Development of isotopic water molecules separation system using thermophoresis effect

Tritium is a radioactive substance contained in contaminated water produced by nuclear power plants. A radioactive substance removal method using the Advanced Liquid Processing System (ALPS) has been used for a contaminated water treatment. However, there is no established technique for removing tritium because it has quite similar chemical properties to hydrogen. To overcome this issue, we proposed a liquid component separation system based on thermophoresis effect for isotopic water molecules separation. The thermophoresis effect generates concentration gradient by temperature gradient. The microfluidic device has a temperature controlled part for generating concentration gradient and a branch part for collecting liquid of each flow layer. The material of the device was decided by a heat transfer simulation using the finite element method. We performed a methyl-beta-cyclodextrin separation experiment to evaluate the function of the device. As a result, we confirmed that the device has a separation ability of different molecular size components by the thermophoresis effect in the microchannel. (author)