Experimental study on adsorption removal of SO2 in flue gas by defective UiO-66

Metal-organic frameworks (MOFs) with a high specific surface area, an adjustable pore structure, and functionalized pore environment have a broad application prospect in gas adsorption and separation. In this work, a series of defective UiO-66 (UiO-66-monocarboxylic acid) samples were prepared by adding different monocarboxylic acids during the synthesis of UiO-66. UiO-66-monocarboxylic acid samples (UiO-66-formic acid, UiO66-acetic acid, UiO-66-benzoic acid, UiO-66-acrylic acid, and UiO-66-cyanoacetic acid) had a high specific surface area (1200-1400 m(2)/g) and a good thermal stability (560?). In the desulfurization experiment of simulated flue gas (SO2/CO2/O-2/N-2, 0.3/10.0/5.5/84.2 vol%), the breakthrough time of UiO-66-cyanoacetic acid for SO2 was higher (194 min/g), and the selectivity of SO2/CO2 reached 33.8. Through optimizing the moles of cyanoacetic acid added, the breakthrough time of SO2 on 18-UiO-66-cyanoacetic acid increased to 251 min/g. At a pressure of 1.0 bar and a temperature of 298 K, the adsorption capacity of SO2 by 18-UiO-66-cyanoacetic acid reached 762.1 mg/g. In addition, the adsorption behavior of 18-UiO-66-cyanoacetic acid for SO2 was considered as a combination of chemical and physical adsorption, and fractional chemisorption sites was provided by cyanoacetic acid.

Automated summary

Metal-organic frameworks (MOFs) are promising materials for gas adsorption and separation due to their high specific surface area, adjustable pore structure, and functionalized pore environment. By introducing different monocarboxylic acids during the synthesis, a series of defective UiO-66 samples were prepared with high specific surface area and good thermal stability. Among them, UiO-66-cyanoacetic acid showed the highest breakthrough time for SO2 in the desulfurization experiment of simulated flue gas.