Facile One‐Step Fabrication of Carboxylic Acid‐Functionalized <scp>PolyHIPE</scp> for Efficient Heavy Metal and Dye Removal From Water

ABSTRACT Wastewater purification, particularly the removal of organic dyes and heavy metal ions, is critical for environmental protection and human health. Porous organic polymers (POPs) and chelating agents are common adsorbents but face limitations such as complex synthesis, high costs, or inefficiency against organic pollutants. To address this, we synthesized carboxylic acid‐functionalized polyHIPEs via water‐in‐oil emulsion by incorporating acrylic acid (AA, 0–4 wt%). FTIR confirmed AA integration, while contact angle measurements revealed enhanced hydrophilicity, and 2 wt% AA improved water adsorptions by 31% versus AA‐free polyHIPE. The materials featured open‐cell structures (15–25 μm voids), low compressive strength/modulus, and high resilience, maintaining integrity after repeated cycles. Optimal adsorption occurred at 40 mg/L initial pollutant concentration, with maximum capacities of 17.5 mg/g for Cu 2+ (pH 5.0) and 11 mg/g for Rhodamine B (RhB, pH 7.0), achieving 93% and 80% removal at 60/80 mg doses (equilibrium: 120 min). The adsorption kinetics followed a pseudo‐second‐order model, while Freundlich isotherms (higher R 2 ) suggested multilayer adsorption. After five cycles, the material retained 95% (16.8 mg/g) of Cu 2+ and 90% (10 mg/g) of RhB capacity, demonstrating exceptional reusability and selective separation potential due to distinct adsorption mechanisms.