Transport of Indium, Gallium and Thallium Metal Ions Through Chromatographic Fiber Supported Solid Membrane in Acetylacetone Containing Mixed Solvents

The transport of metal ions of indium, gallium and thallium from source solution to receiving phase through the chromatographic fiber supported solid membrane in the acetylacetone （HAA） containing mixed solvent system has been explored. The fibers supported solid membranes were prepared with chemical synthesis from cellulose fibers and citric acid with the carboxylic acid ion exchange groups introduced. The experimental variables, such as concentration of metal ions （10^-2 to 10^-4 mol.L^-1） in the source solution, mixed solvent composition [for exampl, e, acetylacetone, （2,4-pentanedione）, （HAA） 20% （by volume）, 1,4-dioxane 10% to 60% and HC1 0.25 to 2 mol.L^-1] in the receiving phase and stirring speed （50-130 r.min ） of the bulk source and receiving phase, were explored. The efficiency of mixed solvents for the transport of metal ions from the source to receiving phase through the fiber supported solid membrane was evaluated. The combined ion exchange solvent extraction （CIESE） was observed effective for the selective transport of thallium, indium and gallium metal ions through fiber supported solid membrane in mixed solvents. The oxonium salt formation in the receiving phase enhances thallium, indium and gallium metal ion transport through solid membrane phase. The selective transport of thallium metal ions from source phase was observed from indium and gallium metal ions in the presence of hydrochloric acid in organic solvents in receiving phase. The separation of thallium metal ions from the binary mixtures of Be（II）, Ti（IV）, AI（III） Ca（II）, Mg（II）, K （I）, La（III） and Y（III） was carried out in the mixed solvent system using cellulose fiber supported solid membrane.

Solid oxide membrane-assisted electrolytic reduction of Cr_(2)O_(3) in molten CaCl_(2)

Solid oxide membrane-assisted electrolytic reduction of solid Cr_(2)O_(3) to Cr in molten CaCl_(2) was performed using a sintered porous Cr_(2)O_(3) cathode paired with an yttria-stabilized zirconia(YSZ)tube anode containing carbon-saturated liquid copper alloy.Analyses of the reduction mechanism,ion migration behavior,and effects of cathode pellet porosity and particle size on the electrolysis products and reduction rate revealed that the cathode microstructure and electrolytic conditions were key factors influencing the electrolysis process.Optimal results were obtained when the cathode was characterized by high porosity and a small particle size because this combination of features contributed to ion migration.Good electrochemical activation was observed when cathode pellets prepared by 4 MPa molding followed by 2 h of sintering at 1150℃ were applied.The electrode reduction process(Cr^(3+)→Cr^(2+)→Cr)was promoted by high electrode voltages,and Cr metal was efficiently formed.The proposed method appears to be well suited for electrolytic Cr production because it does not require expensive pre-electrolysis techniques or generate harmful by-products.

Methane Conversion to C_2 Hydrocarbons in Solid State Oxide Electrolyte Membrane Reactor

Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examined in a fixed-bed reactor. The former group presented higher activity in the OCM, but the main product was carbon dioxide. While the later group showed lower activity but much higher selectivity to C2 hydrocarbons compared with the former. Electrochemical measurements were conducted in a solid oxide membrane reactor with La0.8 Na0.2CoO3 as catalyst. The results showed that methane was oxidized to carbon dioxide and ethane by two parallel reactions. Ethane was oxidized to ethene and carbon dioxide. A fraction of ethene was oxidized deeply to carbon dioxide. The total selectivity to C2 hydrocarbons exceeded 70%. Based on the experimental results, a kinetic model was suggested to describe the reaction results.

Effect of Hydrogen Reduction of Silver Ions on the Performance and Structure of New Solid Polymer Electrolyte PEI/Pebax2533/AgBF4 Composite Membranes

In this paper, the effect of hydrogen reduction of silver ions on the performance and structure of new solid polymer electrolyte polyetherimide （PEI）/Pebax2533 （Polynylonl2/tetramethylene oxide block copolymer, PA12-PTMO）/AgBF4 composite membranes is investigated. For PEI/Pebax2533/AgBF4 composite membranesprepared with dillerent AgBF4 concentration, the permeances of propylene and ethylene increase with the increase of AgBF4 concentration due to the carrier-facilitated transport, resulting in a high selectivity. But for propyl- ene/propane mixture, the mixed-gas selectivity is lower than its ideal selectivity. The hydrogen reduction strongly influences the membrane performance, which causes the decrease of propylene permeance and the increase of pro-pane permeance. With the increase of hydrogen reduction time, the membranes show a clearly color change from white to brown, yielding a great selectivity loss. The data of X-ray diffraction and FT-IR prove that silver ions are reduced to Ago after hydrogen reduction, and aggregated on the surface of PEI/Pebax2533/AgBF4 composite mem- branes.

Study on the Long Term Sensing Properties of pCO_2 Sensitive Electrode

In this paper,the pCO_2 sensitive electrode was studied for continuous measurement.The solid electrolyte membrane and gas-permeable membrane were coated on the surface of the pH sensitive electrode which was fabricated based on the SnO_2/ITO glass substrate.According to the experimental results,the pCO_2 sensitive electrode shows the sensitivity of about 35 mV/decade in detection range between 0.1 mmol/L and 50 mmol/L.Moreover,the investigated sensing structure exhibits the convenient and pragmatic properties of the pCO_2 measurement.In summary,the advantages of the pCO_2 sensitive electrode are low-cost and disposable based on the separative structure.