• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.502-507
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• 2016

This study was conducted to develop novel antimicrobial nano-composites, with the aim of fully utilizing antimicrobial properties of multi-walled carbon nanotubes (MWCNTs), nickel (Ni) and zinc oxide (ZnO). Ni coated-MWCNTs (Ni-CNT) were prepared and evaluated for their potential application as an antimicrobial material for inactivating bacteria. Field emission scanning electron microscopy (FE-SEM), and X-ray energy dispersive spectroscopy (EDS) were used to characterize the Ni coating and morphology of Ni-CNT. Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil) were employed as the target bacterium on antimicrobial activities. Comparing with the nitric acid treated MWCNTs and Ni-CNT which have been previously reported to possess antimicrobial activity towards S. aureus and E. coil, Ni-CNT/ZnO exhibited a stronger antimicrobial ability. The nickel coating was confirmed to play an important role in the bactericidal action of Ni-CNTs/ZnO composites. Also, the addition of ZnO to the developed nanocomposite is suggested to improve the antimicrobial property.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.776-783
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• 2010

Co and Ni catalysts supported on $Al_2O_3$ for partial oxidation of methane producing hydrogen were synthesized using impregnation to incipient wetness. The activities of these catalysts for the partial oxidation of methane was investigated at 1 atm and $CH_4/O_2=2.0$ in the temperature range of $450{\sim}650^{\circ}C$. The reaction activity of $Ni/Al_2O_3$ and $Co/Al_2O_3$ catalysts with different loading was investigated. And the beneficial effects of Ni addition to $Co/Al_2O_3$ and the promotional effects of Ce and La addition to $Ni/Al_2O_3$ and $Co/Al_2O_3$ were investigated. These catalysts were characterized by XRD and SEM/EDX. Comparing catalyst loadings, 10 wt% Co and 10 wt% Ni were found to be optimal at the experimental conditions. The 10 wt% $Ni/Al_2O_3$ and 10 wt% $Co/Al_2O_3$ catalysts in partial oxidation of methane showed $CH_4$ conversions and CO selectivity close to the thermodynamic equilibrium levels, but showed lower $H_2$ selectivity than equilibrium level. The addition of Ni to $Co/Al_2O_3$ exhibited higher $H_2$ selectivity but beneficial effect was not observed in the $CH_4$ conversion. Addition of Ce to $Co/Al_2O_3$ and addition of La to $Ni/Al_2O_3$ a improved the $CH_4$ conversion level and $H_2$ selectivity.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.85-88
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• 2007

고정층반응기에서 여러 가지 전이금속으로 치환된 하이드로탈사이트($[M_xMg_{6-x}Al_2(OH)_{16}(CO_3)^{2-}]{\cdot}H_2O;$ M: 전이금속(Ni, Mn, Co, Cu, Zn) x: 전이금속 치환비($x=0.5{\sim}6$))를 합성하고 이를 소성한 후 메탄의 부분산화 반응에 사용하였다. 반응 시 도입되는 $CH_4/O_2$비는 2로 하고 $VHSV=120,000cm^3/g$ h, 온도를 $500^{\circ}C$ 부터 $50^{\circ}C$ 간격으로 하여 $800^{\circ}C$까지 수행하였다. 실험결과 다른 전이금속들 중에서 니켈로 치환된 촉매가 대체적으로 부분산화반응을 촉진시키는데 좋은 것으로 나타났으며, 실험 결과 니켈의 hydrotalcite 중의 치환비(x)에 따른 차이는 별로 없었다.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.270-274
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• 2015

We develop advanced oxidation processes for the treatment of spent electroless nickel plating solution. Apart form recovering nickel by leaching and enrichment, more emphasis is placed on rendering the waste water recyclable via oxidizing phosphite and hypophosphite into phosphate which can then be precipitated easily. $UV/H_2O_2$ process is employed and the conversion efficiency of COD and $PO_4-P$, and $H_2O_2$ consumption are analyzed. Furthermore, the $UV/H_2O_2/O_3$ process in conjunction with $O_3$ generator enables us to not only save the treatment time by 6 hours but also reduce $H_2O_2$ consumption by 30%.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.4
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• pp.9-17
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• 2014

In this study, in order to improve the ignitability of high energy aluminum powder, natural oxide films (alumina) were chemically removed, and instead nickel coat was applied. We used an electroless plating for nickel coating and confirmed quantitatively and qualitatively a time-dependent degree of nickel coating through analysis of surface by SEM/EDS. We also conducted element analysis by XRD and thermal properties by TGA/DSC in air oxidizer environment. There results explained the ignition enhancement mechanism of the nickel-coated aluminum powder in air. The difference between coated and un-coated aluminum powder, the effectiveness of coated powder has better ignitability.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.178-182
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• 2003

The oxygen reduction and NiO dissolution behaviors in Li-Na-K three component carbonate melts have been investigated with various compositions through electrochemical and chemical ways. The oxygen reduction currents and NiO solubilities were measured at $650^{\circ}C$ and atmospheric condition in Li-Na-K =47.4-32.6-20, 60-20-20, 50-40-10, $40-40-20 mol\%$ carbonate melts. The oxygen reduction currents showed dependence on the composition, indicating oxygen solubility is a function of carbonate composition. At the composition of $ Li-Na-K=50-40-10 mol%$, a broader peak was observed, suggesting different oxygen reduction mechanism probably prevails in this composition. In contrast, insignificant differences of NiO solubility were obtained among the compositions.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.125.1-125.1
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• 2007

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.2
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• pp.89-97
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• 2010

$Al_2O_3$, $TiO_2$, $ZrO_2$, $Al_2O_3-TiO_2$, $Al_2O_3-ZrO_2$, 및 $TiO_2-ZrO_2$ 혼합 산화물을 지지체로 한 Ni 기반 혼합 산화물을 졸-겔법으로 제조하였다. 제조된 혼합 산화물은 1173K에서 열처리 한 후 구조적 특성 변화를 전자현미경 및 X-선 회절 분석을 이용하여 관찰하였으며, 수소를 이용한 승온 환원(TPR; temperature-programmed reduction) 실험을 통하여 1173K 까지 각 시료들의 환원 피크를 비교 고찰하였다. $Al_2O_3$ 또는 $TiO_2$ 가 혼합된 시료의 경우 1173K 에서의 열처리 후 니켈 알루미네이트 또는 니켈 티타네이트와 같은 새로운 결정상의 생성이 관찰되었으나 $ZrO_2$가 혼합된 경우에는 새로운 결정상의 생성이 관찰되지 않았다. TPR 결과에 의하면, $Al_2O_3$ 또는 $TiO_2$를 혼합된 시료의 경우 벌크 NiO의 TPR 결과와는 달리 생성된 새로운 결정상에 기인한 여러 개의 환원 피크가 나타났으나 $ZrO_2$를 혼합한 경우 벌크 NiO와 비슷한 환원 피크를 보였다. TPR 결과를 기초로 Arrhenius plot 으로부터 각 혼합 산화물들의 수소 환원 활성화 에너지를 도출하였다. $ZrO_2$를 지지체로 사용하는 경우 다른 혼합 산화물들보다 지지체로서 안정한 혼합 산화물상을 형성한다는 것을 지시하듯이 상대적으로 가장 낮은 활성화 에너지를 나타냈다.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.533-539
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• 2013

The electrochemical corrosion and passivation of Ni rotating disk electrod in borate buffer solution was studied with potentiodynamic and electrochemical impedance spectroscopy. The mechanisms of both the active dissolution and passivation of nickel and the hydrogen evolution in reduction reaction were hypothetically established while utilizing the Tafel slope, impedance data, the rotation speed of Ni-RDE and the pH dependence of corrosion potential and current. Based on the EIS data, an equivalent circuit was suggested. In addition, carefully measured were the electrochemical parameters for specific anodic dissolution regions. It can be concluded from the data collected that the $Ni(OH)_2$ oxide film, which is primarily formed by passivation, is converted to NiO by dehydration under the influence of an electrical field.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.357-362
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• 1998

PWR 정지시 일차계통 수화학 제어의 주요대상은 계통표면에 침적된 부식생성물의 주성분인 비화학양론적 니켈(코발트)페라이트로서, 산성-환원 단계에서 용존수소에 의해 Ni$^{\circ}$ (또는 Co$^{\circ}$)로 환원되고 산성-산화 단계에서 용존산소에 의해 Ni$^{2+}$ (또는 CO$^{2+}$)로 산화되어 이온교환기에 의해 제거된다 본 연구에서는, 니켈 및 코발트 산화물의 25~300 $^{\circ}C$ 환원 또는 산화반응 시 표준자유에너지의 변화 및 용존수소 또는 용존산소의 요구농도를 계산하여, 원자로 정지시 일차계통수 용존 기체의 제어조건을 고찰하였다. 산성-환원 단계의 냉각재 온도인 300~82$^{\circ}C$ 범위에서 용존수소가 충분할 경우 열역학적으로 $^{58}$ Co(또는 $^{60}$Co)Fe$_2$O$_4$$\longrightarrow$Co의 역반응이 억제되므로서 노심외 계통부위 침적이 감소될 수 있기 때문에, 용존수소를 온도에 따라 요구농도 곡선 위로 약간 높게 유지하는 것보다 25~50 cc/kg-$H_2O$로 유지하는 방식이 바람직한 반면, 용존산소를 제공하는 과산화수소 농도가) 2.7 ppm일 때 NiFe$_2$O$_4$$\longrightarrow$Ni$_2$O$_4$(+$\alpha$-Fe$_2$O$_3$) 반응이 일어날 수 있기 때문에, 산성-산화 단계에서는 과산화수소의 냉각재 농도를 이보다 낮게 유지하는 것이 바람직하다.