Effect of Functional Groups on the I2 Sorption Kinetics of Isostructural Metal–Organic Frameworks

Abstract

In this work, the effect of functional groups on I2 sorption kinetics is investigated using two different types of isostructural metal-organic frameworks, UiO-66-X series (X = H, Br, NO2, NH2, (OH)2, and (COOH)2) and M2(m-DOBDC) series, (M = Co2+, Mg2+, and Ni2+; m-DOBDC4− = 4,6-dioxo-1,3-benzenedicarboxylate). Among the UiO-66-X series, UiO-66-(COOH)2 exhibits the fastest sorption kinetics and the highest sorption capacity due to dipole-induced dipole interactions between carboxylic acid groups and I2 molecules. In addition, faster I2 chemisorption is observed in M2(m-DOBDC) because of electrophilic aromatic substitution of m-DOBDC4− with I2. The I2 sorption mechanisms are further supported by fitting the I2 adsorption kinetics data to pseudo-first-order and pseudo-second-order kinetic models. © 2021 Korean Chemical Society, Seoul & Wiley-VCH GmbH