Rational Design of Multifunctional Porous Polymer via Diels–Alder ‘Click’ Reaction for Highly Efficient Removal of Microplastics from Water Matrices

The persistent nature and ecological risks of microplastics (MPs) demand advanced adsorbent materials for their highly efficient removal from water matrices. Here, we present the development of a multifunctional hydrophobic porous polymer, synthesized via ultrafast Diels–Alder “Click” reactions between a trifunctional anthracene monomer (A3) and a bis-triazolinedione (TAD) monomer (B2). The resulting cross-linked network exhibits a surface area of 135 m2/g, an average pore size of 2.6 nm, and possesses high chemical and thermal stability up to 270 °C. Hydrophobicity of the materials is evidenced with a water contact angle of ∼143°. The polymer shows remarkable adsorption performance of microplastics with an excellent adsorption capacity of 190 mg/g, with ∼99% removal efficiency within 35 min at pH 6. Wastewater purification studies further confirmed >95% removal from sewage effluents, rivers, lakes, and seawater, while a column-based setup reached 98% efficiency in MP-spiked water. Notably, the material retained its activity over five regeneration cycles without any significant loss. This work highlights the potential of TAD-based Diels–Alder chemistry to create multifunctional hydrophobic adsorbents suitable for dynamic flow systems and tertiary wastewater treatment, enabling efficient microplastic removal across diverse water matrices.