Controlling the transport of cations through permselective mesoporous alumina layers by manipulation of electric field and ionic strength

Electrosorption capacitance of nanostructured carbon-based materials

“…Since the nanostructured carbon materials consist of mesopores and micropores, EDL overlapping becomes a key factor in ion transport and EDL capacitance can thus be reduced by the overlapping effect [5,14]. More specifically, the occurrence of EDL overlapping can be used to explain the mechanism by which membranes containing channels of molecular dimensions can show selective ion transport, mimicking biological transport processes [16,17]. A model describing the formation of the EDL inside pores was developed by taking into consideration a double-layer overlapping correction [18].…”

Recovery of Homogeneous Polyoxometallate Catalysts from Aqueous and Organic Media by a Mesoporous Ceramic Membrane without Loss of Catalytic Activity

“…The real pore radius, r p , is related to the Kelvin radius, r K , shown in Figure 1, by r p = r K + t, where t~0.3 nm. [11] Hence the average pore radii of g-600 and g-900 are 2.3 and 4.0 nm, respectively. Table 1 lists typical retention values of Na 12 POM and Q 12 POM catalysts by g-600 and g-900 membranes.…”

“…The pore-size distribution of the g-alumina membranes was determined by permporometry using a home-made setup. [11] Epoxidation and POM catalyst recycling: Q 12 POM (5 mL of a 6.4 mm solution in toluene; 32 mmol), toluene (10 mL), dodecane (0.5 mL; internal standard) and cyclooctene (2.6 mL, 20 mmol) were mixed and heated to 60 8C. H 2 O 2 (50 % solution in H 2 O; 1.5 mL, 27 mmol) was then added in five portions over a period of 2 h (300 mL per half hour) and the biphasic mixture was stirred at 60 8C.…”

Surfactant‐Modulated Switching of Molecular Transport in Nanometer‐Sized Pores of Membrane Gates

“…[8,9] They may enable new ways of molecular separation, dosing, and analysis. [1][2][3][4][5][6][7] The channels or pores of the gate typically have diameters of % 20 nm or less in order to function properly. The operating principle is based on the presence of 1) a driving force for species transport, usually a concentration or electrical potential gradient over the gate, and 2) an externally controllable switch with which the gate can be opened or closed, or the selectivity of the gate modified.…”

“…[13][14][15] However, the control of ionic strength and surface charge to manipulate the permeability of a membrane is limited to dilute conditions under which double-layer overlap inside the channel/pore occurs, that is, at relatively low ionic strengths, when charge exclusion is sufficient to reject ions. [5][6][7] A much more universal method of tuning the permeability of molecular gates would be the controlled steric blocking of permeating species. By physically blocking or unblocking the channels of a gate, an open/closed system can be created.…”