Tailoring Metal-Organic Frameworks for Polyurethane Foams to Improve Tetracycline Removal from Aqueous Solutions

For the effective removal of tetracycline (TC) from aqueous solutions, a novel Grafted Polyurethane Foam (GPUF) functionalized with iron or copper metal-organic frameworks (FeMOF-PUF and CuMOF-PUF, respectively) was created. By adjusting experimental parameters such as adsorbent dosage, initial pH, contact time, initial TC concentration, and temperature, the adsorption performance of both GPUF materials was examined. Based on the Langmuir isotherm model, the FeMOF-PUF showed a higher maximum adsorption capacity of 500.0 mg g-1 than the CuMOF-PUF which is 375.0 mg g-1. This finding suggests that the incorporation of MOF into the PUF matrix not only preserves but also improves the base material's adsorption capacity. The spontaneous and endothermic nature of the adsorption process, as demonstrated by thermodynamic measurements, points to a chemically driven interaction between TC and FeMOF-PUF. The synergistic combination of porosity, Lewis acidity of the iron sites within the MOF structure, and electrostatic interactions with TC molecules is responsible for FeMOF-PUF's excellent adsorption capability. The result shows that GPUFs, especially FeMOF-PUF, have a promising future as effective and useful adsorbents for the removal of pharmaceutical pollutants in water treatment applications.