• Journal of the Korean institute of surface engineering
• /
• v.37 no.5
• /
• pp.289-295
• /
• 2004

A dense palladium-nikel (Pd-Ni) alloy composite membrane has been fabricated on microporous nickel support mixed with submicron/micron nickel powder instead of mesoporous stainless steel support. Plasma treatment process is introduced as pre-treatment process instead of HCI activation. Pd-Ni alloy composite membrane prepared by electro plating was fairly a uniform and dense surface morphology. The membrane was characterized by permeation experiments with hydrogen and nitrogen gases at temperature 773 K and pressure 2.2 psi. The results showed that hydrogen ($H_2$) permeance was 27 ml/$\textrm{cm}^2$ㆍatmㆍmin and hydrogen/ nitrogen ($_H2$$N_2$) selectivity was 8 at 773 K.

• Journal of the Korean Chemical Society
• /
• v.38 no.2
• /
• pp.122-128
• /
• 1994

Macrocyclic ligand has been known to selectively bind with metal ions so that ability applied for the transport of metal ions across the emulsion liquid membrane in this study. The metal ions are transproted from the source phase to the receiving phase by the carrier of the organic phase. Several factors involved in the transport of metal ions acrose the emulsion membrane we reported here and these factors provided the informations for the selective seperation of some metal ion. Stability constants for cation-macrocyclic ligand and metal ion-anion receiving phase interaction are examined as parameters for the prediction of metal ion transport selectivities. $Pb^{2+}$ was transported higher rates than the other metal ions in the mixture solution. The interaction of metal ion to anion in receiving phase is important. $S_2O_3^{2-}$- in replacement of $NO_3^-$ in the receiving phase enhances the transport of $Pb^{2-}$since $Pb^{2-}-S_2O_3^{2-}$interaction is greater than $Pb^{2+}-NO_3^-$ interaction.

• Membrane Journal
• /
• v.29 no.3
• /
• pp.123-129
• /
• 2019

Environmental pollution caused by the presence of heavy metal ion from growing industrialization or from leaching is increasing area of concern. There are several area of water purifications but among them adsorption on the functionalized polymer fibers is efficient and cost-effective method. Polyacrylonitrile (PAN) is exciting polymer due to the presence of excessive functional group which can be easily transformed for metal ion adsorption. PAN can be easily electrospun to prepare nanofiber that have higher surface area leading to better metal ion removal. Composite PAN fiber is yet another type of polymer covered in this review for waste water treatment.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.44-44
• /
• 2003

Growth mechanism of carbon nanotubes(CNTs) synthesized by chemical vapor deposition is abided by two growth modes. These growth modes are classified by the position of activated catalytic metal particle in the CNTs. Growth mode can be also affected by interaction between substrate and catalytic metal and induced energy such as thermal and plasma. We studied the reaction of catalytic metal to the substrate and growth mode of CNTs. Various substrates such as Si(100), graphite plate, coming glass, sapphire and AAO membrane are used to study the relation between catalytic metal and substrate in the synthesis of CNTs. For catalytic metal, thin film was deposited on various substrate via sputtering technique with a thickness of ∼20nm and magnetic fluids with none-sized particles were dispersed on AAO membrane. After laying process on AAO membrane, it was dried at 80$^{\circ}C$ for 8 hour. Synthesizing of CNTs was carried out at 900$^{\circ}C$ in NH3/C2H2 mixture gases flow for 10minutes.

• Journal of the Korean Chemical Society
• /
• v.28 no.2
• /
• pp.86-94
• /
• 1984

The single crystal ion-selective electrode,$ {\beta}-Ag_3SI/PVC-THF $membrane electrode has showed a linear potential response to the activities of iodide ion (10-1${\sim}$10-7M). The $ {\beta}-Ag_3SI$ membrane electrode was compared with AgI/PVC-THF membrane and copper metal plate membrane electrodes. In order to measure the selectivity coefficient of the electrodes toward $Cl^-$ and $Br^-$, the separation and mixed solution method were employed. The potential-time curve was obtained by the usual immersion technique and pH effect was also examined. The orders of selectivity for $Br^-$, $Cl^-$ and stability of response time are ${\beta}-Ag_3SI/PVC-THF $membrane > AgI/PVC-THF membrane > copper metal plate membrane. These electrodes could be used as indicating electrodes in the potentiometric titration of a single halide and mixed halides with the standard solution of silver nitrate.

• Journal of Ocean Engineering and Technology
• /
• v.12 no.2 s.28
• /
• pp.57-64
• /
• 1998

This study is concerned with criterion for membrane to shell conversion in two-dimensional elastic-plastic finite element analysis using membrane/shell mixed element. It is well known that in the sheet metal forming some parts of the sheet deform under almost pure stretching (membrane) conditions, whereas other parts in contact with sharp tooling surfaces can develop significant bending strains. The membrane analysis has a short computational time however, in the membrane analysis the bending effects can not be condidered at all. On the other hand, the shell analysis allows the consideration of bending effects, but involves too much computational time. So Onatel),2), Yang et al3),4) developed the membrane/shell mixed element. Onate introduced the energy ratio parameter and Yang et al introduced the ratio of thickness to radius of curvature as the criterion. In the present study we propose a new criterion by using the angle between both side elements in the nodal point.

• Membrane Journal
• /
• v.32 no.6
• /
• pp.367-382
• /
• 2022

Numerous metal-organic frameworks (MOFs) produced by periodic combinations of organic ligands and metal ions or metal-oxo clusters have led the way for the creation of energy-efficient membrane-based separations that may serve as viable replacements for traditional thermal counterparts. Although tremendous progress has been made over the past decade in the synthesis of polycrystalline MOF membranes, only a small number of MOFs have been exploited in the relevant research. Intercrystalline defects, or nonselective diffusion routes in polycrystalline membranes, are likely the reason behind the delay. Postsynthetic modifications (PSMs) are newly emerging strategies for providing polycrystalline MOF membrane diversity by leveraging advanced membranes as a platform and improving their separation capabilities via physical and/or chemical treatments; therefore, neither designing and developing MOFs nor tailoring membrane synthesis techniques for focused MOFs is necessary. In this minireview, seven subclasses of PSM techniques that have recently been adapted to polycrystalline MOF membranes are outlined, along with obstacles and future directions.

• Membrane Journal
• /
• v.28 no.4
• /
• pp.252-259
• /
• 2018

An acidic, real metal-plating wastewater was treated by a fluidized bed membrane reactor introduced with granular activated carbon (GAC) as fluidized media. With GAC fluidization, there was no increase in suction pressure with time at each flux set-point applied. At neutral solution pH, much less fouling rate was observed than acidic pH under GAC fluidization. Higher solution pH resulted in the increase in particle size in metal-finishing wastewater, thus producing a less dense cake structure on membrane. More than 95% of chemical oxygen demand was observed from the fluidized bed membrane reactor under GAC fluidization. Total suspended solid concentration in membrane permeate was near zero. At the raw wastewater pH, no removal of copper and chromium by the fluidized bed membrane reactor was observed. As the pH was increased to 7.0, removal efficiency of copper and chromium was increased considerably to 99 and 94%, respectively. Regardless of solution pH tested, more than 95% of cyanide was removed possibly due to the strong adsorption of organic-cyanide complex on GAC in fluidized bed membrane reactor.

• Transactions of Materials Processing
• /
• v.8 no.4
• /
• pp.347-355
• /
• 1999

The paper is concerned with an improved scheme for application of the blank holding force in order to take account of the thickness distribution in the sheet material of the flange region. The scheme incorporates with a modified membrane finite element method for planar anisotropic materials. The new scheme proposed two coefficients α and βto calculate the compressive stress in the sheet metal due to the blank holding force, which should be determined properly for accurate analysis. The effect of αand βon the blank holding force distribution and the deformed shape is investigated with simulation of rectangular cup deep drawing processes by changing parameter values.

• Membrane and Water Treatment
• /
• v.9 no.1
• /
• pp.63-68
• /
• 2018

Molecular dynamics simulations were used to study the removal of Cd(II) as a heavy metal from wastewater using armchair carbon nanotube, boron nitride nanotube and silicon carbide nanotubes under applied electric field. The system contains an aqueous solution of $CdCl_2$ as a heavy metal and a (7,7) nanotube as a nanostructured membrane, embedded in a silicon nitride membrane. An external electric field was applied to the considered system for the removal of $Cd^{2+}$ through nanotubes. The simulation results show that in the same conditions, considered armchair nanotubes were capable to remove $Cd^{2+}$ from wastewater with different ratios. Our results reveal that the removal of heavy metals ions through armchair carbon, boron nitride and silicon carbide nanotubes was attributed to the applied electric field. The selective removal phenomenon is explained with the calculation of potential of mean force. Therefore, the investigated systems can be recommended as a model for the water treatment.