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

摘要

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-DOBDC~(4-)= 4,6-dioxo-l,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-DOBDC~(4-)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.