Due to its high chemical stability,good thermal resis ta nce, ideal conductivity and ion-selective permeability, Nafion membrane has bee n used in many electrochemical systems.The significant progress has been made in...Due to its high chemical stability,good thermal resis ta nce, ideal conductivity and ion-selective permeability, Nafion membrane has bee n used in many electrochemical systems.The significant progress has been made in the applied research of Nafion membranes in fuel cell, membrane separation and organic electro-synthesis.For organic electro-synthesis,the studies on permeat ion of organic compounds through the membrane were seldom reported in literature .3-methylpyridine is the main raw material for electrochemical synthesis of nia cin.In this work, the permeating fluxes of 3-methylpyridine were measured in th e H 2SO 4 aqueous solution at different concentrations and temperatures.The re sults showed that the permeating flux was directly proportional to the molar con centration of 3-methylpyridine at a given temperature.The relationship between the natural logarithm of proportional coefficient and the reciprocal of temperat ure was linear.The Arrhenius equation for the relationship between permeating fl ux and temperature was obtained.The apparent activation energy and apparent pre -exponential factor were estimated as 63.3 kJ·mol -1 and 2.69×108 m ·h -1.展开更多
Nafion/TiO2 composite membranes were prepared by in-situ chemical reaction method using Ti(OC4H9)4 and Nafion 117 as raw materials. The membranes were characterized by UV, FTIR-ATR and XRD, respectively. Methanol perm...Nafion/TiO2 composite membranes were prepared by in-situ chemical reaction method using Ti(OC4H9)4 and Nafion 117 as raw materials. The membranes were characterized by UV, FTIR-ATR and XRD, respectively. Methanol permeability and water uptake were investigated as a function of TiO2 contents. The conductivity of the membranes was measured under water vapor pressure (2.644 7 kPa) or in dry atmospheres. The XRD results showed that the titanium dioxide in Nafion membranes were crystallized in anatase phase with an average crys- taline diameter of 3.0 nm. The water uptake of the composite membranes was larger than that of the pure Nafion○ membrane when the TiO2 loading was within 14wt%. The methanol permeability of the membrane decreased as the TiO2 loading increased. The addition of 3wt% TiO2 to Nafion○ membranes improved the conductivity in dry measurement conditions. The proton conductivity of the composite membrane increased greatly after the hy- drothermal treatment at 160 ℃ for 2 hours.展开更多
文摘Due to its high chemical stability,good thermal resis ta nce, ideal conductivity and ion-selective permeability, Nafion membrane has bee n used in many electrochemical systems.The significant progress has been made in the applied research of Nafion membranes in fuel cell, membrane separation and organic electro-synthesis.For organic electro-synthesis,the studies on permeat ion of organic compounds through the membrane were seldom reported in literature .3-methylpyridine is the main raw material for electrochemical synthesis of nia cin.In this work, the permeating fluxes of 3-methylpyridine were measured in th e H 2SO 4 aqueous solution at different concentrations and temperatures.The re sults showed that the permeating flux was directly proportional to the molar con centration of 3-methylpyridine at a given temperature.The relationship between the natural logarithm of proportional coefficient and the reciprocal of temperat ure was linear.The Arrhenius equation for the relationship between permeating fl ux and temperature was obtained.The apparent activation energy and apparent pre -exponential factor were estimated as 63.3 kJ·mol -1 and 2.69×108 m ·h -1.
文摘Nafion/TiO2 composite membranes were prepared by in-situ chemical reaction method using Ti(OC4H9)4 and Nafion 117 as raw materials. The membranes were characterized by UV, FTIR-ATR and XRD, respectively. Methanol permeability and water uptake were investigated as a function of TiO2 contents. The conductivity of the membranes was measured under water vapor pressure (2.644 7 kPa) or in dry atmospheres. The XRD results showed that the titanium dioxide in Nafion membranes were crystallized in anatase phase with an average crys- taline diameter of 3.0 nm. The water uptake of the composite membranes was larger than that of the pure Nafion○ membrane when the TiO2 loading was within 14wt%. The methanol permeability of the membrane decreased as the TiO2 loading increased. The addition of 3wt% TiO2 to Nafion○ membranes improved the conductivity in dry measurement conditions. The proton conductivity of the composite membrane increased greatly after the hy- drothermal treatment at 160 ℃ for 2 hours.
