Synthesis, Properties of MIL‐101(Al)‐NH₂ Polymers Capable of Absorbing Vapor, Liquid Water Simultaneously

Abstract Modified MIL‐101(Al)‐NH₂ (MIL‐101(Al)‐NH₂‐net) is used as a crosslinking agent and acrylic acid (AA) as a monomer, the MIL‐101(Al)‐NH₂‐net grafted polyacrylic acid (MIL‐101(Al)‐NH₂‐net‐g‐PAA (MAP)) composite water‐absorbent material is synthesized using the free radical polymerization method to study the application of composite absorbent materials in water collection. The structure and morphology of the composite water‐absorbent material are characterized using Fourier transform infrared spectrometry (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), Brunauer Emmett Teller (BET), and thermogravimetric analysis (TG), and the contents of ammonium persulfate (APS), MIL‐101(Al)‐NH₂‐net, and neutralization degree of AA are optimized. Under optimal conditions, the water absorption ratios of the composite materials in distilled water, tap water, and 0.9% NaCl solution are 744, 169.5, and 85.5 g g⁻¹. In addition, the properties of collecting water vapor are investigated. At 25 °C, 50% Relative Humidity (RH), 70% RH, and 90% RH, the MAP water vapor adsorption capacity is 0.0312, 0.5760, and 1.6856 g g⁻¹, respectively. The water vapor adsorption of MIL‐101(Al)‐NH₂ and MIL‐101(Al)‐NH₂ self‐polymerization products are 0.025 and 0.1278 g g⁻¹, respectively. The result showed that autopolymerization can improve the water vapor adsorption performance.