High Removal Efficiency of Radioactive Iodine with In Situ-Synthesized AgO-Mg(OH) Plate Composites.

To promote the capacity of adsorbing radioactive iodine (I) in acid and alkaline situations, a high-removal-efficiency adsorbent based on silver oxide (AgO) and magnesium hydroxide (Mg(OH)) was synthesized by the in situ method. To determine the mechanism of this novel absorbent, batch experiments related to the temperature, pH, competitive ion (Cl), and kinetic analysis were carried out. The results showed that the AgO-Mg(OH) plate composites had high adsorption capacity and efficiency for I (409 mg/g, 25 °C) with a wide range of pH values (3-9). In addition, the adsorption time from the initial concentration to I removal (97.36%) was only 20 min. Competitive ion experiments depicted that Cl influenced the capacity of adsorbing I. The value of the pseudo-second-order model and regression factor were 7.86 × 10g mg min and 0.999 at 25 °C, respectively. The kinetics and XPS results proved that the mechanism of adsorption was chemical adsorption. Compared with other commercial adsorbents, the AgO-Mg(OH) plate composites had potential for application in nuclear wastewater treatment with low cost and high efficiency.