Herein, a biocompatible nanocomposite based on guar gum (GG-CuMn2O4) was successfully synthesized and utilized for the elimination of toxic Allyl 2,4,6 tribromophenyl ether (ATE), a commonly used plastic additive. The research involved the green fabrication of CuMn2O4, which was then integrated into the polymeric matrix of guar gum to form GG-CuMn2O4 nanocomposite. The successful creation of the green-synthesized nanocomposite coated with a polymeric matrix at the nanoscale was confirmed by characterization. PXRD analysis revealed a semi-crystalline structure, while microscopic examinations committed the encapsulation of CuMn2O4 within a sheet-like structure in nanorange (1–100 nm). Incorporating the CuMn2O4 nanocomposite into the GG gel matrix reduced the likelihood of nanocomposite leaching, thereby enhancing material efficiency and biocompatibility. Highest removal of ATE (95 %) was achieved at a concentration of 5 mg L−1 with a catalytic dose of 10 mg, pH 7, and in the presence of Sunlight. The removal of the pollutant followed first-order kinetics, exhibiting Langmuir adsorption. The study examined the release dynamics of ATE from both underwater-expanded packaging materials and electrical wire components over various time intervals, concurrently assessing the degradation characteristics of the leached ATE. LC-MS analysis has corroborated that GG-CuMn2O4 demonstrates a profound capacity in disassembling intricate, hazardous pollutant structures into metabolites of enhanced safety, catalytically driven by Sunlight. The polymeric GG-CuMn2O4 nanocomposite exhibited remarkable reusability for up to ten consecutive cycles and advocated its sustainability efficiency and industrial applications.