• Korean Chemical Engineering Research
• /
• v.55 no.6
• /
• pp.785-790
• /
• 2017

To collect zinc, Fe and Zn in spent pickling solution were extracted by using TBP (tributyl phosphate), and Zn was recovered from extracted solution to zinc oxalate particles by oxalic acid solution. The reusability of TBP solvent was also tested. The distribution coefficient of Zn was not affected by the concentration of Fe in spent pickling solution, almost constant with the values of 7.12~9.31 when extracted by TBP solvent. It was found that the extraction capacity of TBP solvent for Zn is higher than that for Fe. The extraction efficiency of Zn was higher than 95%, while most of Fe was left in aqueous phase. After the recovery, the used TBP solvent could be repeatedly reused for the extraction of Zn up to eight times. XRD analysis showed that zinc oxalate ($ZnC_2O_4$ $2H_2O$) was formed from the reaction of Zn-TBP and oxalic acid. From the results of SEM analysis, the formation of zinc oxalate particle was strongly affected by the concentration of oxalic acid. In summary, Zn in spent pickling solution was successfully separated and recovered with TBP solvent and oxalic acid solution, respectively.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.257-260
• /
• 2007

In this study, $CuInSe_{2}$ (CISe) and $CuInZnSe_{2}$ (CIZSe) thin films were prepared on Corning 1737 glass by radio frequency (RF) magnetron sputtering from binary chalcogenide mixed powder targets. The targets were initially prepared by mixing appropriate weights of CuSe, InSe powder and various ZnSe contents. From the film bulk analysis result, it is observed that Zn concentration in the films increases proportionally with the addition of ZnSe in the sputtering targets. Under optimized conditions, CISe and CIZSe thin films grow as a chalcopyrite structure with strong (112), (220/204) and (312/116) reflections. Films are found to exhibit a high absorption coefficient of $10^{4}$ $cm^{-1}$. An increasing of optical band gap from 1.0 eV (CISe) to 1.25 eV (CIZSe) is found to be proportional with an increasing of Zn concentration as expected. All films have a p-type semiconductor characteristic with a carrier concentration in the order of 1014 $cm^{-3}$, a mobility about $10^{1}$ $cm^{2{\cdot}-1}{\cdot}s^{-1}$ and a resistivity at the range of $10^{2}-10^{6}$ W${\cdot}$m.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.11a
• /
• pp.270-273
• /
• 2007

In this report, Indium-free and Indium-reduced thin film materials for solar absorber were studied in order to search alternative materials for thin film solar cell. The films of $Cu_2ZnSnSe_4$ and $Cu_2ZnSnSe_2$ were deposited using mixed binary chalcogenides powders. From the film bulk analysis result, it is observed that Cu concentration is a function of substrate temperature as well as CuSe mole ratio in the target. Under optimized conditions, $Cu_2ZnSnSe_4$ and $Cu_2ZnSnSe_2$ thin films grow with strong (112), (220/204) and (312/116) reflections. Films are found to exhibit a high absorption coefficient of $10^4$ $cm^{-1}$. $Cu_2ZnSnSe_4$ film shows a 1.5 eV band gap. On the other side, an increasing of optical band gap from 1.0 eV to 1.25 eV ($CuInSnSe_2$) is found to be proportional with an increasing of Zn concentration. All films have a p-type semiconductor characteristic with a carrier concentration in the order of $10^{14}$ $cm^{-3}$, a mobility about $10^1$ $cm^{2{\cdot}-1.}S^{-1}$ and a resistivity at the range of $10^2-10^6$ ${\Omega}{\cdot}m$.

• Journal of the Korea Convergence Society
• /
• v.8 no.11
• /
• pp.307-312
• /
• 2017

In the industry, galvanizing using the principle of sacrificial anode is used Zn-Ni alloy plating was developed as one of the measures to increase the corrosion resistance rather than pure zinc plating. The alloy plating layer has a corrosion resistance of 4-5 times that of the pure zinc plating layer, so that it is applied to automotive parts requiring high corrosion resistance even though the plating cost is high. The amount of Zn-Ni alloy plating solution is a sulfuric acid bath, a chlorinated bath, an alkali bath, and an ammonia bath. Here, the influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. The results are explained by the cathode overvoltage and the diffusion coefficient. In general, as the overvoltage of the cathode increases, the concentration polarization becomes more important than the activation polarization. The concentration polarization is determined by element diffusion in the diffusion layer. That is, as the overvoltage of the cathode increases, the Zn content having a large diffusion coefficient increases.

• Journal of the Korean Ceramic Society
• /
• v.41 no.2
• /
• pp.102-105
• /
• 2004

ZnO-In$_2$O$_3$ films were fabricated on Corning 1737 glass substrate by an electron beam evaporation technique and their characteristics were investigated. The composition of ZnO-In$_2$O$_3$ films had a marked effect on the electrical properties of the films. The ZnO-In$_2$O$_3$ films showed superior transparent-conducting characteristics with increase of Zn content. The resistivity and carrier concentration of the film having Zn content of 45 at% are 4.45${\times}$10$^{-3}$ cm and 3.1${\times}$10$^{19}$ cm$^{-3}$ , respectively. Also, the transmittance was higher than 80% throughout the visible range. The average roughness of the film was 14.6 $\AA$ in terms of root mean square.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.12
• /
• pp.1320-1325
• /
• 1998

ZnGa2O4: Mn phosphors were prepared by a new chemical process, and their photoluminescence and electron paramagnetic resonance characteristics were investigated. The chemical method showed a low temperature formation of phosphors and a rod-type shape of particles. The strong ultraviolet emission was observed in the undoped ZnGa2O4 phosphor, while strong green emission in the Mn2+-activated ZnGa2O4 phosphor. The green emission intensity of the phosphor prepared by the chemical method was much stronger than that prepared by the conventional method. This difference with preparation methods was interpreted as due to the difference in the distribution of Mn2+ in the host lattice. From EPR results, it was explained that the line intensity of the undoped ZnGa2O4 is associated with the electrical conductivity of this material and the concentration quenching of green luminescence of ZnGa2O4: Mn at higher Mn2+ concentration is attributed to the coupling by exchange interaction between Mn2+ ions.

• Journal of the Korean Chemical Society
• /
• v.66 no.5
• /
• pp.341-348
• /
• 2022

In this work, radio frequency magnetron sputtering was used to deposit zinc selenide thin films on p-type silicon (100) wafers and glass substrates in a high vacuum chamber. Several surface characterization instruments were implemented to study the thin films. X-ray photoelectron spectroscopy results revealed that oxidized Zn bound to Se (Zn-Se) at 1022.7 ± 0.1 eV becomes the dominant oxidized species when Se concentration exceeds 70%. Scanning electron microscopy coupled with energy dispersive spectroscopy showed that incorporating Se in Zn thin films will lead to formation of ZnSe grains on the surface. Contact angle measurements indicated that ZnSe-60 exhibited the lowest total surface free energy value of 24.94 mN/m. Lastly, ultraviolet-visible spectrophotometry and ultraviolet photoelectron spectroscopy data evinced that the energy band gap gradually increases with increasing Se concentration with ZnSe-70 having the highest work function value of 4.91 eV.

• Journal of the Korean Vacuum Society
• /
• v.18 no.1
• /
• pp.73-78
• /
• 2009

Zinc Oxide (ZnO) nanorods arrays were deposited on ZnO buffered p-Si(100) substrates by hydrothermal method. The ZnO buffer layer with a thickness of 30 nm was deposited by metal oxide chemical vapor deposition at $500^{\circ}C$. The structural and optical properties of ZnO nanorods arrays controlled by precursor concentrations from 0.06 to 0.5 M were studied by FE-SEM(field emission scanning electron microscopy), XRD(X-ray diffraction), and PL(photoluminescence), respectively. It was found that the structural and optical properties of ZnO nanorods arrays are changed significantly with increase of precursor concentration. The sizes of diameter and length of nanorods were increased as the concentration increase, and good optical property was shown with the concentration of 0.3 M.

• Journal of environmental and Sanitary engineering
• /
• v.23 no.1
• /
• pp.33-48
• /
• 2008

The purpose of this study was to characterize background mass concentration of $PM_{10},\;PM_{2.5}$ and metallic composition from June 2004 to June 2005 in comparison with Seoul and Asan city. The results were as follows: 1. Annual mean of $PM_{10}$ concentrations in Seoul and Asan were $56.95({\pm}25.63){\mu}g/m^3,\;57.02({\pm}27.22){\mu}g/m^3$ respectly. 2. Annual mean of $PM_{2.5}$ concentrations in Seoul and Asan were $46.97({\pm}40.36){\mu}g/m^3,\;42.16({\pm}21.79){\mu}g/m^3$ respectly. 3. The average $PM_{2.5}/PM_{10}$ ratio was 0.82 in Seoul and 0.74 in Asan city. 4. The concentration of $PM_{10},\;PM_{2.5}$ were the highest in spring and the lowest in summer. Asan was higher than Seoul in spring and summer. 5. The results showed that average $PM_{10}$ composition order as Si>Fe>Pb>Zn>Mn in Seoul and Si>Fe>Zn>Pb>Mn in Asan. The concentration of metals in $PM_{10}$ of Seoul that Cr, Cu, Fe, Mn were high in spring and Zn was low in Fall. Fe, Mn were high in spring of Asan. 6. The results showed that average $PM_{2.5}$ composition order as Si>Pb>Fe>Zn>Mn in Seoul and Si>Fe>Pb>Zn>Cr in Asan. The concentration of metals in $PM_{2.5}$ of Seoul that Cr was high in spring. 7. The result showed that relation between Cr and Cu, Cu and Fe, Fe and Mn, Mn and Zn, Zn and Si in Seoul, Cr and Zn, Cu and Pb, Zn and Pb, Pb and Mn in Asan. The result showed that $PM_{10}$ concentration exceeding $50{\mu}g/m^3$(US-EPA Standard) and $PM_{2.5}$ concentration exceeding $15{\mu}g/m^3$(US-EPA Standard). In urban area, the monitoring of $PM_{2.5}$ permits the anthropogenic sources and the interference of natural sources with respect to $PM_{10}$ measurements.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.18 no.6
• /
• pp.253-257
• /
• 2008

To enhance the luminescence properties, the red phosphor composed of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ as doping concentration of Zn ion is synthesized at $1200^{\circ}C$ for 6 hrs in air atmosphere by conventional solid reaction method. As a result of the red phosphor $(Y,\;Zn)_2O_3$:$Eu^{3+}$ is measured X-ray diffraction (XRD), The main peak is nearly corresponded to the same as JCPDS card (No. 41-1105). When the doping concentration of Zn ion is more than 5 mol%, However, the ZnO peak is showed by XRD analysis. Therefore, when the doping concentration of Zn ion is less than 5 mol%, the Zn ion is well mixed in $Y_2O_3$ structure without the impurity phases. The photoluminescence (PL) properties is shown as this phosphor is excited in 254 nm region and the highest emission spectra of $(Y,\;Zn)_2O_3$:$Eu^{3+}$ has shown in 612 nm region because of a typical energy transition ($^5D_0{\rightarrow}^7F_2$) of $Eu^{3+}$ ion. As the doping concentration of Zn ion is more than 10 mol%, the emission peak is suddenly decreased. when the highest emission peak as doping concentration of Zn ion is shown, the composition of this phosphor is $(Y_{0.95},\;Zn_{0.05})_2O_3$:$Eu^{3+}_{0.075}$ and the particle size analyzed by FE-SEM is confirmed from 0.4 to $3{\mu}m$.