Superhydrophobic Phosphonium Modified Robust 3D Covalent Organic Framework for Preferential Trapping of Charge Dispersed Oxoanionic Pollutants

Abstract

Charge dispersed and less hydrophilic anionic pollutants are often difficult to be preferentially captured by common cationic framework materials. A gamma radiation modification approach is employed to anchor a superhydrophobic phosphonium‐containing coating on a robust crystalline 3D covalent organic framework (COF). By regulating the surface hydrophobicity, the prepared 3DCOF‐g‐VBPPh3Cl is endowed with a strong affinity for charge dispersed and less hydrophilic oxoanions, such as MnO4−, TcO4− and ReO4−, to surmount the Hofmeister bias, which much favors remediation of oxoanionic pollutants in complex aqueous systems. Batch and column experiments with 3DCOF‐g‐VBPPh3Cl in both tap water and simulated groundwater are performed, and rapid sequestration is achieved with removal efficacy up to 99.995%, record‐high distribution coefficient of 1.0 × 108 mL g−1, and desirable priority over competing anions such as Cl−, SO42−, HCO3−, and NO3−, confirming promise for remediation of charge dispersed anionic pollutants. Theoretical calculations reveal a mechanism of preferential capture based on electrostatic and dispersion interaction between charge dispersed anions and 3DCOF‐g‐VBPPh3Cl that effectively competes with solvation of the aqueous anions.

Rapid and selective removal of toxic and radioactive anionic pollutants using an ionic covalent organic framework (iCOF-2)

“…For this important application, iCOF-2 should be stable in a high radiation environment. To check the radiation stability of iCOF-2, its sample was exposed to gamma ray irradiation at a dose rate of 650 Gy per hour using a 60 Co source. Irradiation experiments were also performed at various other dose levels, such as 50 kGy, 100 kGy, 200 kGy and 300 kGy.…”

“…Anions such as Cl − , Br − , NO 3 − and SO 4 2− are often present (in large excess) along with 99 TcO 4 − in highly radioactive waste solutions as well as in groundwater of contaminated zones. 36,56,58–62 In this context, the removal performance of MnO 4 − /ReO 4 − was studied in the presence of various interfering anions (Fig. 3d for ReO 4 − and Fig.…”

“…The selective capture of pollutants is a key factor while exploring the practical application of an adsorbent. Anions such as Cl − , Br − , NO 3 − and SO 4 2−are oen present (in large excess) along with 99 TcO 4 − in highly radioactive waste solutions as well as in groundwater of contaminated zones 36,56,[58][59][60][61][62]. In this context, the removal performance of MnO was studied in the presence of various interfering anions (Fig.3dfor ReO…”

Anion−π Interaction Powered Perrhenate Recognition and Extraction in Aqueous Media

“…Until now, many different approaches have been developed for TcO 4 – /ReO 4 – removal. ,− Ion exchange and reductive immobilization are the routine methods currently applied in anion removal, , but the development of TcO 4 – /ReO 4 – anion-sorbent materials with high uptake capacity, fast kinetics, and selectivity is still the research hotspot and frontier trend. Specifically, recognition-based anion separation based on supramolecular receptors can provide sorbent materials with better affinities, recyclabilities, and selectivities for their applications under real situations.…”

Highly Selective Adsorption of 99TcO4−/ReO4− by a Novel Polyamide-Functionalized Polyacrylamide Polymer Material

“…The most studied adsorbents are metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). They have a high specific surface area and many pores, so they have high a saturated adsorption capacity for 99 TcO 4 − , but they are insufficient for the treatment of 99 TcO 4 − in environments with high acidity and acidity [ 14 , 15 , 16 , 17 , 18 , 19 ]. Ion exchange resins are other polymer materials that have been widely studied.…”