Phenidone‐Functionalized Hyper‐Cross‐Linked Resins: Synthesis, Adsorption Behavior, Mechanistic Insights and Reusability for Salicylic Acid Removal From Aqueous Solutions

Functionalized hyper‐cross‐linked polymers are widely acknowledged as high‐performance adsorbents for organic‐laden wastewater owing to their specific affinity toward organic contaminants. Herein, phenidone‐functionalized hyper‐cross‐linked resins (PND‐HCMPs) were fabricated from chloromethylated polystyrene resins (CMPs) via sequential nucleophilic substitution, followed by Friedel‐Crafts alkylation reactions. The adsorption behavior of PND‐HCMPs toward salicylic acid (SA) was systematically investigated. Batch adsorption results revealed that the fitted maximum adsorption capacity of PND‐HCMPs for SA reached 210.1 mg/g at 308 K, and equilibrium isotherm data were well fitted to the Freundlich model ( R 2 = 0.9978). Remarkably, adsorption equilibrium was achieved within 60 min, and kinetic data were excellently described by the pseudo‐second‐order model ( R 2 = 0.9965). Adsorption was facilitated under acidic conditions, and the SA removal efficiency reached 99.1%. Besides, the coexisting inorganic salt Na 2 SO 4 in tap water facilitated SA adsorption via the salting‐out effect. Cyclic regeneration experiments verified the acceptable recyclability of PND‐HCMPs. Collectively, PND‐HCMPs show competent SA removal performance in aqueous solutions and are applicable for practical organic wastewater treatment.