• Title/Summary/Keyword: NaOH/ZnO solution

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Fabrication of ZnO incorporated TMA-A zeolite nanocrystals (ZnO를 담지한 TMA-A 제올라이트 나노결정의 제조)

  • Lee, Seok-Ju;Lim, Chang-Sung;Kim, Ik-Jin
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.17 no.6
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    • pp.238-244
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    • 2007
  • Nano-sized ZnO crystals were successfully incorporated using ion exchange method in TMA-A zeolite synthesized by the hydrothermal method. The optimal composition for the synthesis of TMA-A zeolite was resulted in a solution of $Al(i-pro)_3$:2.2 TEOS:2.4 TMAOH:0.3 NaOH:200 $H_2O$. 0.3g of TMA-A zeolite and 5mol of $ZnCl_2$ solution were employed for the preparation of ZnO incorporated TMA-A zeolite. The ZnO incorporated TMA-A zeolite precursors, prepared from the process of mixing, stirring, centrifugal separation and drying, were calcined at temperatures from 400 to $600^{\circ}C$ for 3 h. The crystallization process of ZnO incorporated TMA-A zeolite was analyzed by X-ray diffraction (XRD). The Brunaur-Emett-Teller (BET) surface area of the ZnO incorporated TMA-A zeolite was measured. Subsequently, the morphology and the particle size depending on the temperature and time were observed using scanning electron microscopy(SEM), transmission electron microscopy(TEM) and particle size analyzer.

Synthesis of zinc oxide nanoparticles via aqueous solution routes (수용액 합성법에 의한 ZnO 나노분말의 합성)

  • Koo, Jin Heui;Yang, Jun Seok;Cho, Soo Jin;Lee, Byeong Woo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.5
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    • pp.175-180
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    • 2016
  • ZnO nanoparticles were synthesized by aqueous preparation routes of a precipitation and a hydrothermal process. In the processes, the powders were formed by mixing aqueous solutions of Zn-nitrate hexahydrate ($Zn(NO_3)_2{\cdot}6H_2O$) with NaOH aqueous solution under controlled reaction conditions such as Zn precursor concentration, reaction pH and temperature. Single ZnO phase has been obtained under low Zn precursor concentration, high reaction pH and high temperature. The synthesized particles exhibited flakes (plates), multipods or rods morphologies and the crystallite sizes and shapes would be efficiently controllable by changing the processing parameters. The hydrothermal method showed advantageous features over the precipitation process, allowing the precipitates of single ZnO phase with higher crystallinity at relatively low temperatures below $100^{\circ}C$ under a wider pH range for the Zn precursor concentration of 0.1~1 M.

Ionic Equilibria in $ZnSO_4-Na_2SO_4-H_2SO_4-NaOH-H_2O$ System ($ZnSO_4-Na_2SO_4-H_2SO_4-NaOH-H_2O$계의 이온 평형)

  • 이만승;박현주;나춘기
    • Resources Recycling
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    • v.11 no.1
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    • pp.19-25
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    • 2002
  • For $ZnSO_4$-$Na_2$$SO_4$-$H_2$ $SO_4$-$NaOH-H_2$O system, pH of solutions with different electrolyte concentrations was measured at $25^{\circ}C$ and ionic equilibria were analyzed by using K-value method. Activity of water and activity coefficients of solutes were calculated by Pitzer equation. The equilibrium concentration and activity coefficients of solutes were calculated from initial experimental conditions. At high ionic strength of 4m, the pH values calculated were in good agreement with those measured. In the experimental ranges of ionic strength of solution from 3.5 to 4.3 m, the mean activity coefcient of $ZnSO_4$calculated agreed well with those obtained from literature.

Preparation of ZnO nanorods by hydrothermal method and their $NO_2$ sensing characteristics (수열합성법을 이용한 ZnO 나노로드의 제조 및 이산화질소 감응 특성)

  • Cho, Pyeong-Seok;Kim, Ki-Won;Lee, Jong-Heun
    • Journal of the Korean Vacuum Society
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    • v.15 no.5
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    • pp.506-511
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    • 2006
  • ZnO nanorods were prepared by the hydrothermal reaction of a solution containing $Zn(NO_3)_2{\cdot}6H_2O$, NaOH, cyclohexylamine, ethanol and water, and their $NO_2$ and CO sensing behaviors were investigated. By the control of water concentration in solution, the morphology and agglomeration of ZnO nanorods could be manipulated, which is associated with the variation of $[OH^-]$ resulted from an interaction between water and cyclohexylamine. Sea-urchin-like and well-dispersed ZnO nanorods were prepared at low and high water content, respectively. Well-dispersed ZnO nanorods showed 1.8 fold change in resistance at 1 ppm $NO_2$ while there was no significant change in resistance at 50 ppm CO. This selective detection of $NO_2$ in the presence of CO can be used in automated car ventilation systems.

A study on the zinc oxide crystalline powder synthesized by zinc chloride solution and sodium-based alkali precipitants (염화아연 수용액과 나트륨계 알칼리 침전제 종류에 따라 합성한 산화아연 결정 분말에 대한 연구)

  • Dae-Weon Kim;Dae-Hwan Jang;Bo-Ram Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.1
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    • pp.15-21
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    • 2023
  • To prepare zinc oxide powder, three types of sodium-based alkali precipitants such as NaOH, Na2CO3, NaOH/NaHCO3 were compared to the differences in the manufacturing process of zinc oxide powder from zinc precipitate products like intermediates with the consideration of thermodynamic reaction. The prepared zinc precipitate products by the reaction with the sodium-based alkali precipitant were confirmed to respectively hydroxy zinc chloride (Zn5(OH)8Cl2·H2O) and zinc carbonate hydroxide (Zn5(OH)6(CO3)2·H2O) from XRD analysis. Zinc oxide particles were compared in heat treatment at 800℃ according to sodium-based alkali precipitants. The mixed NaOH and NaHCO3 of alkali precipitant reaction was contributed to synthesize the more uniform zinc oxide particles.

Apoptosis and inhibition of human epithelial cancer cells by ZnO nanoparticles synthesized using plant extract

  • Koutu, Vaibhav;Rajawat, Shweta;Shastri, Lokesh;Malik, M.M.
    • Advances in nano research
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    • v.7 no.4
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    • pp.233-240
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    • 2019
  • The present research work reports in-vitro anti-cancer activity of biologically synthesized ZnO nanoparticles (ZnO NPs) against human carcinoma cells viz SCC-40, SK-MEL-2 and SCC-29B using Sulforhodamine-B (SRB) Assay. ZnO NPs were synthesized by a unique and novel biological route using Temperature-gradient phenomenon where the extract of combination of Catharanthus roseus (L.) G. Don (C. roseus), Azadirachta indica (A. indica), Ficus religiosa (F. religiosa) and NaOH solution were used as synthesis medium. The morphology of the ZnO NPs was characterized by Transmission Electron Microscopy (TEM). TEM images reveal that particle size of the samples reduces from 76 nm to 53 nm with the increase in reaction temperature and 68 nm to 38 nm with the increase in molar concentration of NaOH respectively. XRD study confirms the presence of elements and reduction in crystallite size with increase in reaction temperature and NaOH concentration. The diffraction peaks show broadening and a slight shift towards lower Bragg angle ($2{\theta}$) which represents the reduction in crystallite size as well as presence of uniform strain. The FTIR spectra of the extract show transmittance peak fingerprint of Zn-O bond and presence of bioactive molecules These NPs exhibit inhibition greater than 50% for SCC-40, SK-MEL-2 and SCC-29B cell lines and more than 50% cell kill for SCC-29B cells at concentrations < $80{\mu}g/ml$. Nanoparticles with smallest size have shown better anti-cancer activity and peculiar cell-selectivity. The combination of extracts of these plants with ZnO NPs can be used in targeted drug delivery as an effective anti-cancer agent, a potential application in cancer treatment.

Studies on Hexagonal Ferrite (III) Coprecipitation-Method Preparation of Ferroxplana ZnY $(Ba_2Zn_2Fe_{12}O_{22})$ and Its magnetic Properties (Hexagonal Ferrite에 관한 연구 (III) 공침법에 의한 Ferroxplana ZnY $(Ba_2Zn_2Fe_{12}O_{22})$의 합성과 그 자성)

  • 김태옥;신학기
    • Journal of the Korean Ceramic Society
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    • v.16 no.2
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    • pp.89-98
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    • 1979
  • In order to prepare ferroxplana ZnY $(Ba_2Zn_2Fe_{12}O_{22})$, which would be useful for GHz-band communication, the optimum coprecipitation condition of 1 $BaCl_{2-1} Zn(NO_3)_2-6FeCl_3$ in $NaOH-Na_2CO_3$ solution was investigated by use of a new apparatus invented in our laboratory. By freeze-drying and calcining the coprecitated hydroxide-carbonate, the very reactive powder was obtained, from which the synthesis process of ZnY and the other related crystals were investigated by means of X-ray diffraction. In results, it was found that the reactive powder containing ZnY as the major component can be prepared by this method, which may be used in manufacturing the various magnetic cores for the microwave communication.

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Preparation of Regenerated Cellulose Fiber via Carbonation (II) - Spinning and Characterization -

  • Oh Sang Youn;Yoo Dong Il;Shin Younsook;Kim Hak Yong;Kim Hwan Chul;Chung Yong Sik;Park Won Ho;Youk Ji Ho
    • Fibers and Polymers
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    • v.6 no.2
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    • pp.95-102
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    • 2005
  • Sodium cellulose carbonate (CC-Na) dissolved in $8.5\;wt\%$ NaOH/ZnO (100/2-3, w/w) aqueous solution was spun into some acidic coagulant systems. Diameter of regenerated cellulose fibers obtained was in the range of $15-50\;{\mu}m$. Serrated or circular cross sectional views were obtained by controlling salt concentration or acidity in the acid/salt/water coagulant systems. Velocity ratio of take-up to spinning was controlled up to 4/1 with increasing spinning velocity from 5 to 40 m/min. Skin structure of was developed at lower acidity or higher concentration of coagulants. Fineness, tenacity and elongation of the regenerated cellulose fibers were in the range of 1.5-27 denier, 1.2-2.2 g/d, and $8-11.3\;\%$, respectively. All of CC-Na and cellulose fibers spun from CC-Na exhibited cellulose II crystalline structure. Crystallinity index was increased with increasing take-up speed.

Fabrication of dye sensitized solar cell by multiple growth of ZnO particle (ZnO 입자 다중 성장을 이용한 염료 감응형 태양 전지 제작)

  • Choi, Jin-Ho;Son, Min-Kyu;Kim, Jin-Kyoung;Choi, Seok-Won;Prabakar, K.;Kim, Hee-Je
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1469-1470
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    • 2011
  • 본 연구에서는 ZnO 입자 다중 성장을 이용하여 DSC를 제작하여 ZnO DSC의 가능성을 점검하고자 하였다. ZnO 입자 성장은 zinc acetate solution을 이용하여 seed layer를 제작한 후 zinc nitrate와 NaOH 혼합 용액에 다중성장 시킴으로써 완성되며 이를 이용하여 ZnO DSC를 제작하였다. 그 결과 ZnO가 입자형태로 얻어짐을 확인하고 ZnO DSC를 성공적으로 제작할 수 있었으며 ZnO 입자 성장 후 소성을 통해 ZnO DSC의 성능을 0.406%에서 1.385%까지 개선시킬 수 있었다.

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Comparison of Ionic Equilibria Analysis of ZnSO4-Fe2(SO4)3-Na2SO4-H2SO4-NaOH-H2O System at 25℃ between Pitzer and Vasil'ev Equation (25℃에서 ZnSO4-Fe2(SO4)3-Na2SO4-H2SO4-NaOH-H2O계에 대해 Pitzer식과 Vasil'ev식에 의한 이온평형해석 비교)

  • Lee, Man-Seung;Lee, Kyoung-Ju;Nam, Sang-Ho
    • Analytical Science and Technology
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    • v.16 no.2
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    • pp.159-165
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    • 2003
  • To develop an ionic equilibria model applicable to the sulfuric acid leaching solutions of zinc oxide ore, the method of the Pitzer equation and that of the Vasil'ev equation were compared. As the ionic strength of the solution increased to 9 m, the results of ionic equilibria by the Pitzer equation were more accurate than those by Vasil'ev. To simulate the sulfuric acid leaching solutions of zinc oxide ore, the mixed solutions with the various composition of $ZnSO_4-Fe_2(SO_4)_3-Na_2SO_4-H_2SO_4-NaOH-H_2O$ were prepared. The pH values calculated in this study agreed well with those measured at $25^{\circ}C$.