• Title, Summary, Keyword: zeolite-coated

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Photocatalytic removal of NOx using TiO2-coated zeolite

  • Mendoza, Joseph Albert;Lee, Dong Hoon;Kang, Joo-Hyon
    • Environmental Engineering Research
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    • v.21 no.3
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    • pp.291-296
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    • 2016
  • Application of photocatalytic nanoparticles has been recently gaining an increased attention as air purifying material for sustainable urban development. The present work reports the photocatalytic removal of gaseous phase nitrogen oxides ($NO_x$) using $TiO_2$-coated zeolite to be applied as a filter media for the urban green infrastructure such as raingardens. The $TiO_2$-coated zeolite was synthesized by simple wet chemistry method and tested in a continuous-flow photo-reactor for its removal efficiency of $NO_x$ under different conditions of the weight percentage of $TiO_2$ coated on the zeolite, and gas retention time. The removal efficiency of $NO_x$ in general increased as the weight percentage of $TiO_2$ coated on the zeolite increased up to 15-20%. Greater than 90% of $NO_x$ was removed at a retention time of one minute using the $TiO_2$-coated zeolite ($TiO_2$ weight percentage = 20%). Overall, $TiO_2$-coated zeolite showed greater efficiency of $NO_x$ removal compared to $TiO_2$ powder probably by providing additional reaction sites from the porous structure of zeolite. It was presumed that the degradation of $NO_x$ is attributed to both the physical adsorption and photocatalytic oxidation that could simultaneously occur at the catalyst surface.

Properties of Zeolite Nanopowder Coated with Titanium Dioxide by Atomic Layer Deposition

  • Lee, Bo Kyung;Ok, Hae Ryul;Bae, Hye Jin;Kim, Hyug Jong;Choi, Byung Ho
    • Korean Journal of Materials Research
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    • v.26 no.3
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    • pp.149-153
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    • 2016
  • Nanosized zeolites were prepared in an autoclave using tetraethoxysilane (TEOS), tetrapropylammonium hydroxide (TPAOH), and $H_2O$, at various hydrothermal synthesis temperatures. Using transmission electron microscopy and particle size analysis, the nanopowder particulate sizes were revealed to be 10-300 nm. X-ray diffraction analysis confirmed that the synthesized nanopowder was silicalite-1 zeolite. Using atomic layer deposition, the fabricated zeolite nanopowder particles were coated with nanoscale $TiO_2$ films. The $TiO_2$ films were prepared at $300^{\circ}C$ by using $Ti[N(CH_3)_2]_4$ and $H_2O$ as precursor and reactant gas, respectively. In the TEM analysis, the growth rate was ${\sim}0.7{\AA}/cycle$. Zeta potential and sedimentation test results indicated that, owing to the electrostatic repulsion between $TiO_2$-coated layers on the surface of the zeolite nanoparticles, the dispersibility of the coated nanoparticles was higher than that of the uncoated nanoparticles. In addition, the effect of the coated nanoparticles on the photodecomposition was studied for the irradiation time of 240 min; the concentration of methylene blue was found to decrease to 48%.

Anti-Corrosion Performance of the Novel Pigment, Ion-Exchanged Zeolite for the Protection of Galvanized Steel (아연도금강판의 방식을 위한 새로운 방청안료인 이온 교환된 제올라이트의 방청 성능)

  • Kim, Jung-Teag;Jeong, Ho-Su;Ryu, Sang-Su;Lee, Gun-Dae;Park, Jong-Myung
    • Korean Chemical Engineering Research
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    • v.49 no.6
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    • pp.745-751
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    • 2011
  • In this study, zinc or cerium exchanged zeolite was introduced to develop a novel anti-corrosion pigment. The primer paint was made using them and was coated on galvanized(GI) steel. The anti-corrosion performance was measured using electrochemical impedance spectroscopy(EIS). And scanning vibrating electrode technique(SVET) was employed to observe the cut-edge corrosion process of the coated GI steel. From EIS and SVET results, it could be confirmed that Ce ion-exchanged zeolite showed the anti-corrosion performance higher than Shieldex C303 and Zn ionexchanged zeolite. Finally, it was found that metal ion-exchanged zeolite may provide new possibility as the smart cathodic corrosion inhibitor delivery systems on galvanized steels.

Immobilization of oxidative enzymes onto Cu-activated zeolite to catalyze 4-chlorophenol decomposition

  • Zol, Muhamad Najmi Bin;Shuhaimi, Muhammad Firdaus Bin;Yu, Jimin;Lim, Yejee;Choe, Jae Wan;Bae, Sungjun;Kim, Han S.
    • Membrane Water Treatment
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    • v.11 no.3
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    • pp.195-200
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    • 2020
  • In this study, a biocatalyst composite was prepared by immobilizing oxidoreductases onto Cu-activated zeolite to facilitate biochemical decomposition of 4-chlorophenol (4-CP). 4-CP monooxygenase (CphC-I) was cloned from a 4-CP degrading bacterium, Pseudarthrobacter chlorophenolicus A6, and then overexpressed and purified. Type X zeolite was synthesized from non-magnetic coal fly ash using acetic acid treatment, and its surfaces were coated with copper ions via impregnation (Cu-zeolite). Then, the recombinant oxidative and reductive enzymes were immobilized onto Cu-zeolite. The enzymes were effectively immobilized onto the Cu-zeolite (79% of immobilization yield). The retained catalytic activity of CphC-I after immobilization was 0.3423 U/g-Cu-zeolite, which was 63.3% of the value of free enzymes. The results of this study suggest that copper can be used as an effective enzyme immobilization binder because it provides favorable metalhistidine binding between the enzyme and Cu-zeolite.

Preparation of Zeolite Coated with Metal-Ferrite and Adsorption Characteristics of Cu(II) (금속 페라이트가 코팅된 제올라이트의 제조와 Cu(II)의 흡착 특성)

  • Baek, Sae-Yane;Nguyen, Van-Hiep;Kim, Young-Ho
    • Applied Chemistry for Engineering
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    • v.30 no.1
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    • pp.54-61
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    • 2019
  • In this study, a magnetic adsorbent was synthesized by growing ferrite nanoparticles substituted with metals (Me = Co, Mn, Ni) on zeolite 4A for the efficient separation of waste adsorbents present in the solution after the adsorption of Cu(II). The metal ferrite grown on the surface of zeolite was prepared by solvothermal synthesis. Characteristics of the magnetic adsorbent were analyzed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and physical property measurement system (PPMS). The saturation magnetization of the A type zeolite coated with Co-ferrite (CFZC) was the highest at 5 emu/g and the Cu(II) adsorption performance was also excellent. The adsorption results of Cu(II) on CFZC were well fitted by the Langmuir model at 298 K. Also, the adsorption of Cu(II) on CFZC follows a pseudo-second order kinetic. The Gibbs free energy values (${\Delta}G^0$) ranging from -4.63 to -5.21 kJ/mol indicates that the Cu(II) adsorption is spontaneous in the temeprature range between 298 and 313 K.

Preparation of Oriented MFI Zeolite Membranes (배향된 MFI 제올라이트 박막의 제조)

  • Song, Kyeong-Keun;Ha, Kwang
    • Korean Chemical Engineering Research
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    • v.44 no.3
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    • pp.243-247
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    • 2006
  • MFI zeolite membranes were prepared on anodic alumina (Anodisc) as support. First, silicalite-1(${\approx}1.2{\mu}m$) seed crystals were attached to the surface of the support via chemical bonding, and the a- and b-axis oriented zeolite membranes could be synthesized on the support coated with the monolayer of the seed crystals by secondary growth hydrothermal synthesis. The zeolite membranes prepared were characterized using scanning electron microscope and analyzed by X-ray diffraction.

Preparation of Zeolite Membranes on Papers or Fibers (종이나 섬유를 지지체로 이용한 제올라이트 박막의 제조)

  • Song, Kyeong-Keun;Ha, Kwang
    • Korean Chemical Engineering Research
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    • v.43 no.6
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    • pp.691-695
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    • 2005
  • Zeolite membranes on various supports such as filter paper, cotton fiber, and glass fiber filter were prepared by secondary growth hydrothermal synthesis. First, zeolite NaA (${\approx}0.5{\mu}m$) and silicalite-1 (${\approx}0.2{\mu}m$) crystals were synthesized as zeolite seed crystals, and they were attached to the surfaces of the supports via chemical bonding. Zeolite NaA or silicalite-1 membranes could be synthesized on the supports coated with the seed crystals. The prepared zeolite membranes were observed by scanning electron microscope and analyzed by X-ray diffraction.

Effects of Coating Materials on Germination of Pelleted Tobacco (Nicotiana tabacum L.) Seeds (피복재료가 품종별 연초 피복종자의 발아에 미치는 영향)

  • 민태기;이윤환
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.28 no.1
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    • pp.139-143
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    • 1983
  • Nicotiana Tabacum L., cv. NC2326, Burley2l and Sohyang seeds were coated with different five materials - zeolite, serpentine, coal briquet ash, serpentine+zeolite and coal briquet ash+zeolite - to investigate the effects of coating on germination. The coating materials had different characteristics and gave varied effects on germination. Among three tobacco varieties, coated seeds of Burley2l showed the most sensitive responses in germination rate of decreasing and delaying at low temperature on seedbed and laboratory tests.

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Coating Method and Germination Test of Coated Tobacco (Nicotiana tabacum L.) Seeds (담배종자의 피복대형화방법과 발아에 미치는 영향)

  • 이윤환;민태기;강정용
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.28 no.1
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    • pp.144-149
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    • 1983
  • Experiments were conducted to develop a pelletization method of minute tobacco seeds for easy handling at seeding by hand or for mechanical seeding. Serpentine, zeolite, and talc were tested as coating materials and the resulting pills were compared in size uniformity, hardness, length of time needed for coating, percentage of pills containing a single seed, and speed of disintegration when submerged in water. Talc was the poorest and zeolite was good only in hardness. On the other hand serpentine was good in most characters above, except for brittleness. This defect, however, was overcome by double coating, first with serpentine and followed by zeolite. This new pelletizing method results in optimum hardness, uniform size, and high ratio of pellets containing one tobacco seed. When compared to bare tobacco seeds, the double-coated seeds did not differ in germination test.

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Effects of Y-Zeolite as a Support on CO, $CC_3H_6$ Oxidation for Diesel Emission Control (디젤엔진 배출가스 저감을 위한 CO, $C_3H_6$의 산화반응에서 Y-제올라이트 담체의 영향)

  • 김문찬
    • Journal of Korean Society for Atmospheric Environment
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    • v.13 no.1
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    • pp.91-98
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    • 1997
  • Y-zeolite and ${\gamma}$-Al$_2$O$_3$ were used as supports on CO and $C_3$H$_{6}$ oxidation for diesel emission control. The catalysts composed of Pd and Pt as active components were wash coated on honeycomb type ceramic substrate. The oxidation of CO and $C_3$H$_{6}$ was carried out over prepared honeycomb in a fixed bed continuous reactor in the temperature range of 20$0^{\circ}C$~50$0^{\circ}C$ and 20,000 GHSV (h$^{-1}$ ). Surface area of Y-zeolite was larger than that of ${\gamma}$-Al$_2$O$_3$ due to channel structure of Y-zeolite. Therefore, high conversion of CO and $C_3$H$_{6}$ could be obtained because of good dispersion of active metals over Y-zeolite. The honeycomb used Y-zeolite as a support showed higher $C_3$H$_{6}$ conversion than that of ${\gamma}$-Al$_2$O$_3$ due to better cracking and isomerization activity of Y-zeolite. PdPt catalyst showed high conversion of CO and $C_3$H$_{6}$ at low temperature region, 20$0^{\circ}C$~30$0^{\circ}C$, for their synergy effects. PdPt/Y-Zeolite catalyst could achieve more than 80% conversion of $C_3$H$_{6}$ at 30$0^{\circ}C$. The use of Y-zeolite as a support increased CO and $C_3$H$_{6}$ conversion, and decreased SO$_2$ conversion very effectively. Y-zeolite found to have a good adaptability as a support for the diesel emission after treatment system.

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