Modification of Polyethersulfone by Chitosan Biopolymer: A New Functionalized Polymeric System and its Fast Removal Feature Toward Cr(VI) Ions and CO2 Adsorption

A novel polyethersulfone-based adsorbent modified with chitosan biopolymer (PES-R-chitosan) was successfully synthesized for the efficient removal of Cr(VI) from wastewater. Comprehensive characterization using FT-IR, FE-SEM, TGA-DTA, and BET analyses confirmed its structural integrity and enhanced surface properties. FT-IR analysis confirmed the introduction of functional groups (e.g., NH₂, OH, and CONH), and FE-SEM images showed a surface with enhanced porosity. TGA-DTA revealed a two-stage degradation process at 273 °C and 369 °C. At the same time, N₂ adsorption-desorption studies indicated a mesoporous structure with a BET surface area of 87.23 m²/g and a pore diameter of 34.12 nm. The Cr(VI) adsorption behavior and mechanisms were systematically investigated through batch experiments, optimizing key parameters such as pH, contact time, adsorbent dosage, initial Cr(VI) concentration, and the presence of competing ions. PES-R-chitosan demonstrated exceptional adsorption efficiency, reaching 222.89 mg/g of Cr(VI) uptake at room temperature. The adsorption kinetics followed the Elovich model, while the Langmuir isotherm best described the monolayer adsorption process. Even after 11 regeneration cycles, PES-R-chitosan retained an impressive 90% removal efficiency, demonstrating outstanding reusability. Furthermore, it displayed a high CO₂ adsorption capacity of up to 228 mg/g at 1 bar pressure, highlighting its potential for environmental remediation applications beyond heavy metal removal. The results highlight PES-R-chitosan’s functional versatility, thermal stability, and high adsorption potential, making it suitable for applications like heavy metal ion removal.