Nanotrap Grafted Anion Exchangeable Hybrid Materials for Efficient Removal of Toxic Oxoanions from Water

Abstract

Water pollution has attracted worldwide significant attention ever since the finding of its harmful effects on the whole ecosystem, including human health. Although several materials are known for selective removal of specific contaminants, designing a single material that can adsorb a variety of water contaminants is still a very challenging task due to a lack of proper design strategies. Herein, we have rationally designed a new class of anion exchangeable hybrid material where the nanosized cationic metal–organic polyhedra (MOP) are embedded inside a porous covalent organic framework (COF) with specific binding sites for toxic oxoanions. The resulting hybrid material exhibits very fast and selective sequestration of high as well as trace amount of a wide range of toxic oxoanions (HAsO 4 2– , SeO 4 2– , CrO 4 2– , ReO 4 – , and MnO 4 – ) from the mixture of excessive (∼1000-fold) other interfering anions to well below the permissible drinking water limit. Moreover, the hybrid cationic nanotrap material can reduce the As(V) level from a highly contaminated groundwater sample to below the WHO permitted level.

Task-Specific Tailored Cationic Polymeric Network with High Base-Resistance for Unprecedented 99TcO4– Cleanup from Alkaline Nuclear Waste

“…Up to now, a series of cationic materials have been evaluated for 99 TcO 4 – removal. − Cationic inorganic materials, such as layered double hydroxides (LDHs), Yb 3 O­(OH )6 Cl, and NDTB-1, , have the advantages of easy preparation and low costs but possess low capture capacity and poor selectivity toward 99 TcO 4 – , which hinders their applications in actual alkaline nuclear waste streams since the concentrations of coexisting competing anions (NO 3 – , SO 4 2– , CO 3 2– , and OH – ) are several orders of magnitude higher than 99 TcO 4 – . Commercially available resins (Puroilte A530E and A532E) exhibit excellent sorption selectivity toward 99 TcO 4 – , but the slow sorption kinetics and poor radiation resistance are unavoidable issues.…”

Double Cationization Approach toward Ionic Metal–Organic Frameworks with a High Bromide Content for CO2 Cycloaddition to Epoxides

“…This work illustrates a “double click” approach for construction of IMOFs with a high ionic character. The approach can not only allow further systematic studies to probe the catalytic CEC reactions within the pores of MOFs but can also open new perspectives for the studies of IMOFs in other fields such as ion conductance , and adsorption/removal of hazardous anions. , …”

“…The approach can not only allow further systematic studies to probe the catalytic CEC reactions within the pores of MOFs but can also open new perspectives for the studies of IMOFs in other fields such as ion conductance 73,74 and adsorption/removal of hazardous anions. 23,41 ■ EXPERIMENTAL SECTION Materials. Starting materials and solvents were used as purchased from commercial suppliers.…”

“…Metal–organic frameworks (MOFs) are a relatively new class of hybrid compounds that show widely tunable porosity and functions, and they are attracting multidisciplinary attention for their versatile applications. − Heterogeneous catalysis is one of the most promising applications because MOFs can be designed to bear various endo - or exogenous catalytic ingredients. − The CEC reaction has been attempted with MOFs with accessible Lewis acid and/or base sites. − However, for most of the studied MOF catalysts (and other solid catalysts), the high catalytic activity for CEC requires the simultaneous use of a homogeneous organic halide (usually tetrabutylammonium bromide (TBAB) in large excess compared to the solid catalysts). The halide cocatalyst provides the free nucleophilic anion to open the activated epoxide ring, − but its use sacrifices the heterogeneity.…”

Ionic Covalent Organic Frameworks for Energy Devices

“…[84] COFs contain pores that form channels, through which other species can travel. Thus, COF-based composites have been formed by combining COFs with filler materials, such as polyacrylonitrile, [85] polysulfonamide, [86] metal-organic polyhedra, [87] or single-walled carbon nanotubes (CNTs). [88] Moreover, COF composites with enhanced electron conductivity have been formed by combining COFs with poly(3,4ethylenedioxythiophene) [89] or graphene/CNTs.…”