Chemically Robust Urea-Tethered Adaptable Ionic Porous Nanotrap: Ultrafast Organic and Inorganic Arsenic Water Decontamination

Abstract

The poultry industry widely makes use of organoarsenic compounds as feed additives. Consequently, their release into wastewater can be the genesis of serious poisoning of the ecosystem. Roxarsone (ROX), a typical aromatic organoarsenical, on account of being an emerging micropollutant, is imperative to remove from water as it can be degraded into extremely toxic inorganic arsenic compounds poisoning the ecosystem. Therefore, it is topical to design and develop potent materials with high affinity toward organic and inorganic arsenic species, which still remains very challenging. Herein, we report the amalgamation of ionicity and anchoring-adaptable functionality tethered covalently to ensure structural robustness in a single material. IPiPOP-3U bearing a urea functionality-based “nano-trap” displayed outstanding organoarsenic adsorption competence in terms of ultrafast uptake (up to 99% removal in 30 s) and an excellent capacity (833 mg g^–1 for ROX). The practical applicability of IPiPOP-3U was verified with trace concentration studies and flow-through experiments. It also displayed unaltered sorption efficiency in various real-world water samples, while the mechanistic aspects were expressed with the aid of an extended X-ray absorption fine structure (EXAFS) in combination with theoretical studies. The thermodynamic feasibility of ROX capture by IPiPOP-3U was further probed by isothermal titration calorimetry (ITC). Additionally, IPiPOP-3U also showed remarkable performance toward the removal of inorganic arsenic, i.e., arsenate (HAsO₄^2–), with a high uptake capacity (264 mg g^–1) and excellent cycling performance (up to 10 cycles).