Synthesis of N-containing porous aromatic frameworks via Scholl reaction for reversible iodine capture

The effective capture of radioactive volatile iodine (I-131 and I-129) from nuclear waste stream is of vital significance. In this work three kinds of porous organic frameworks (POFs) knitting with N-containing building units were constructed via cost-effective and maneuverable Scholl reaction. The obtained PAFs exhibited moderate porosity and satisfying thermal stability. With coexistence of open porous structure, the electron-rich amino group featured with pi-pi interactions was found to improve the affinity to iodine, and the iodine uptake capacities were 408 wt%, 335 wt% and 268 wt% when the prepared POFs of P-DPDA, P-TPB and P-PC were employed for the adsorption experiments. The results were superior to most of the porous adsorbents including zeolite, metal organic frameworks (MOFs) and porous organic polymers (POPs). Iodine adsorption capacities of 289.50 mg g(-1) (for P-DPDA), 194.63 mg g(-1) (for P-TPB) and 259.69 mg g(-1) (for P-PC) in organic solution were achieved, and the adsorbed iodine molecules could be released to ethanol. Such promising and cost-effective materials can be envisaged for application in the field of nuclear waste management.

Automated summary

Three porous organic frameworks (POFs) were constructed via a cost-effective Scholl reaction with N-containing building units, showing moderate porosity and satisfactory thermal stability. The electron-rich amino group in the POFs improved the affinity to iodine, achieving iodine uptake capacities superior to most porous adsorbents. The promising and cost-effective materials could be used for nuclear waste management applications.