Journal of Soil and Groundwater Environment (한국지하수토양환경학회지:지하수토양환경)

Korean Society of Soil and Groundwater Environment (한국지하수토양환경학회)
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A Study on the Stability of the Ca-Bentonite Colloids Using a Dynamic Light Scattering Method

동적광산란 방법을 이용한 칼슘벤토나이트 콜로이드의 안정성에 대한 연구

  • Published : 2006.06.01
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Abstract

In this study, the stability of Ca-bentonite colloids from Gyeongju area was studied by investigating the changes in the size of the bentonite colloids using a dynamic light scattering method depending on the geochemical conditions such as pH and ionic strength. Kinetic and equilibrium coagulation behavior of the bentonite colloids was investigated by changing the pH and ionic strength of the bentonite suspensions. The results showed that the stability of the bentonite colloids strongly depended upon contact time, pH, and ionic strength. It was also shown that the bentonite colloids were unstable at higher ionic strength greater than 0.01 M $NaClO_4$ at whole pH values considered. In addition, the stability ratio Wand the critical coagulation concentration (CCC) were also calculated using the data from the kinetic coagulation experiments. The stability ratio W was decreased as the ionic strength increased and varied with pH depending on the ionic strength. The CCC of the Ca-bentonite colloids was about 0.05 M $NaClO_4$ around pH 7.

본 연구에서는 우리나라의 경주에서 산출된 칼슘벤토나이트 콜로이드의 안정성에 대한 연구를 동적광산란 방법을 이 용하여 이온강도 및 pH 등의 지화학적 조건 변화에 따른 크기 변화를 관측함으로써 수행하였다. 속도론적 및 평형상태에서 pH 및 이온강도의 변화에 따른 칼슘벤토나이트 콜로이드의 크기변화를 관측하였다. 실험결과 칼슘벤토나이트 콜로이드의 안정성은 접촉시간, 매질의 이온강도와 pH 에 매우 크게 의존함을 보였으며 0.01 M $NaClO_4$ 이상의 이온강도에서는 고려된 대부분의 pH 에서 콜로이드가 불안정함을 보였다. 아울러 칼슘벤토나이트 콜로이드의 안정비 W와 CCC(Critical Coagulation Concentration) 등을 속도론적 응집 실험 자료들을 이용하여 계산하였다. 안정비 W는 이온강도가 증가함에 따라 감소하는 경향을 뚜렷하게 나타내었으며 pH 변화에 따른 W 값의 변화는 이온강도에 따라 다른 양상을 보였다. 또 pH 7 근처에서 칼슘벤토나이트 콜로이드의 CCC 는 약 0.05 M $NaClO_4$ 임을 알 수 있었다.

Keywords

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