Green‐Engineered Cd–Cr‐Embedded Cellulose Hybrid Composite for Adsorptive Removal of Linagliptin From Water and Antioxidant Activity

Pharmaceutical residues are increasingly being detected in aquatic environments, raising concerns regarding their persistence and potential ecological impacts. In the present work, a Cd–Cr cellulose nanocomposite was synthesized through a green route using Citrus reticulata (kinnow) seed extract as a natural reducing and stabilizing medium. Structural and physicochemical properties of the synthesized material were examined using FTIR, UV–Vis spectroscopy, XRD, SEM–EDX, TEM, DLS, zeta potential, and XPS analyses. The XRD results indicated a crystallite size of 26.5 nm, whereas TEM micrographs revealed particle sizes ranging from 70 to 100 nm. A zeta potential value of −15.3 mV suggested a negatively charged surface with favorable characteristics for adsorption. Batch adsorption experiments demonstrated effective removal of linagliptin from water, with a maximum removal efficiency of 95% under optimized conditions. Equilibrium data were best represented by the Langmuir model (R 2 = 0.9742), yielding a maximum adsorption capacity of 21.6 mg g −1 , while the adsorption kinetics followed the pseudo‐second‐order model (R 2 = 0.9792). The nanocomposite also exhibited notable concentration‐dependent scavenging activity against DPPH and ABTS radicals. These findings demonstrate that the synthesized Cd–Cr cellulose nanocomposite combines adsorption efficiency with antioxidant functionality, making it a promising material for the treatment of pharmaceutical‐contaminated water.