Ionic liquid-functionalized magnetic polystyrene nanoparticles for efficient removal of methyl violet and acid red 88 from aqueous media

Abstract

Concerns about color pollution in aquatic environments have raised awareness of its environmental impact. Consequently, researchers are increasingly focused on removing colored pollutants due to their harmful effects on health and ecosystems. Metformin-modified magnetic polystyrene nanoparticles [MPS-DAB-MET].2Cl- were created as a novel solid catalyst supported by ionic liquids, and their structure was analyzed using various techniques, including TGA, FT-IR, XRD, VSM, SEM, EDS mapping, and CHN analyses. The adsorption capacity of the synthesized [MPS-DAB-MET].2Cl- was evaluated for its ability to remove Methyl Violet (MV) and acid red 88 (AR88). As a nano adsorbent, [MPS-DAB-MET].2Cl- effectively adsorbs both dyes under optimal conditions: a dye concentration of 20 mg/L, an adsorbent dosage of 20 mg, a pH of 7, and a temperature of 25 °C. The adsorption of MV and AR88 dyes was analyzed using the Langmuir, Freundlich, and Temkin isotherm models. The findings indicated a strong correlation with the Langmuir isotherm, achieving a remarkably high regression coefficient (R2 > 0.997) when compared to other models. Additionally, the maximum adsorption capacities were determined to be 434.78 mg/g for the dye MV and 476.19 mg/g for AR88. Kinetic analysis revealed that the process followed a pseudo-second-order model for both dyes, suggesting that physical adsorption was the primary mechanism affecting the adsorption rate. The thermodynamic study demonstrated that the adsorption processes were exothermic for MV and endothermic for AR88. The results showed that [MPS-DAB-MET].2Cl- is an affordable and eco-friendly nano adsorbent that effectively and efficiently removes cationic and anionic dyes from aqueous solutions.