Hydrothermal synthesis of pollucite with soil and incineration ash for Cs immobilization and its immobilizing mechanism and leaching property

A hydrothermal method has been developed to convert Cs-polluted soil (kaolin) mixed with incineration ashes of plants (rice husk ash) into pollucite for the in situ immobilization of Cs. With the addition of slaked lime, a very tough tobermorite–pollucite body could further be obtained. According to extended X-ray absorption fine structure analysis, Cs did be embedded into the crystal structure of pollucite, which resulted in a perfect Cs leaching performance of the synthesized specimens. As such, the technology has a high potential to be directly applied to the in situ treatment of huge amounts of Cs-polluted soil and incineration ashes of plants. Graphical abstract