• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.334-336
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• 2003

Recently, considerable researches have been focused to find out inexpensive sorbents. for removal of heavy metals in aquatic environments. In particular, various natural materials including geologic media have been attractive. In order to evaluate the applicability of the scoria taken from the Jeju island, Korea, to remove Zn(II) from aqueous solutions, the kinetic sorption experiments were performed in this study. The batch-type kinetic sorption tests were carried out under different conditions, such as different initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. The results indicated that the removal of Zn(II) by scoria increased with decreases in initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. However, the sorption capacity of the scoria decreased with increasing amount of the scoria. The sorption behavior of Zn(II) onto scoria seemed to be mainly controlled by cation exchange.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.302-305
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• 2002

Scoria is a bomb-sized, generally vesicular pyroclast that is red or black in color and light in weight. In this study, scoria from Cheju was examined for the use as a sorbent. It is composed of plagioclase, olivine, hornblende, pyroxene, and glass, with an average composition of 49.84% SiO$_2$, 14.07% A1$_2$O$_3$, End 9.14% Fe$_2$O$_3$. Studies on kinetic isotherm sorption of Zn(II) onto scoria under various parameters such as initial zinc concentration, particle size, and adsorbent/adsorbate ratio were carried out using an agitated batch. The results suggest that the smaller scoria size and the larger adsorbent/adsorbate ratio produce the higher degree of Zn(II) removal. More effective removal also appears at lower initial Zn concentration. The sorption behavior of Zn(II) onto scoria seems to be mainly controlled by cation exchange. Studies on equilibrium isotherm sorption of other heavy metals (Pb, Cu, Cd) onto scoria were also conducted and compared with those onto powdered activated carbon (PAC) and non-organic matter scoria (NOS), The results suggest that the Cheju scoria has the slightly higher sorption capability than PAC and NOS, and the order of the effective sorption onto scoria and PAC is Pb > Cu > Zn > Cd. The monometal sorption onto scoria is more stronger than the competitive sorption.

• Asian-Australasian Journal of Animal Sciences
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• 제32권1호
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• pp.63-71
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• 2019

Objective: The aim of the study was to investigate the effect of zinc-bearing palygorskite (Zn-Pal) on rumen fermentation by in vitro gas-production system. Methods: In trial, 90 incubators were evenly divided into five groups: control (0% Zn-Pal), treatment I (0.2% Zn-Pal), treatment II (0.4% Zn-Pal), treatment III (0.6% Zn-Pal), and treatment IV (0.8% Zn-Pal). The contents of zinc for treatments were 0, 49, 98, 147, 196 mg/kg, respectively. The main chemical composition and microstructure of Zn-Pal was investigated by X-ray diffraction. The physicochemical features were evaluated by Zeta potential analysis, cation-exchange capacity, ethylene blue absorption and specific surface area (the Brunauer-Emmett-Teller method). In vitro gas production (GP) was recorded at 3, 6, 9, 12, 18, 24, 36, 48, 60, and 72 h incubation. Incubation was stopped at 0, 6, 12, 24, 48, and 72 h and the inoculants were tested for pH, microbial protein yield (MCP), $NH_3-N$, volatile fatty acids (VFAs), lipopolysaccharide (LPS). Results: The results showed that the GP in the treatment groups was not significantly different from the control groups (p>0.05). Compared to the control group, pH was higher at 24 h, 48 h (p<0.05), and 72 h (p<0.01) (range 6 to 7). The concentration of $NH_3-N$ in the three treatment groups was higher than in the control group at 24 h (p<0.01), meanwhile, it was lower at 48 h and 72 h (p<0.01), except in the treatment IV. The concentration of MCP in treatment I group was higher than in the control at 48 h (p<0.01). Compared with control, the LPS concentration in treatment III became lower at 12 h (p<0.05). Total VFAs in treatments were higher than in the control at 24 h, 48 h (p<0.05). Conclusion: These results suggest that the addition of Zn-Pal can improve the rumen fermentation, especially when adding 0.2% Zn-Pal.

• 상하수도학회지
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• 제35권6호
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• pp.465-476
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• 2021

Scale and rust generation in water pipes is a common phenomenon when cast iron water pipes have been used for a long time. A physical water treatment device is known among various means for suppressing rust in a water pipe, and a zinc ionization device for putting zinc metal into a pipe and emitting the zinc cation into water is one of such devices. This research measured the amount of zinc ion generated, which is known to exhibit an effect of inhibiting rust and scale generation in a pipe, and examined the scale and rust inhibition effect of the ionization device installed for ground or building water supply. In the case of distilled water, the concentration of zinc ion increased by circulating water in the ionization device several times, and it was verified to be hundreds of ㎍/L, and in the case of discharging ground or tap water, it was verified to be tens of ㎍/L. In addition, a verification pipe was installed to confirm the change inside the pipe before and after installation of the zinc ionization device, and the internal condition of the pipe was observed 3 months to several years after installation. It was confirmed that the corrosion area of the surface of the pipe was no longer increased by installing a corrosion inhibitor, and if the pipe was already filled with corrosion products, the amount of corrosion products gradually decreased every year after installation. The phenomenon of fewer corrosion products could be interpreted as expanding the space in the pipe due to the corrosion product as Fe₂O₃ adhered to the inner surface of the pipe and turned into a smaller black Fe₃O₄. In addition, we found that scale such as CaCO₃ together in the corrosion by-products gradually decreased with the attachment of the ionization device.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.87-105
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• 1991

The purpose of this experiment was to measure the leaking and solubility of commonly used dental restorative materials - Silux plus (CS), Hi-pol (CH), Clearfil F-II, Fissureseal (FS), Glass-Ionomer cement Fuji Type II (GI), Amalgam Cavex 68 (AM), Zinc Phosphate Cement (ZP) and gutta-percha (GP) and investigate the relation between the solubility and marginal leakage. Disc-shape specimens were fabricated with each material and dipped into deionized water, 0.01M lactic acid and 0.005M KOH solution, thus the total ionic concentrations in each solution was measured with ion chromatograph after 1, 3, and 7 days, respectively. For the solubility test, each specimen was immersed in 0.001M and 0.01M lactic acid for 24 hours, respectively and total weight loss was calculated. Also, Zn leaking through the margin of restorations was measured. The obtained results were as follows: 1. The amounts of eluted ion from the eight materials were most in 0.01M lactic acid and least in deionized water. 2. Of the eight materials, the fluoride release was greatest for glass ionomer cement (GI) in 0.01 M lactic acid after 7 days. 3. In analysis of the divalent cation, Mg was eluted most for zinc phosphate cement (ZP) and Ca for Clearfil F-II (CF) in 0.01M lactic acid after 7 days. 4. In analysis of transition metals, Cu and Zn were detected only. 5. The solubility rate of eight materials was greater in 0.01M lactic acid than in 0.001M for 24 hours, for zinc phosphate cement (ZP) the rate was greatest (5.4%) in 0.001M lactic acid, and amalgam least (0.01%). 6. The Zn concentration of restorative material with Z.P.C base was greater in 0.01M lactic acid than in 0.001M lactic acid.

• 마이크로전자및패키징학회지
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• 제30권3호
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• pp.94-101
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• 2023

투명 전도성 산화물(TCO)를 대체할 수 있는 대표적인 물질로 알려진 ZnO는 3.37 eV의 bandgap과 60 meV의 exciton binding energy를 가진 반도체 물질이다. 본 연구에서는 투명 전극으로 사용하기 위한 높은 전기적 특성을 확보하기 위해 원자층 증착법을 기반으로 양이온과 음이온의 단일 및 이중 도핑에 따라 성장한 ZnO 박막을 제작하였다. 3가 양이온 Al, Ga과 음이온 F이 단일 및 이중 도핑된 ZnO 박막의 구조적, 광학적 특성 및 전기적 특성을 확인하였다. 단일 도핑의 경우, ZnO에 donor로 작용하는 Al, Ga, F에 의해 캐리어 농도가 도핑 전에 비해 증가하였고 근자외선 영역에서의 band-edge absorption이 증가하는 것을 확인하였다. 단일 도핑 중에서는 F이 ZnO 내 산소 공공 자리에 passivation 되면서 높은 mobility와 함께 가장 높은 전도도를 보였다. 이중 도핑의 경우, 각 원소들의 도핑 효과가 더해지면서 단일 도핑에 비해 높은 전기적 특성을 보였다. 결과적으로 Ga-F에 비해 Al-F 도핑 시 ionic radius 차이에 의한 lattice distortion 감소 및 delocalized 된 전자 상태의 증가로 가장 낮은 비저항 값을 보였으며 PDOS 분석을 통한 시뮬레이션 데이터로 측정 값과 일치하는 결과를 확인했다.