• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.210.1-210.1
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• 2014

The hexagonal boron nitride (h-BN) sheet, a 2D material like graphene sheet, is comprised of boron and nitrogen atoms. Similar to graphene, h-BN sheet has attractive mechanical properties while it has a wide band gap unlike graphene. Recently, many experimental groups studied the growth of single BN layer by chemical vapor deposition (CVD) method on the copper substrate. To study the initial stage of h-BN growth on the copper surface, we have performed density functional theory calculations. We investigate several adsorption sites of a boron or nitride atom on the Cu surfaces. Then, by increasing the number of adsorbed B and N atoms, we study formation behaviors of the BN flakes on the surface. Several types of BN flakes atoms such as triangular, linear, and hexagonal shapes are considered on the copper surface. We find that the formation of the BN flake in triangular shape is most favorable on the surface. On the basis of the theoretical results, we discuss the growth mechanism of h-BN layer on the copper surfaces in terms of its shapes in the initial stage of growth.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.5
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• pp.351-355
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• 2014

In recent years, biochar has received much attention as soil amendment, enhancing soil fertility and reducing toxicity of heavy metals with its large specific surface area and high pH. Biochar has also the effect of alleviating global warming by carbon sequestration from recycling organic wastes by pyrolysis. However, scattering of fine particles of biochar is a hindrance to expand its use from human health point-of-view. Alginate, a natural polymer without toxicity, has been used for capsulation and hydrogel fabrication due to its cross-linking nature with calcium ion. In this study, the method of cross-linkage between alginate and calcium ion was employed for making dust-free biochar bead. Then an equilibrium adsorption experiment was performed for verifying the adsorption effect of biochar bead on heavy metals (cadmium, copper, lead, arsenic, and zinc). Results showed that biochar bead had effects on adsorbing heavy metals, especially lead, except arsenic.

• Journal of Powder Materials
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• v.12 no.6 s.53
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• pp.441-446
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• 2005

The copper oxide nano powders were synthesized by levitational gas condensation (LGC) method, and were applied to catalyst to fabricate 3,4-dihydropyrimidin-2-(1H)-one. Processes of adsorption of Biginelli reaction reagents on the copper nanooxide surface $Cu_2O{\circ}CuO$ were studied by IR-spectroscopy. It was shown that benzaldehyde coordination, acetoacetic ether on the oxide surface is carried out with participation of carbonyl fragments, urea by N-H bonds which affects positively on the reagents reactivity.

• Journal of the Korean Wood Science and Technology
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• v.37 no.2
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• pp.137-140
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• 2009

Chromated copper arsenate (CCA), a long history of successful preservative, have raised environmental concerns. Adsorption characteristics of domestic soils for chromium, copper, and arsenic were assessed by measuring distribution coefficient ($K_d$) values of these metal components in a laboratory scale. The results revealed that $K_d$ values were higher in chromium, followed by arsenic and copper in soil matrix. Different soil matrixes resulted in varying mobilities of CCA components. The values of $K_d$ for all three metals increased with organic matter contents. The results suggest that the mobility of metal components may be very limited to the surface area adjacent to CCA-treated wood due to their fairly large distribution coefficient ($K_d$). However, the metal components would be persistent and accumulated in the soil, resulting in high chemical concentration in service area of treated wood.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.58-64
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• 2013

This study proposed a low temperature hydrothermal carbonization to treat and recycle sewage sludge and determined the optimal conditions for the biochar production. The physical and chemical properties of biochar were analyzed and its sorption capacity for heavy metals was evaluated. To produce biochar, 50 g of sewage sludge was heated at 220, 230, and $240^{\circ}C$ for 1, 2, 3, 5, 8, and 10 hours in a reactor. The optimal conditions to produce biochar was $230^{\circ}C$ and 8 hours. Sorption capacity tests were conducted for arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn) and nickel (Ni). Among them, lead was shown the highest heavy metal adsorption efficiency of biochar, followed by copper, cadmium, zinc, and nickel, but arsenic was hardly adsorbed overall.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.416-422
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• 1993

As a result of adsorbing phthalocyanine (metal free, ${\alpha}\;and\;{\beta}$-Cu) on zinc oxide in aqueous solution using nonionic surfactant, all of the added dye was adsorbed and Na salt of sulfonated phthalocyanine showed the Langmuir monolayer adsorption. To analyze the effect of adsorption on zinc oxide, photovoltage was measured using surface photovoltmeter. The high photovoltaic effect was observed at intrinsic wavelength of zinc oxide and wavelength of adsorbed phthalocyanine dye. Metal free phthalocyanine, ${\alpha}$-copper phthalocyanine and ${\beta}$-copper phthalocyanine showed the highest photovoltaic effect when the percentage of coverage (${\theta}_{BET}$) for zinc oxide is about 80, while sulfonated phthalocyanine showed the highest photovoltaic effect when the percentage of coverage for zinc oxide is about 30.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.48-56
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• 2018

A potassium copper hexacyanoferrate (KCuHCF) embedded magnetic hydrogel bead (HCF-Mbead) was synthesized via a facile double crosslinking methods of $Fe^{3+}$ ionic binding and freeze-thaw for effective $Cs^+$ removal. The HCF-Mbead had a hierarchical porous structure facilitating fast access of $Cs^+$ ions to embedded active sites. The adsorbent showed enhanced $Cs^+$ removal properties in terms of capacity (69.2 mg/g), selectivity ($K_d=4{\times}10^4mL/g$, 1 ppm $Cs^+$ in seawater) and stability (>99.5% removal in pH 3~11) with rapid magnetic separation. This study further opens the possibility to develop an efficient material that links the integration of adsorption and recovery.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.29-35
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• 2009

In this study, the effect of pH and temperature on the adsorption behavior of acid mine drainage (AMD) on coal mine drainage sludge (CMDS) has been investigated during the treatment of coal mine drainage (CMD) by electrical purification method. The pH$_{zero\;point\;charge}$ (pH$_{zpc}$) of CMDS was 5. The removal ratio of copper, zinc, cadmium, iron were increased according to the increase of pH value. The adsorption amount of copper showed 0.64 mg g$^{-1}$ sludge. It was independent of pH value. The adsorption amount of the other metals showed l.l times when pH was 3. The adsorption amount of chromium was a little bit increased at the pH value higher than 7 due to a small amount of the chromium was eluted as $Cr(OH)_6^{3-}$. The amount of metals' absorption were decreased according to temperature was increase at pH value was 3. The selectivity order was Cd>Fe > Zn > Cu. The amount of absorption showed q$_{max}$ Cu 2.747 mg g$^{-1}$ andZn 2.525 mg g$^{-1}$ when pH value higher than 5. It was independent of temperature.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.501-508
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• 2009

In this study, the characteristics of granular activated carbon (GAC) supported metal was investigated in an area influenced by flame discharge and temperature variation during irradiating microwave. The modified GAC was formulated by impregnating metal hydroxides of nickel (Ni/GAC), barium (Ba/GAC), copper (Cu/GAC), zinc (Zn/GAC), cobalt (Co/GAC) and lanthanum (La/GAC). Ba/GAC was selected as it showed lack of spark discharge and temperature increasing aspects. Comparison of adsorption and desorption amount of GAC and Ba/GAC showed that adsorption and desorption rate of the GAC were higher than those of Ba/GAC. The results show that the presence of barium can decrease adsorption/desorption rate because of plugging pore of GAC. Toluene regeneration rate of Ba/GAC was better than that of GAC due to barium loading. Finally, GAC with barium can be controled a rapid increasing temperature and spark discharge, increased the regeneration rate of toluene during desorption by irradiating microwave.

• Textile Coloration and Finishing
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• v.8 no.6
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• pp.40-46
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• 1996

In order to investigate a practical application of fibrous absorbents to transition metals such as copper, nickel, cobalt, chrome, and iron, amidoximated fiber as a particular class of solid chelate agents were prepared from acrylic fibers treatment with hydroxylamine. The adsorption mechanisms of metal ions onto amidoximated acrylic fibers and their complexes were studied. Amidoximation of acrylic fiber with hydroxylamine is found to be first-order reaction, followed by the disappearance of infrared adsorption peaks due to nitrile groups of acrylic fibers. The uptake of metal ions onto amidoximated acrylic fiber is increased with temperature raising and the adsorption is also depended on pH of the soiutions. About 70% of metal ions can be recovered from aqueous solutions of Ni(II), Co(II), Cr(III), and Fe(II) on the concentration below 5x 10$^$^{-4}$ in the range of pH 2.1~10.0. Transition metals are adsorbed to form complex with amidoxime group by the ligand sites such as C=N, NH, NO, NHOH.OH.