(Korea Atomic Energy Research Institute)
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(Korea Atomic Energy Research Institute)
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The effects of chemical species in groundwater on the solubility of the uranyl hydrolysis precipitates formed at pH 6.4 and 9.7 were investigated. Based on the chemical composition of the groundwater, the synthetic groundwater was prepared. The colloid-free (separated) groundwater was also prepared by removal of both organic and inorganic colloids from the sampled groundwater. Solubilities of precipitates formed in the hydrolysis of uranyl ion in groundwater, separated groundwater, synthetic groundwater and 0.1 M NaCl solution were measured over neutral to alkaline pH range, and especially, the effect of the anions and cations found in groundwater on the solubility was investigated. Solubility in groundwater was approximately two orders of magnitude greater than that in 0.1 M NaCl solution. Soubililties of uranyl hydrolysis precipitates formed at pH 9.7 and 6.4 were compared in groundwater and synthetic groundwater. Solubilities of the precipitates formed at different pH were found to be in the same order of magnitude in groundwater and synthetic groundwater, however the uranyl hydolysis precipitates formed at higher pH values showed a tendency of higher solubility.
서로 다른 pH 조건에서 생성한 우라닐 가수분해물의 용해도에 미치는 지하수 성분의 영향을 측정하였다. 우라닐 가수분해 침전물 pH 6.4 및 9.7에서 제조하였다. 편마암 층에서 채취한 지하수로부터 무기 및 유기콜로이드를 제거한 분리지하수, 채취지하수의 분석성분과 동일한 조성을 가지는 합성지하수, 그리고 0.1 M NaCl 수용액에서의 용해도에 미치는 pH의 영향을 측정하였다. 또한 채취지하수에서 상대적으로 다량 존재하는 음이온 및 양이온의 영향을 측정하였다. 지하수에서의 우라닐 가수분해 침전물의 용해도는 0.1 M NaCl 용액에서보다 약 100배 정도 큰 것으로 나타났다. X-선 회절분석 결과는 높은 pH에서 제조한 우라닐 가수분해 침전물이 낮은 pH에서 제조한 것보다 낮은 결정화도와 높은 용해도를 보였다.