Abstract

The behavior of uranium and thorium ions in nanofiltration (NF) from aqueous solutions has been studied. It was shown that the retention capacity (R) of the NF membrane for uranium and thorium depends on their state in aqueous solutions. In the case of uranium, the smallest values of R (82–83%) are observed when uranium is in solution as uranyl ions or oxyhydrate complexes at pH in the range from 2 to 6. In solutions with large pH values, the retention of uranium increases (R ≈ 95%) due to the formation of an insoluble U(IV) hydroxide and/or carbonate complexes. In the NF of aqueous solutions of thorium, R grows from 94 to 99% with pH increasing from 1 to 3.5, which is due to the hydrolysis of thorium ions to give oxyhydrate complexes of various compositions. At pH 3–9, the retention of thorium remains constant due to the formation of an insoluble thorium hydroxide. In alkaline solutions (pH > 9), values of R decrease because of the formation of negatively charged hydroxo and/or carbonate complexes. A conclusion is made that the nanofiltration is an effective method for wastewater purification to remove admixtures of uranium and thorium.

中文翻译：

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水溶液中铀和Thor的纳滤萃取

摘要

研究了铀和or离子在水溶液中的纳滤（NF）中的行为。结果表明，NF膜对铀和th的保留能力（R）取决于它们在水溶液中的状态。就铀而言，当铀以2至6的pH值存在于铀中时，铀酰离子或羟基氧化物络合物的R值最小（82–83％）。铀的增加（[R ≈95％），由于不溶性U（IV）的氢氧化物和/或碳酸盐复合物的形成。在or水溶液的NF中，RpH值从1升高到3.5时，可从94％增长到99％，这是由于or离子的水解产生了各种组成的羟基复合物。在pH 3–9下，由于不溶性氢氧化hydroxide的形成，th的保留保持恒定。在碱性溶液（pH> 9）中，由于形成带负电荷的羟基和/或碳酸盐复合物，R值降低。结论是，纳滤是一种用于废水净化的有效方法，可去除铀和remove的混合物。