유해물질인 요오드 음이온에 대한 흡착특성이 높은 물질을 찾기 위해 여러 종류의 광물과 산화물에 대해 흡착실험을 회분식으로 실시하고 이들의 흡착특성을 비교해 보았다. 문헌조사와 예비 흡착실험결과로부터 황철석, 마그네슘 산화물과 소성된 Mg/Al Layered Double Hydrowide가 요오드 음이온에 대해 비교적 좋은 흡착특성을 나타냄을 알 수 있다. 황철석과 마그네슘 산화물의 경우 흡착제의 농도가 일정할 때 초기 요오드 농도가 증가함에 따라 흡착된 요오드의 농도는 증가하였다. 그리고 이들 물질에 대한 요오드 음이온의 흡착특성은 Freundilch 흡착등온선 형태를 따름을 알 수 있다. 소성된 Mg/Al LDH의 경우는 이산화탄소가 배제된 조건에서 흡착실험을 진행시켰는데 황철석과 마그네슘 산화물에 비해 흡착량이 큼을 알 수 있었다. 그리고 소성된 LDH에 대한 요오드 음이온의 흡착등온선은 Langmuir 형태를 나타내고 이때 얻어진 최대흡착량은 3.8 x 10(-3) mol/g 이며 K(ads)는 7.1 x 10(3)이다. 소성된 LDH에 대한 요오드 음이온의 흡착은 소성된 LDH의 재구성 반응에 의한 것이며 이는 2단계의 이온교환 과정을 포함한다. 수용액중에 존재하는 탄산이온이 요오드 음이온의 흡착에 미치는 영향을 황철석, 마그네슘 산화물과 Mg/Al LDH에 대해 확인해 보면 황철석과 마그네슘 산화물에 요오드 음이온이 흡찰될 때는 탄산이온의 방해를 받지 않고 소성된 LDH의 경우는 탄산이온의 농도가 높을 때 요오드 음이온의 흡착퍼센트가 크게 감소됨을 알 수 있다.

To find out the materials having a high adsorption capacity for iodide anion, the adsorption characteristics of iodide on minerals, rock and oxide compounds were investigated and compared by batch experiments. Pyrite, magnesium oxide and calcined Mg/Al LDH are found as good adsorbents for iodide from literature survey and preliminary experiments. When the amount of pyrite or magnesium oxide was constant, the adsorbed amount was increased with initial iodide concen-tration. The adsorption characteristics of iodide on pyrite or magnesium oxide is represented by Freundlich adsorption iso-therm. The adsorption experiments on calcined Mg/Al LDH were performed under the conditions excluding carbon dioxide. The adsorbed amount of iodide on the calcined LDH was higher than that on pyrite or magnesium oxide. The adsorption char-acteristics of iodide on the calcined LDH is described by Langmuir adsorption isotherm. The maximum adsorbed amount of iodide on the calcined LDH and K(ads) of adsorption reaction, resulted from adsorption isotherm, are 3.8 x 10(-3) mol/g and 7.1 x 10(3), respectively. The adsorption of iodide on the calcined LDH is caused by the reconstruction reaction of the calcined_x000D_ LDH and this reaction includes a two-step ion-exchange process. The influence of carbonate anions of the aqueous solution in the adsorption of iodide on pyrite, magnesium oxide and calcined Mg/Al LDH was also investigated. The adsorbed percent of iodide on pyrite or magnesium oxide in the presence of HCO3(-) is similar to that in the absence of HCO3(-) . However, the adsorbed percent of iodide on the calcined LDH decreased sharply with the concentration of HCO(-).

Iodide Pyrite Magnesium Oxide Mg/Al LDH Adsorption

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