Hierarchical Meso-/Macroporous Aluminum Phosphonate Hybrid Materials as Multifunctional Adsorbents

Inorganic-organic hybrid aluminum phosphonate (AlPPh) materials with hierarchical meso-/macroporous structure were synthesized by using two different kinds of organophosphonic acids: amino tri(methylene phosphonic acid) and bis(hexamethylenetriamine)-penta(methylenephosphonic acid). The preparation was accomplished both with and without the assistance of surfactant F127. All the samples possess a uniform macroporous (500-2000 nm) structure of mesoporous (4-5 nm) framework, which were characterized by SEM, TEM, N-2 sorption, XRD, TGA-DSC, elemental analysis, MAS NMR, and FT-IR spectroscopy techniques. The as-prepared AlPPh materials were used as multi functional adsorbents for the efficient removal of heavy metal ions (e.g., Cu2+) and the adsorption of proteins (e.g., lysozyme). The heavy metal ion adsorption results show that the AlPPh materials have a large adsorption capacity, comparable to those of previous reported Cu(II)-adsorbents made up of functionalized mesoporous silica. The isotherms for lysozyme adsorption are of type L (Langmuir isotherm), and different monolayer capacities were calculated using Langmuir equation. The differences between the metal ion and the lysozyme adsorption were mainly caused by the nature of inorganic ions and proteins and the interactions between the adsorbents and adsorbates. The synthesized AlPPh hybrid materials were confirmed to be useful multifunctional adsorbents for both metal ions and proteins.