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 m2 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 Cu2+ 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 Mn2+, Ca2+, and Mg2+ highlighted the high selectivity of the material for Cu2+ 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 Cu2+ ion removal in sustainable water purification systems.