Related Experiment Video
Updated: May 22, 2026

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
Local polarity modulation in triangular pores of covalent organic frameworks for iodine capture from water
Mengjie Hao1, You Wu1, Juyao Zhang1
1College of Environmental Science and Engineering, North China Electric Power University, Beijing, P.R. China.
Abstract:
Radioactive iodine from nuclear fission processes can enter water systems in various ways, adversely affecting human health and the environment. Herein, we construct a series of covalent organic frameworks (COFs) with triangular pores and different local polarities for efficient iodine (I2 + I- ⇌ I3-) capture from aqueous solution. Triangular pores containing weakly polar units show a strong affinity for nonpolar iodine via hydrophobic interactions, whilst the periodically ordered frameworks and intrinsic interlayers based on aromatic moieties and nitrogen-containing groups capture I2 and I3- through van der Waals forces and charge transfer. COF-1 with weak local polarity delivers a high iodine (131I) adsorption capacity, fast adsorption kinetics, and excellent selectivity in tap water, groundwater, and seawater. Moreover, COF-1 exhibits an exceptional trace iodine removal efficiency (from ~200 ppb to below ~65.9 ppb in tap water and ~58.3 ppb in groundwater), making it a promising adsorbent for efficiently treating aqueous iodine waste streams.
More Related Videos
Related Concept Videos
Intermolecular Forces
Molecular Shape and Polarity
Bond Polarity, Dipole Moment, and Percent Ionic Character
Covalent Bonds
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
Aquaporins
Ion Exchange

