Migration behavior, speciation, and decontamination mechanisms of uranium dust on concrete surfaces using cellulose/PVA strippable coatings

To address the persistent challenge of uranium dust contamination on building surfaces – which is difficult to remove and prone to secondary migration during conventional decontamination – this study developed a cellulose/polyvinyl alcohol (PVA/CMC) composite strippable coating. The decontamination efficiency for uranium dust and its post-decontamination remobilization behavior were systematically investigated. Experiments employed simulated uranium contamination (0.015–0.12 mg per 0.01 m 2 ) and aging periods (15–60 days), combined with sequential chemical extraction, to elucidate the relationship between uranium speciation and its migration response within concrete. The PVA/CMC coating was characterized using FT-IR, contact angle measurements, and mechanical testing to evaluate its decontamination performance and ability to inhibit secondary migration. Results indicate that uranium within concrete primarily existed in reducible (25.5 %) and residual (55.2 %) fractions, with its migration capacity increasing over contamination time. However, due to limited particle diffusion, deep-layer migration rates remained below 2 %. The fabricated PVA/CMC coating achieved a decontamination efficiency of 84.43 % and significantly inhibited uranium remobilization. This inhibition is attributed to dual mechanisms: physical barrier formation and chemical chelation, maintaining a remobilization rate of approximately 15 % post-decontamination (15 days). FT-IR and SEM-EDS analyses revealed that CMC and PVA chains physically entrapped dust particles while carboxyl and hydroxyl groups chemically immobilized uranium. A contact angle of 62° confirmed effective resistance to fluid penetration. This study demonstrates that the PVA/CMC composite coating enables simultaneous high-efficiency removal of uranium and suppression of its migration depth. It provides an innovative solution for the management of concrete surfaces contaminated by uranium dust.