| Abstract: | Zirconium in aqueous flows was moderately biomineralized by immobilized Citrobacter N14 cells, in the form of gel‐like deposits, probably comprising a mixture of zirconium hydrogen phosphate (Zr(HPO4)2) and hydrated zirconia (ZrO2). The simultaneous presence of uranyl ion (UO ) did not facilitate zirconium deposition and the biomineralization of uranium itself as HUO2PO4 was repressed by zirconium in the presence of excess inorganic phosphate, liberated enzymatically. Nickel (Ni2+) was not significantly removed from aqueous flows by sorption into cell‐bound zirconium deposits, although cell‐bound hydrogen uranyl phosphate (HUP) facilitated nickel removal via intercalative ion exchange into its polycrystalline lattice. A preformed layer of HUP also promoted zirconium removal, at 100% efficiency at pH 2.6, maintained over 38 column fluid‐volumes before saturation. © 1999 Society of Chemical Industry |
