Titania-phosphonate hybrid porous materials: preparation, photocatalytic activity and heavy metal ion adsorption

Organic-inorganic hybrid materials of porous titania-phosphonate were synthesized using organically bridged tetra-or penta-phosphonates. Claw molecules of ethylene diamine tetra(methylene phosphonic acid) and diethylene triamine penta(methylene phosphonic acid) were anchored to the titania network homogeneously. The synthesized titania-phosphonate hybrids possess irregular mesoporosity formed by the assembly of nanoparticles in a crystalline anatase phase, revealed by the measuement of X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy. The structure and chemical states of the materials were characterized by chemical analysis, FT-IR, MAS NMR, XPS and thermogravimetric analysis, revealing the integrity of organic groups inside the framework. The optical properties, catalysis and adsorption performances were also investigated. These porous titania-phosphonate materials exhibited high photocatalytic activity in photodecomposition of Rhodamine B dye molecules whether under UV or visible-light irradiation, and a large capacity for selective adsorption of Cd(II) ions, making them promising adsorbents and photocatalysts for practical applications including wastewater cleanup.