Sustainable biopolymer-supported Ce-MOF/polyethyleneimine-guar gum composite sponge for efficient removal of ketoprofen from water: Design, mechanism, and optimization.

This research details the development of a cerium-based metal-organic framework (Ce-MOF) incorporated into a dual biopolymer matrix comprising polyethyleneimine (PEI) and guar gum (GG), producing a composite sponge known as Ce-MOF/PEI-GG. This innovative composite is specifically engineered for the efficient removal of the nonsteroidal anti-inflammatory drug ketoprofen (KTP) from water. Extensive characterization methods, including SEM-EDX, XRD, FT-IR, XPS, and BET analyses, validated the formation of a mesoporous structure with a substantial surface area of 101.29 m2/g and a point of zero charge (pHpzc) of 6.79. Batch adsorption experiments demonstrated that the pH of the solution had a significant impact on the adsorption efficiency, with the maximum absorption capacity of 564.32 mg/g recorded at pH 6. The adsorption kinetics followed a pseudo-second-order model, while the equilibrium data fit well with the Langmuir isotherm, indicating a monolayer adsorption mechanism driven by chemisorption. Additionally, thermodynamic analysis revealed that the adsorption process is both spontaneous and endothermic. Investigating the mechanisms involved showed that hydrogen bonding, π-π stacking, electrostatic interactions, and pore filling were key contributors to the adsorption process. The composite sponge also displayed exceptional reusability, retaining over 85 % of its effectiveness after six successive cycles. Optimization using the Box-Behnken design further confirmed the robustness and high efficiency of the system. In conclusion, the Ce-MOF/PEI-GG composite sponge presents a highly effective, sustainable nanomaterial, supported by biopolymers, with significant potential for mitigating water contamination caused by pharmaceutical pollutants.