A Study on the Adsorption Characteristic of Cobalt on ZrO2 in High-Temperature Water

고온수중에서 ZrO2의 코발트흡착 특성에 대한 연구

  • Received : 1995.11.10
  • Accepted : 1997.02.24
  • Published : 1997.04.10

Abstract

$ZrO_2$ Powder was Prepared by sol-gel process and the adsorption characteristic of cobalt($Co^{2+}$) by $ZrO_2$ adsorbent in high-temperature water was investigated using batch adsorption experiment with a stirred autoclave. The prepared $ZrO_2$ was calcined at $600{\sim}1400^{\circ}C$ and analyzed by X-ray diffractometry, SEM, BET surface area, FT-IR and TG-DTA measurement. The tetragonal Phase of $ZrO_2$ is produced $480^{\circ}C$ from amorphous gel at temperature $480^{\circ}C$. Both tetragonal and monoclinic phase of $ZrO_2$ exist at temperature between $600^{\circ}C$ and $1000^{\circ}C$. At temperature $1200^{\circ}C$, tetragonal to monoclinic phase trasition is occurred. The $Co^{2+}$ adsorption capacity of $ZrO_2$ calcined at $600^{\circ}C$ for 4 hours is 0.16 meq $Co^{2+}/g$ adsorbent in the high temperature at $250^{\circ}C$. The adsorption of $Co^{2+}$ on the $ZrO_2$ adsorbent is irreversible endothermic in the temperature range ($125-175^{\circ}C$). The standard enthalpy change (${\Delta}H^{\circ}$) of $ZrO_2$ calcined at $600^{\circ}C$ for 4 hours is 18 kJ/gmol.

본 연구는 졸-겔법을 이용하여 제조한 $ZrO_2$의 하소 온도에 따른 분말특성을 조사하고, 고온수에서 $ZrO_2$$Co^{2+}$ 흡착특성을 교반기가 달린 압력용기를 이용한 회분식 흡착 실험으로 알아보았다. 졸-겔법을 이용하여 $ZrO_2$분말을 제조하고, $600{\sim}1400^{\circ}C$로 하소한 후, X-선 회절법, SEM, BET 방법, Fourier transform 적외선 (FT-IR), 열중량 및 열시차분석법(TG-DTA)등을 이용하여 특성 변화를 조사하였다. 비정질의 질코니아는 $480^{\circ}C$부터 tetragonal 질코니아가 생성되고 $600{\sim}1000^{\circ}C$ 온도범위에서는 tetragonal 질코니아와 monoclinic 질코니아가 공존하며, $1200^{\circ}C$에서는 tetragonal 질코니아에서 monoclinic 질코니아로의 상변태가 나타났으며, 고온수에서 하소온도가 $600^{\circ}C$$ZrO_2$의 흡착제의 코발트 평형흡착용량은 0.16 meq/g 이었다. $125^{\circ}C$ 이상의 고온에서의 흡착반응은 비가역 흡열반응이며, $600^{\circ}C$에서 하소한 $ZrO_2$의 표준엔탈피 변화값(${\Delta}H^{\circ}$)은 약 18 kJ/gmol 이였다.

Keywords

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