membrane. However, BTESM also showed a remarkable ability to separate water from lower alcohols, including the notoriously difficult molecular separation methanol-water [25,77]. Using a 5:95 wt/wt water-methanol mixture at the feed side, a permeate stream containing 55:45 wt/wt watermethanol was accomplished (a H 2 O=MeOH = 23), see Fig.…”

“…The only exception is CO 2 which tends to adsorb on the pore surface. The activation energy of permeability is the activation energy of diffusion minus the heat of sorption of the molecule on the inner pore wall [77], which is why its value can be either positive or negative. For CO 2 , the activation energy is usually negative, since it adsorbs relatively strongly on micropore walls in silica and methylated silica, with corresponding heats of sorption that are larger than its activation energy of diffusion.…”

Catalytic Properties of Platinum Nanoparticles Obtained in a Single Step Simultaneous Reduction of Pt(IV) Ions and Graphene Oxide

“…It is known that the diameter of the glucose molecule is equal to 1.5 nm [33]. Our experiments showed that PtNPs-rGO did not catalyze methanol oxidation whose molecule size is smaller than that of glucose (kinetic diameter of methanol is equal to 0.38-0.41 nm) [34]. This fact in turn clearly suggests that not only the size but also surface characteristics of PtNPs particles, such as surface chemical properties, have a significant influence on the catalytic properties.…”