Accumulation of U(VI) on the Pantoea sp. TW18 isolated from radionuclide-contaminated soils

Highlights: • Radionuclides-tolerant Pantoea sp. TW18 was isolated from radionuclide-contaminated soils. • Maximum accumulation capacity of U(VI) on Pantoea sp. TW18 was 76.98 mg/g at pH 4.1. • Amino, phosphoryl and oxygen groups on Pantoea sp. TW18 facilitated U(VI) sorption. • Bioaccumulation and surface complexation were the main removal mechanism. -- Abstract: Pantoea sp. TW18 isolated from radionuclide-contaminated soils was used for the bioremediation of radionuclides pollution. Accumulation mechanism of U(VI) on Pantoea sp. TW18 was investigated by batch experiments and characterization techniques. The batch experiments revealed that Pantoea sp. TW18 rapidly reached accumulation equilibrium at approximately 4 h with a high accumulation capacity (79.87 mg g⁻¹ at pH 4.1 and T = 310 K) for U(VI). The accumulation data of U(VI) onto Pantoea sp. TW18 can be satisfactorily fitted by pseudo-second-order model. The accumulation of U(VI) on Pantoea sp. TW18 was affected by pH levels, not independent of ionic strength. Analysis of the FT-IR and XPS spectra demonstrated that accumulated U(VI) ions were primarily bound to nitrogen- and oxygen-containing functional groups (i.e., carboxyl, amide and phosphoryl groups) on the Pantoea sp. TW18 surface. This study showed that Pantoea sp. TW18 can be considered as a promising sorbent for remediation of radionuclides in environmental cleanup.