• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.262-262
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• 2012

Modifications of graphenes have been studied for catalytic applications due to their advantages such as high surface area, conductivity and thermal stability. In this research, individual graphene oxide (GO) sheets were exfoliated from graphite using Hummers and Offeman method. Pd nano-particles were deposited on the GO surface using Pd2+ ion exchange where hydroxyl groups on the GO act as nucleation sites of Pd nanoparticles and their dispersions. The thermal treatments of the Pd-GO in H2 flow produced Pd-Graphene nanocomposites. Their catalytic performances in Sonogashira reaction were investigated. Morphological and chemical structures of the GO, Pd-GO, and Pd-Graphene were investigated using FT-IR, XRD, TEM, STEM, and XPS. The catalytic performances have been investigated using microwave reactor.

• Korean Journal of Metals and Materials
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• 제47권6호
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• pp.349-355
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• 2009

In the solvent extraction of Ru(IV) with Alamine336, it was found that Ru took part in the reaction as $RuCl_{6}_^{2-}$ in the HCl concentration range of 1 to 5 M. Interaction parameter between hydrogen ion and $RuCl_{6}_^{2-}$ was estimated by applying Bromley equation to the extraction data. From the mixed solutions of Pd(II) and Ru(IV), the distribution coefficients of Pd were found to be higher than those of Ru in the experimental ranges. Separation factor between Pd and Ru rapidly increased with the decrease of Alamine336 concentration. About 60% of the Ru from the mixed solutions was extracted by TBP at 8.3 M HCl, while Pd was not extracted in the HCl concentration range of 1.6 to 8.3 M.

• Applied Chemistry for Engineering
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• 제9권2호
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• pp.243-248
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• 1998

This study investigated the separation and the property of palladium precipitate formed by ascorbic acid in a simulated radioactive liquid waste, which was composed of 10 elements((Pd, Ru, Rh, Nd, Cs, Sr, Fe, Ni, Zr, Mo). Pd was separated selectively by using reduction characteristics of metal ions contained in the simulated waste with ascorbic acid. When the nitric acid concentration was 0.5 M, the Pd over 99.5% was precipitated by adding 0.04 M ascorbic acid. Nitric acid concentration is important at the reduction reaction of Pd ion. The precipitation yield of Pd was decreased as the concentration of nitric acid was increased. The Pd precipitate was re-dissolved in reaching at an equilibrium when the concentration of nitric acid was high and ascorbic acid was added with a small amount. The Pd precipitate formed by ascorbic acid was Pd metal and was aggregated by particles less than $1.0{\mu}m$.

• Journal of the Korean institute of surface engineering
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• 제55권6호
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• pp.460-468
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• 2022

Due to its high electrical conductivity, low contact resistance, good weldability and high corrosion resi-stance, gold is widely used in electronic components such as connectors and printed circuit boards (PCB). Gold ion salts currently used in gold plating are largely cyan-based salts and non-cyanic salts. The cya-nide bath can be used for both high and low hardness, but the non-cyanide bath can be used for low hardness plating. Potassium gold cyanide (KAu(CN)₂) as a cyanide type and sodium gold sulfite (Na₃[Au(SO)₃]₂) salt as a non-cyanide type are most widely used. Although the cyan bath has excellent performance in plating, potassium gold cyanide (KAu(CN)₂) used in the cyan bath is classified as a poison and a toxic substance and has strong toxicity, which tends to damage the positive photoresist film and make it difficult to form a straight side-wall. There is a need to supplement this. Therefore, it is intended to supplement this with an eco-friendly process using sodium sulfite sodium salt that does not contain cyan. Therefore, the main goal is to form a gold plating layer with a controllable hardness using a non-cyanide gold plating solution. In this study, the composition of a non-cyanide gold plating solution that maintains hardness even after annealing is generated through gold-palladium alloying by adding thallium, a crystal regulator among electrolysis factors affecting the structure and hardness, and changes in plating layer structure and crystallinity before and after annealing the correlation with the hardness.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3641-3649
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• 2022

A simple solvothermal reaction was used to prepare a 3-aminopropyl-functionalized silica-gel-based adsorbent for adsorbing Pd(II) from the nitric acid solution. Scanning electron microscopy, fourier transform infrared spectroscopy, and thermogravimetry analysis were performed on the as-synthesized adsorbent to demonstrate the successful introduction of Schiff base groups. Batch experiments were used to investigate the effects of contact time, nitric acid concentration, solution temperature, and adsorption capacity. It is worth noting that the prepared adsorbent exhibited a higher affinity toward Pd(II) with the uptake approximately 100% even in a 2 M HNO₃ solution. At an equilibrium time of 5 h, the maximum adsorption capacity of Pd(II) was estimated to be 0.452 mmol/g. The adsorbed Pd(II) could be completely eluted by dissolving 0.2 M thiourea solution in 0.1 M HNO₃. Using a combination of particle-induced X-ray emission analysis and an X-ray photoelectron spectrometer, the adsorbed Pd was found to be uniformly distributed on the surface of the prepared adsorbent and the existing species were Pd(II) and zero-valent Pd(0). Due to the desirable performances, facile preparation method, and abundant raw material source, the prepared adsorbent demonstrated a high application potential in the recovery of Pd(II) from simulated high-level liquid waste treatment.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2303-2308
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• 2009

A thiocyanate poly(vinyl chloride) (PVC) membrane electrode based on [1,2-bis(diphenylphosphino)ethane]dihalopalladium( II), [(dppe)$PdX_2$, X = Cl ($L^1$), X = I ($L^2$)] as active sensor has been developed. The diiodopalladium complex, [(dppe)$PdI_2](L^2$) displays an anti-Hofmeister selectivity sequence: $SCN^-\;>\;I^-\;>\;{ClO_4}^-\;>\;Sal^-\;>\;Br^-\;>\;{NO_2}^-\;>\;{HPO_4}^-\;>\;AcO^-\;>\;{NO_3}^-\;>\;{H_2PO_4}^-\;>\;{CO_3}^{2-}$. The electrode exhibits a Nernstian response (-59.8 mV/decade) over a wide linear concentration range of thiocyanate ($(1.0\;{\times}\;10^{-1}\;to\;5.0\;{\times}\;10^{-6}$ M), low detection limit ($(1.1\;{\times}\;10^{-6}$ M), fast response $(t_{90%}$ = 24 s), and applicability over a wide pH range (3.5∼11). Addition of anionic sites, potassium tetrakis[p-chlorophenyl] borate (KTpClPB) is shown to improve potentiometric anion selectivity, suggesting that the palladium complex may operate as a partially charged carrier-type ionophore within the polymer membrane phase. The reaction mechanism is discussed with respect to UV-Vis and IR spectroscopy. Application of the electrode to the potentiometric titration of thiocyanate ion with silver nitrate is reported.

• Journal of Oral Medicine and Pain
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• 제43권4호
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• pp.131-135
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• 2018

Purpose: To investigate the correlation between the amount of salivary metal ions released from fixed prostheses and the period of restoration insertion, and to evaluate the correlation between the type and amount of metal ions in saliva and oral lesions (OL). Methods: Based on the oldest prosthesis, we divided patients into two groups: more than 5 years (n=19) and less than 5 years (n=10). Patients were also divided into two groups by another criteria: the one with the presence (n=15), and the one with absence (n=14) of OL, and the amounts of metal ions were examined. Metal ions-gold (Au), copper, cobalt (Co), chromium (Cr), nickel, zinc, aluminum, palladium (Pd), tin, and platinum (Pt)-were measured using laser ablation microprobe inductively coupled plasma mass spectrometry. Results: Significantly higher quantities of Co, Pt, and Pd ions were released in patients with fixed prosthesis of more than 5 years (p<0.05). Measurement of the average amount of salivary metal ions was performed on patients with and without OL - Significantly higher amounts of Cr, Pd and Au ions were released in patients with OL (p<0.05). Conclusions: Old prostheses (${\geq}5years$) released metal ions, and among them were Co, Pt and Pd ions more than others. Patients with OL showed significantly higher levels of ion release, especially Cr, Pd and Au. There was a positive correlation between the amount of a certain kind of released metal ions, especially Pd, and the development of OL. Salivary Pd ion released from old prostheses could affect the pathogenesis of OL; therefore, long-term follow-up is important.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.417-420
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• 2012

This study is about reduction reaction making 2, 4-dinitrotoluene (2, 4-DNT) to 2, 4-toluene diisocyanate (2,4-TDI) with Pd/$SiO_2$. Catalytic systems based on Pd/$SiO_2$ at about $200^{\circ}C$ and under 100 bars of carbon monoxide. We studied the effect of pyridine on the yield of the TDI. TDI was not created without pyridine, but created with pyridine, at the reaction result. According to research, homogeneous synthesis of TDI with direct carbonylation, palladium and pyridine complexion is known to catalyze. When adding pyridine the reason of TDI synthesis is palladium leaching, ICP-AES was performed to confirm it. As a result, the proportion of Pd loaded in $SiO_2$ was decreased 52% than before, after the reaction by adding 20 vol% pyridine. Generating TDI by adding pyridine might be the effect of the complex ion, which is composed of leached palladium and pyridine.

• Journal of the Korean Chemical Society
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• 제39권4호
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• pp.244-251
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• 1995

The palladium(II) complexes(where, [Pd(L)2X2], L=isoxazole(isox), 3,5-dimethylisoxazole(3,5-diMeisox), 3-methyl, 5-phenylisoxazole(3-Me, 5-Phisox), and 4-amino, 3,5-dimethylisoxazole(4-ADI); X=Cl, Br] with isoxazole and its derivatives are investigated on antitumor activity by EHMO calculation. It is found that the net charge of the two halogen atoms in trans-isomers are greater than those in cis-ones, indicating that ionic character of Pd-X bond in trans-isomers is greater than that of cis-ones, and so dissociation of Cl- ion is easier than that of Br- ion in aqueous solution in body. Furthermore, it is found that the ${\sigma}MO$ energy of Pd(dx2-y2)-X(px) bond $(E{\sigma}(Pd-X))$ is higher than that of Pd(dx2-y2)-N(px) bond $(E{\sigma}(Pd-N))$ without exception, about all the complexes, and also the $E{\sigma}(Pd-X)$ of trans-isomers is higher than that of cis-isomers. From the above facts, the degree of dissociation in Pd-X bond would be related to antitumor activity. In fact, the linear equation of correlation coefficient 0.96 is fairly established between ${\Delta}E{\sigma}(N-X)(E\sigma(Pd-N)－E{\sigma}(Pd-X))$ and inhibitory activity coefficient, logIA.

• Bulletin of the Korean Chemical Society
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• 제23권12호
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• pp.1754-1758
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• 2002

Tetrathiafulvalene(TTF) reacts with $PdCl_2,Pd(NO_3)_2$ and $Pd(hfacac)_2$(hexafluoroacetylacetonate) in ethanol to give $(TTF)_{1.5}PdCl_2$ (1a), $(TTF)_3Pd(NO_3)_2$ (1b) and $(TTF)_4Pd(hfacas)_2$ nd (1c), respectively. $PdCl(TCNQ)_{2.5}{\cdot}CH_3OH(2a)$was obtained from the reaction of $PdCl_2$ with LiTCNQ in methanol via the partial replacement of $Cl^-$ in $PdCl_2$ by $TCNQ^-$anion, whereas the total substitution of the labile $NO_3^-$ in $Pd(NO_3)_2$ yielded pd(TCNQ)·$CH_3OH$ (2b). $Pd(hfacac)_2(TCNQ)_2\cdot3CH_3OH$ (2c) was obtained from $Pd(hfacac)_2$ and LiTCNQ in methanol. The prepared compounds were characterized by spectroscopic (IR, UV, XPS) methods and magnetic (EPR, magnetic susceptibility) studies. The powdered electrical conductivities (${\sigma}_{rt}$) of the prepared compounds at room temperature were about~$10^{-7}S{\cdot}cm^{-1}$. The effective magnetic moments were lass than the spin-only value of one unpaired electron and no EPR signals from Pd metal ions were observed in any of the compounds, indicating that the Pd ions were diamagnetic and the magnetic moments arose from$(TTF)_n$ or $(TCNQ)_n$ moieties. The experimental evidences revealed that the charge transfer had occurred form $(TTF)_n$ moiety to the central Pd metal ion in 1a, 1b and 1c. Thus the TTF donors were ions in 2a and 2b were diamagnetic Pd(II) oxidation state. In contrast, the Pd metal ion was oxidized to Pd(IV) state in 2c as a result of an addition of $TCNQ^-$anion to $Pd(hfacac)_2$ in methanol. The oxidation states of the Pd metal ions were confirmed using the x-ray photoelectron spectroscopy.