Organic Linker Effect on Iodine Adsorption in Thorium‐Based UiO‐66‐Type Metal Organic Frameworks

Thorium‐based UiO‐66/67 metal‐organic frameworks (MOFs) are studied among the most promising radioactive iodine traps to achieve sustainable clean nuclear energy. Here, seven MOFs, namely, Th‐BDC, Th‐1,4‐NDC, Th‐ADC, Th‐ABDC, Th‐2,6‐NDC, Th‐BiPhDC, and Th‐BiPyDC (where BDC= benzene‐1,4‐dicarboxylic acid; 1,4‐NDC = naphthalene‐1,4‐dicarboxylic acid; ADC = anthracene‐9,10‐dicarboxylic acid; ABDC = 2‐aminobenzene‐1,4‐dicarboxylic acid; BiPhDC = 1,1′‐biphenyl‐4,4′‐dicarboxylic acid; BiPyDC = 2,2′‐bipyridyl‐5,5′‐dicarboxylic acid), are synthesized and characterized employing powder X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, surface area measurement, Fourier‐transform infrared, and Raman spectroscopy. MOFs having large linker lengths, namely, Th‐2,6‐NDC, Th‐BiPhDC, and Th‐BiPyDC, are collapsed during solvent drying. I 2 vapor adsorption studies are carried out, and the I 2 @MOFs are characterized. MOFs with similar linker lengths but different numbers of aromatic rings (Th‐BDC, Th‐1,4‐NDC, Th‐ADC) have similar SSA (specific surface area) normalized I 2 adsorption capacities (≈0.9 g/g). Among the UiO‐66‐type MOFs, ThBDC stands out to have highest I 2 adsorption capacity of ≈1.7 g/g due to the presence of an electron‐donating group on the aromatic ring. This study provides the rationale to design better MOFs for I 2 adsorption and gives insight that the electron density modulated by the electron‐donating group on the linker is more significant than increasing the number of aromatic rings in UiO‐66 family.