Engineering multifunctional nanoporous polymer networks through covalent nanoparticle linking for ultrafast iodine capture

Abstract

The development of synthetic routes that maximize the surface accessibility of functional groups within porous polymeric frameworks is central to advancing their adsorption performance, especially in the context of ultrafast and efficient capture of radioactive iodine from nuclear waste streams, which remains a critical challenge. Herein, we report a sustainable synthetic strategy to construct a nanoporous polymer network (PP-PZ) by strategically crosslinking colloidal nanoparticles in water using a suitable cycloaliphatic amine crosslinker (piperazine). This approach directs interparticle chemical coupling while preserving colloidal domains within the bulk network, as evidenced by FESEM analysis. The resulting PP-PZ exhibits a high surface amine density, reflected by elevated zeta potentials, and a mesoporous (pore diameter ∼ 3 nm) texture with a surface area of 143 m² g⁻¹. These structural features collectively enable exceptional iodine uptake capacities of 12.4 g g⁻¹ (vapor), 8.5 g g⁻¹ (aqueous), and 5.3 g g⁻¹ (organic) with ultrafast adsorption kinetics in water (equilibrium ∼1 min, k₂ = 0.0235 g mg⁻¹ min⁻¹). Practical applicability is demonstrated in real wastewater treatment, in the presence of a large excess of competing ions, such as 50–100 fold, and continuous-flow column systems, enabling reuse over multiple cycles efficiently, highlighting its potential for industrial nuclear waste remediation.