High surface area titanium phosphonate materials with hierarchical porosity for multi-phase adsorption

Abstract

Inorganic–organic hybrid titanium phosphonate materials with a hierarchically-porous structure were synthesized by a mild solvent evaporation strategy using 1-hydroxyethylidene-1,1-diphosphonic acid as an organophosphorus coupling molecule. The preparations were accomplished with the use of triblock copolymers F127 and P123 as structure-directing agents. All the samples possessed a macroporous morphology of the mesoporous framework with a high surface area, and were characterized by SEM, TEM and N₂ sorption analysis. The hydroxyethylidene-bridged organophosphonate groups were homogeneously incorporated into the network of the hierarchical porous solid, as revealed by FT-IR, MAS NMR, TGA-DSC and XPS measurements. The hybrid materials were used as adsorbents for the liquid phase adsorption of Cu²⁺ ions in water and the gas phase adsorption of CO₂, showing high adsorption capacity and good reusability, which makes them promising adsorbents for practical applications in environmental remediation.