Amine appended bimetallic metal-organic framework (MOF-74) for carbon dioxide capture and method of preparation thereof

A metal-organic framework (MOF),

• including:
• cadmium;
• magnesium;
• linking units of 2,5-dihydroxyterephthalic acid complexed with cadmium and magnesium;
• and
• units of,
• wherein the units of guanidine are reacted with the linking units of 2,5-dihydroxyterephthalic acid,
• wherein the MOF is in the shape of spherical particles with a longest dimension of 50 to 250 nanometers (nm),
• wherein the MOF includes units of guanidine in an amount of 8 to 12 wt. % based on a total weight of the MOF.

A metal-organic framework (MOF),

• including:
• cadmium;
• magnesium;
• linking units of 2,5-dihydroxyterephthalic acid complexed with cadmium and magnesium;
• and
• units of guanidine in an amount of 1 to 25 percent by weight (wt. %) based on a total weight of the MOF,
• wherein the units of guanidine are reacted with the linking units of 2,5-dihydroxyterephthalic acid,
• wherein the MOF is in the shape of spherical particles with a longest dimension of 50 to 250 nanometers (nm),
• wherein the MOF is made by a process including:
• dissolving a 2,5-dihydroxyterephthalic acid, a cadmium salt, and a magnesium salt in a solvent mixture to form a first solution;
• sonicating the first solution for 5 to 15 minutes (min);
• heating the first solution to a temperature of 120 to 140 degrees Celsius (° C.) for 20 to 28 hours (h) to form a first product;
• washing and drying the first product;
• mixing the first product with a guanidine salt in a polar organic solvent to form a second mixture;
• refluxing the second mixture at a temperature of 50 to 70° C. for 20 to 28 h to form a second product;
• washing and drying the second product to form the MOF,
• wherein a molar ratio of cadmium salt to the magnesium salt is 1:2 to 2:1.