A stable Zr(IV)-MOF for efficient removal of trace SO from flue gas in dry and humid conditions.

Obtaining suitable adsorbents for selective separation of SO from flue gas still remains an important issue. A stable Zr(IV)-MOF (Zr-PTBA) can be conveniently synthesized through the self-assembly of a tetracarboxylic acid ligand (HL = 4,4',4'',4'''-(1,4-phenylenebis(azanetriyl))tetrabenzoic acid) and ZrCl in the presence of trace water. It exhibits a three-dimensional porous structure. The BET surface area is 1112.72 m/g and the average pore size distribution focus on 5.9, 8.0 and 9.3 Å. Interestingly, Zr-PTBA shows selective adsorption of SO. The maximum uptake reaches 223.21 cm/g at ambient condition. While it exhibits lower adsorption uptake of CO (30.50 cm/g) and hardly adsorbs O (2.57 cm/g) and N (1.31 cm/g). Higher IAST selectivities of SO/CO (21.9), SO/N (912.7), SO/O (2269.9) and SO/CH (85.0) have been obtained, which reveal its' excellent gas separation performance. Breakthrough experiment further confirms its application for flue gas deep desulfurization both in dry and humid conditions. Furthermore, the gas adsorption results and mechanisms have also been studied by theoretical calculations.