Removal of 90Sr from highly Na+-rich liquid nuclear waste with a layered vanadosilicate

Abstract

Capture of trace amounts (parts per trillion or ppt level) of ⁹⁰Sr from highly Na⁺-rich (5 M or 115 000 parts per million) liquid wastes produced from reprocessing of spent nuclear fuel rods is crucial for continuous operation of nuclear power plants. However, no sorbents have shown such abilities. We now report that a novel layered vanadosilicate, SGU-7, with the unit cell parameters of a = 23.58 Å, b = 30.04 Å, c = 12.31 Å, β = 100.2°, and space group of P12₁/a1, can effectively capture ⁹⁰Sr from a 5 M Na⁺ solution containing 6.2 ppt of ⁹⁰Sr. It also effectively captures 1-ppb level ²²⁶Ra from 2 M NaCl solution, and Cs⁺ and Sr²⁺ from groundwater, demonstrating that it can be immediately used to remedy groundwater and soil contaminated with ²²⁶Ra, ⁹⁰Sr, and ¹³⁷Cs.