Recycling of poly-(methyl methacrylate) waste sheets to synthesize catalyst-free bi-functional cation-exchange resin for sequestering of toxic pollutant

A simple and green method for the recovery of methyl methacrylate (MMA) has been developed by recycling waste sheets of poly-(methyl methacrylate) without using any catalyst. The liquefaction yield was 97.33% while the purity of recovered MMA was up to 92%. The recovered monomer utilized for the synthesis of methylmethacrylate-copolymer-divinylbenzene at 20% cross-linking in the presence of different porogens (methyl isobutyl ketone, cyclohexane, toluene, and cyclohexanone) by suspension polymerization. The same copolymer was also synthesized but with different cross-linking percentages such as 4, 10, 15, 20, 25, 30, and 40% in the presence of a single porogen (methyl isobutyl ketone). Different copolymers having pore volumes in the range of 0.120–0.682 mL/g were obtained. The pendant –COOCH₃ groups within the polymeric chain were converted to –COOH groups via acid hydrolysis, accompanied by the attachment of –SO₃H groups to phenyl rings. ATR-FTIR, UV–Vis spectrometry, and HPLC techniques were used for qualitative and quantitative analyses of –COOH and –SO₃H groups. The obtained results were compared with copolymers and resin synthesized using commercial MMA, displaying similar behavior. The resin derived from the recovered monomer was utilized for Co²⁺ ion removal at various pH, demonstrating excellent removal performance.