Synthesis of Biodegradable Nano‐Biopolymeric Polyacrylamide‐g‐Wheat Straw Fibrous (PAM‐g‐WSF) Hydrogel for Sustainable Remediation of Cu(II) and Cr(VI): Reutilization Into Catalytically Active Cu Nanoparticles

ABSTRACT This study has focused on synthesis of nanoscalic fibrous biopolymer ( PAM‐g‐WSF) and its application for remediation for Cu(II) and Cr(VI) ions from wastewater. New Polymer prepared via graft co‐polymerization of nano‐cellulosic wheat straw fibers as cellulose rich source with a polyacrylamide/bisacrylamide framework in presence of redox initiator system. The synthesized biopolymer hydrogel was characterized using FTIR, FESEM, TEM, EDX, and XRD and evaluated for heavy‐metal remediation using AAS. The maximum removal efficiencies achieved were 97.16% Cu 2+ at pH 5.7 and 93.38% for Cr 6+ at pH 3.7. The maximum adsorption capacities ( Q max ) were determined using the Langmuir model, yielding values of 48.48 for Cu 2+ and 88.565 for Cr 6+ at optimal adsorbent doses of approximately 150 and 200 mg/L, respectively, with equilibrium contact times of 90 min for Cu(II) and 60 min for Cr(VI). On further study of adsorption kinetics best described by pseudo‐second‐order model, indicating chemisorption mechanism. Equilibrium data showed superior fit with the Freundlich isotherm with K F values of 4.62 for Cu 2+ and 2.18 for Cr 6+ and R 2 values (0.9985 for Cu 2+ and 0.9994 for Cr 6+ ). Overall, the PAM‐g‐WSF nano‐hydrogel exhibited excellent adsorption capability for the efficient sequestration of Cu(II) and Cr(VI) ions.