• Corrosion Science and Technology
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• 제17권5호
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• pp.225-230
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• 2018

The effects of birch sap, a possible natural corrosion inhibitor, on the corrosion behavior of steel in chloride solution were investigated. The corrosion rate was significantly reduced by the addition of 1~5 mL of birch sap to 500 mL of 3wt% NaCl or 3wt% $CaCl_2$ solution. A remarkable increase in the pitting potential in NaCl solution was observed by the addition of birch sap although it was almost constant in $CaCl_2$ solution. The corrosion rate of steel in both NaCl and $CaCl_2$ birch sap solution without addition of water was higher compared to that of aqueous solution without birch sap as the pH of the birch sap was 4.0. The presence of organic compounds like, fructose, galactose, glucose, and palmitic acid in the birch sap are thought to be adsorbed effectively on the metal surface, which provided corrosion protection. However, the inorganic elements including Na, Ca, K, Mg, Mn, S, etc. present in the birch sap exhibited no role in corrosion inhibition.

• 전기학회논문지
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• 제59권11호
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• pp.2026-2031
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• 2010

The electrical characteristics of galvanic cell which is composed of the cathode electrode(graphite, carbon and copper) and the anode electrode(Zn and Mg) were investigated. For this research as electrolyte 2~12 wt% NaCl aqueous solution were used. At graphite cathode electrodes which use Zn and Mg with the anode electrode, the open circuit voltage was 1.3V most highly. The maximum output power increased as the electrolyte concentration increased, due to a increase in ion density. When Zn and Mg with the anode electrode, the maximum output power respectively was evaluated as 2.2mW and 5.5mW about the graphite cathode electrode in the NaCl 4wt%. The research results indicated that the output power of cell which is composed with graphite with the cathode and Mg with the anode was most excellent and the efficiency of the cell could be enhanced by increasing the electrolyte concentration.

• 한국주조공학회지
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• 제36권4호
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• pp.117-125
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• 2016

The effects of the Zn content on the microstructure and corrosion behavior in 1M NaCl solution were investigated in Mg-(0~6)%Zn casting alloys. The MgZn phase was scarcely observed in the Mg-1%Zn alloy, while the Mg-(2~6)%Zn alloy consisted of ${\alpha}$-(Mg) and MgZn phases. With an increase in the Zn content, the amount of the MgZn phase was gradually increased. Immersion and electrochemical corrosion tests indicated that the Mg-1%Zn alloy had the lowest corrosion rate among the alloys, and a further increase in the Zn content resulted in the deterioration of the corrosion resistance. Microstructural examinations of the corroded surfaces and EIS analyses of surface corrosion films revealed that the best corrosion resistance at 1%Zn was associated with the absence of MgZn phase particles in the microstructure and the contribution of Zn element to the formation of a protective film on the surface. A micro-galvanic effect by the MgZn particles led to the increased rate of corrosion at a higher Zn content.

• 한국분말재료학회지
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• 제11권4호
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• pp.322-327
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• 2004

Ultrafine titanium carbide particles were synthesized by the reaction of liquid-magnesium and vaporized TiCl$_{4}$+C$_{x}$Cl$_{4}$(x = 1 and 2) solution. Fine titanium carbide particles with about 50 nm were successfully produced by combining Ti and C atoms released by chloride reduction of magnesium, and vacuum was then used to remove the residual phases of MgCl$_{2}$ and excess Mg. Small amounts of impurities such as O, Fe, Mg and Cl were detected in the product, but such problem can be solved by more precise process control. The lattice parameter of the product was 0.43267 nm, near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl$_{4}$+C$_{2}$Cl$_{4}$and Mg was found to 69 kJ/mole, which was about half value against the use of TiCl$_{4}$+CCl$_{4}$, and such higher reactivity of the former contributed to increase the stoichiometry until the level of TiC$_{0.96}$ and decrease the free carbon content below 0.3 wt.%.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.59-65
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• 2023

Sodium hydroxide solutions are often employed as sterilization agents in the pharmaceutical industry. Here, the chloride content is considered as a critical impurity. In this study, an electrochemical method was developed to remove chloride ions (Cl^-) through the oxidative deposition of AgCl on a Ag anode. The Cl^- content in the commercially available 50% w/w NaOH solution employed was approximately 100 mg Cl^-/kg NaOH. As the OH^- content is approximately 18,000 times higher than the Cl^- content, the formation of AgCl may be expected to be thermodynamically less favorable than the formation of Ag₂O. However, activation energies for AgCl and Ag₂O formation have been reported to be approximately 3.8 and 31.2 kJ/mol, respectively, and indicate that AgCl formation is favored. AgCl can be selectively produced by controlling the anode potential. Here, the Cl^- concentration was reduced to less than 50 mg Cl^-/kg NaOH when an anode potential of 0.18 or 0.19 V vs. Hg/HgO (reference electrode) was applied for one hour at 50℃. XRD analysis and visual monitoring of the Ag anode confirmed the oxidative deposition of AgCl on the anode surface as well as the electrochemical desalination of the concentrated NaOH solution.

• 멤브레인
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• 제29권6호
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• pp.355-361
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• 2019

본 연구에서는 기존의 CDI (capacitive deionization)를 이용해 산업 폐수에 함유되어있을 수 있는 바륨 이온 제거에 관해서 연구하였다. Feed 용액은 30 mg/L의 BaCl₂ (barium chloride dihydrate) 수용액을 사용하였고, 유속은 10 mL/min 설정하였다. 흡착 조건을 1.2 V에서 3, 5, 7분으로, 탈착 조건은 각각 -1, -1.5, -2 V 및 1, 2, 3분으로 다양하게 조정하여 가장 효율이 높은 조건을 선정하는 실험을 진행하였고, 그 결과 흡착 1.2 V/7분 탈착 -1 V/1분의 조건에서 64.4%의 바륨 이온 제거효율을 나타내었다. 동일한 실험 조건으로 바륨과 같은 농도인 30 mg/L NaCl 수용액에 대하여 CDI의 제거효율과 비교 분석한 결과 흡착 1.2 V/7분 탈착 -1 V/1분의 조건에서 69.9%의 제거효율을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제18권2호
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• pp.213-217
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• 1997

Magnesium reduction of Mo(N-C6H3-2,6-i-Pr2)2Cl2(DME) in the presence of trimethylphosphine led to a mixture of Mo(N-C6H3-2,6-i-Pr2)(PMe3)2Cl3, 1, and Mo2(PMe3)4Cl4, 2. In solution 1 is slowly air-oxidized to Mo(N-2,6-i-Pr2-C6H3)(OPMe3)(PMe3)Cl3, 3. 1 is chemically inert to carbon nucleophiles (ZnMe2, ZnEt2, AlMe3, AlEt3, LiCp, NaCp, TlCp, NaCp*, MeMgBr, EtMgBr), oxygen nucleophiles (LiOEt, LiO-i-Pr, LiOPh, LiOSPh), and hydrides (LiBEt3H, LiBEt3D). Crystal data for 1: orthorhombic space group P212121, a=11.312(3) Å, b=11.908(3) Å, c=19.381(6) Å, Z=4, R(wR2)=0.0463 (0.1067). Crystal data for 2: monoclinic space group Cc, a=18.384(3) Å, b=9.181(2) Å, c=19.118(3) Å, b=124.98(1)°, Z=4, R(wR2)=0.0228 (0.0568). Crystal data for 3: orthorhombic space group P212121, a=11.464(1) Å, b=14.081(2) Å, c=16.614(3) Å, Z=4, R(wR2)=0.0394 (0.0923).

• 한국양식학회지
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• 제13권3호
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• pp.187-191
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• 2000

삼투질농도가 감성돔(Acanthopagrus schlegeli) 정자의 운동성에 미치는 영향을 연구하였다. 감성돔 정자는 정장과 등장인 삼투질농도에서 운동성이 억제되었으나, 전해질(NaCl, KCl, $CaCl_2$, $MgCl_2$) 및 비전해질(mannitol, glucose, fructose, sucrose) 희석액의 삼투질농도가 증가할 때, 운동성을 획득하였다. 희석액의 삼투질농도에 의한 정자운동지수(SMI)의 변화는 포물선을 그렸다 모든 희석액에서 SMI는 해수의 삼투질농도와 유사한 약 1,000 mOsm/kg에서 가장 높았고 그 이상에서는 다시 낮아졌다. 비록 정자의 운동성이 희석액의 삼투질농도에 의해 유발되고 해수와 비슷한 농도의 고장인 희석 액에서 SMI가 가장 높았지만, 고장이나 저장의 희석액에 정자를 노출시키는 것은 정자의 운동성 감소를 유발하였고 생존에 유해하였다.

• 자원리싸이클링
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• 제23권6호
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• pp.22-29
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• 2014

네오디뮴 폐자석 침출액으로부터 희유금속인 네오디뮴을 회수하는 연구와 함께 네오디뮴과 같이 침출되는 철의 부가가치를 높이는 연구가 필요하다. 본 연구에서는 네오디뮴과 같이 침출되는 철의 유용자원화를 위한 기초연구로 철 나노분말을 제조하는 실험을 수행하였다. 본 연구는 $FeCl_3$ 용액을 철 분말 원료로, 분산제는 $Na_4P_2O_7$와 Polyvinylpyrrolidone를 이용하였고, 환원제로는 $NaBH_4$, 철 나노분말 핵생성 촉진제 seed로 염화팔라듐을 사용하였다. 제조한 철 나노분말을 XRD, SEM을 이용하여 분말의 형상 및 크기를 분석하였다. Fe와 $NaBH_4$의 몰 비를 1 : 5로 조절하여 철 분말을 제조하였으며, 이 때 철 분말은 구형이었으며, 입도는 약 50 ~ 100 nm 였다. 분산제 $Na_4P_2O_7$의 경우 100 mg/L에서 철 이온의 제타포텐셜이 음의 값을 가졌고, $FeCl_3$ 과 PVP와 Pd의 질량비 1 : 4 : 0.001에서 분산이 양호하고, 입도가 100 nm 인 철 나노분말을 합성하였다. 같은 반응 조건에서 폐 Nd 침출액의 Fe 이온을 pH를 조절하여 슬러리화한 후 실험을 진행한 결과, pH 9에서 구형의 철 분말을 합성할 수 있었으며, 20 L 이상의 Scale-up 공정에서는 분산제 없이 환원제로 175 nm 크기의 철 분말을 합성할 수 있었다.

• 한국표면공학회지
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• 제51권5호
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• pp.325-331
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• 2018

Calcium carbonate($CaCO_3$) films were formed by an eco-friendly electro-chemical technique on steel substrates in synthesized distilled water solutions containing $NaHCO_3$, $CaCl_2$ and $MgCl_2$ with different ratio respectively. It was investigated to confirm the effect of $Mg^{2+}$ concentration by Scanning Electron Microscopy(SEM), Energy Dispersive x-ray Spectroscopy(EDS) and X-Ray Diffraction(XRD) respectively. From an experimental result, only calcite crystals were found in solution containing no $Mg^{2+}$. By increasing concentration of $Mg^{2+}$, deposition rate decreased and crystal structure was transformed form calcite to aragonite. In case of including $MgCl_2$ 300mM in synthesized solutions containing $NaHCO_3$, $CaCl_2$ 60mM, it was showed over the 90% of aragonite contents which have quite high deposition rate of aragonite. Also, it was confirmed that $Mg^{2+}$ acted as inhibitor on the films which made transforming from calcite to aragonite.