Enhanced and Selective Removal of Copper Ions via PEG-Cross-Linked TETA-Functionalized Poly(methyl acrylate) Networks

Designing polymer-based adsorbents with high adsorption capacity and tailored selectivity toward specific metal ions continues to pose a major challenge in water treatment. To address this, we report the synthesis of a poly(methyl acrylate) (PMA) adsorbent cross-linked with polyethylene glycol (PEG) and functionalized with triethylenetetramine (TETA). The polymerization was carried out via atom transfer radical polymerization (ATRP) using a glycerol-derived trifunctional initiator. The resulting PMA–PEG-TETA particles exhibit a specific surface area of 45.4 m 2 g –1 and a mesoporous structure with pore sizes ranging from 2 to 20 nm. Dynamic light scattering revealed hydrodynamic diameters between 100 and 225 nm, while ζ-potential measurements across various pH values characterized the surface charge behavior. The adsorbent was evaluated for Cu 2+ ion removal from aqueous media under varying conditions of pH, dosage, contact time, and temperature. Isotherm analysis indicated that adsorption followed the Langmuir model, suggesting monolayer coverage with a maximum adsorption capacity of 333.3 mg g –1 . Kinetic modeling confirmed that chemisorption was the dominant adsorption mechanism, likely driven by coordination bonding. Thermodynamic parameters derived via the van’t Hoff equation revealed a spontaneous and exothermic process. Competitive adsorption studies with Mn 2+, Ca 2+, and Mg 2+ highlighted the high selectivity of the material for Cu 2+ ions. Moreover, recyclability tests demonstrated that the adsorbent retained its performance over at least three cycles without significant loss. These findings underscore the potential of PMA–PEG-TETA as a selective, efficient, and reusable platform for Cu 2+ ion removal in sustainable water purification systems.