Rapid microwave assisted RAFT synthesis of amphiphilic HEMA-co-AMPS copolymers for high performance Cu2+ and Cr6+ removal from water

An amphiphilic HEMA-co-AMPS copolymer was synthesized through microwave-assisted RAFT polymerization using a rapid and energy-efficient approach. Comprehensive characterization confirmed successful copolymer formation, high structural stability, and the presence of abundant negatively charged sulfonate groups. The copolymer exhibited excellent adsorption performance toward Cu²⁺ and Cr⁶⁺ ions, achieving maximum capacities of 165 mg g⁻¹ and 115 mg g⁻¹, respectively, within ≤ 3 h. Adsorption followed a pseudo-second-order kinetic model, while equilibrium data were best described by the Langmuir model for Cu²⁺ and the Freundlich model for Cr⁶⁺. Thermodynamic analysis indicated spontaneous adsorption, with Cu²⁺ uptake occurring through an endothermic process and Cr⁶⁺ uptake proceeding exothermically. The copolymer retained more than 87% of its initial adsorption capacity after multiple cycles, demonstrating strong reusability. Overall, these findings highlight microwave-assisted RAFT polymerization as an efficient and sustainable strategy for producing high-performance polymeric adsorbents for water treatment applications.