Efficient Removal of Iodine from Water by a Calix[4]pyrrole-Based Nanofilm
Tingyi Wang, Xiangquan Liu, Jinglun Yang, Jiaqi Tang, Binbin Zhai, Yan Luo, Zhongshan Liu, Yu Fang
Abstract
The efficient removal of radioactive iodine from an aqueous solution is largely dependent on the adsorbent materials employed. In this work, we report a calix[4]pyrrole-based nanofilm and its application for the rapid removal of iodine from water. The nanofilm was synthesized through a confined dynamic condensation of tetra hydrazide calix[4]pyrrole with 1,3,5-tri-(4-formylphenyl) aldehyde at the air/dimethyl sulfoxide (DMSO) interface. The thickness of the obtained nanofilm is ∼35 nm, enabling fast mass transfer and a high ratio of accessible binding sites for iodine. The pseudo-second-order rate constant of the nanofilm for iodine is ∼0.061 g g –1 min –1, 3 orders of magnitude higher than most reported adsorbent materials. Flow-through nanofiltration tests demonstrated that the nanofilm has an adsorption capacity of 1.48 g g –1, a high removal efficiency, and good reusability. The mechanism study revealed that the moieties of Schiff base, pyrrole, and aromatic rings play a key role for binding iodine. We believe this work provides not only a new strategy for the efficient removal of radioactive iodine from water but also new ideas for designing efficient iodine adsorbents.