Enhanced iodine capture by incorporating anionic phosphate unit into porous networks

Although significant advance has been achieved in developing porous organic polymers for effective iodine capture, the underlying principle for the adsorption behavior is not fully understood. Herein, analogous anionic porous networks (IPN-CSUs) bearing phosphate unit were fabricated via a one-pot Friedel-Crafts alkylation, in which heteroatom-containing triphenylamine (N) and 9,10-anthraquinone (O) were picked up as co-building blocks. The compositions were simply regulated, and the obtained networks displayed rich porous structure, thereby offering high sorption capability towards iodine in cyclohexane solution. Specifically, the anionic networks exhibited an improvement up to 122.4% in capturing iodine compared to the corresponding neutral counterpart. The adsorption performance of IPN-CSU-1 (N incorporated) in iodine vapor reached 357 wt%, which is comparable to the state-of-art networks possessing ultra-high specific surface area and the performance maintained at about 82% of the original value after five consecutive cycles. In addition, the combination of experimental and theoretical computational simulations highlights the prominent role of negatively charged phosphate group in efficient iodine capture.