Sorption and removal of iodate from aqueous solution using dried duckweed (Landoltia punctata) powder

Dried duckweed (Landoltia punctata) powder is applied to remove IO₃^- from aqueous solutions under various conditions. The results indicate the K_d is 150 ml g^-1 under general conditions. The sorption kinetics follow the pseudo-second-order equation, and the isotherm is well described by the Freundlich model. Hydroxyl and carbonyl groups contribute to IO₃^- sorption by ion-exchange, electrostatic attraction and redox reactions. Spectroscopic analyses prove that IO₃^- is reduced to I₂ and I^- by hydroxyl groups. These results demonstrate that duckweed (Landoltia punctata) is a promising biosorbent for environmental remediation of radioactive iodine pollution. (author)