The dual capture of AsV and AsIII by UiO-66 and analogues† †Electronic supplementary information (ESI) available: Includes synthesis and preparation of UiO-66 and analogues along with characterization data (PXRD, TGA analysis, N2 isotherms, DRIFTS, XPS analysis), Lagergren kinetic data fittings, leaching studies, recycling studies, and other relevant observations. See DOI: 10.1039/c6sc00490c Click here for additional data file.

Metal organic frameworks (MOFs) are highly porous and crystalline coordination polymers that can be synthesized from a wide variety of metal-cluster nodes and a diverse selection of multitopic organic linkers. As a result, they are highly tailorable and different combinations of functionalities can be incorporated into the nodes and the linkers in an orthogonal manner. Not surprisingly, these materials have recently garnered increasing interest in capture-and-release studies, where the metal cluster nodes were tailored to capture/release phosphonate-based substrates or the organic linkers were used to sequester toxic heavy metals. These precedents led us to propose that MOFs can be used as a model platform to demonstrate the capture of toxic anionic arsenates (As) and neutral arsenites (As), both of which exist in ground water (pH 6–8.5), in a complementary fashion (Fig. 1); the node can be used for binding anionic As and the linkers can be functionalized to capture neutral As. Such a design can serve as a versatile strategy for developing materials that efficiently capture multiple pollutants or toxic agents that exist as diverse species in certain environments. Given their high chemical stability and hydrophilicity, we deemed MOFs with hexazirconium oxo hydroxo (Zr6O4(OH)4) cluster nodes, such as UiO-66, to be suitable model targets for modications to capture both As and As from aqueous media. We predicted strong interactions between the nodes of