The Separation of Radionuclides and Silicon from Boron-containing Radioactive Wastewater with Modified Reverse Osmosis Membranes

Abstract The ability to reuse boron and minimize the volume of radioactive waste could be accomplished with modified reverse osmosis (RO) membranes. RO membranes were fabricated via polyethylenimine (PEI) grafting to separate silicon and radionuclides from boron-containing radioactive wastewater. The positively charged RO membrane promoted more efficient removal of nuclides and silicon while the rejection of boron declined from 55.88% to 41.71% after modification. Compared with virgin RO membrane, the SFB-Si, SFB-Cs, and SFB-Co of the modified RO membranes increased from 6.02, 5.16, and 12.62 to 29.52, 61.91, and 547.15, respectively. SFB-Si, SFB-Cs, and SFB-Co of the simulated RO system with modified RO membranes further increased to 156.96, 1068.12, and 83617.88, respectively. As a result, permeate water with 433.92 mg L-1 boron, 0.04 mg L-1 silicon, 1.62 μg·L−1 Cs(I), and 0.02 μg·L−1 Co(II) was obtained, which could satisfy radionuclide treatment requirements and allow for the reuse of boron. Overall, modified RO membranes would be able to reuse boron and minimize the volume of discharge of radioactive wastewater.