Related Experiment Video
Updated: Sep 18, 2025
Preparation of Expanded Chitin Foams and their Use in the Removal of Aqueous Copper
Published on: February 27, 2021
Enhanced Cr(VI) removal by magnetite-modified chitosan-vanillin biopolymer: Mechanistic insights, statistical
Tarek E Khali1, Esraa El-Meligy1, Laila A Mohamed2
1Chemistry Department, Faculty of Science, Alexandria University, 2 Bagdad Street, P.O. Box 2, Moharrem Beck, 21321 Alexandria, Egypt.
Abstract:
Chitosan (CS) biopolymer and vanillin were used to prepare two biosorbents: CS-Vanillin and Fe₃O₄@CS-Vanillin. Their adsorption mechanisms were examined using batch adsorption studies and characterized by FT-IR, BET, TGA, XRD, XPS, EDX, and SEM analyses. The optimal pH values for adsorption were 6 for CS-Vanillin and 3 for Fe₃O₄@CS-Vanillin. Both adsorbents followed the Freundlich isotherm model, indicating multilayer adsorption, with capacities of 57 mg/g for CS-Vanillin and 87.7 mg/g for Fe₃O₄@CS-Vanillin. Adsorption kinetics fit the pseudo-second-order model with R2 values of 0.97 and 0.95, respectively. XPS results showed that Cr(III) accounted for 66.73 % (CS-Vanillin) and 76.81 % (Fe₃O₄@CS-Vanillin), confirming Cr(VI) removal via reductive adsorption. Thermodynamic analysis revealed that CS-Vanillin exhibited a non-spontaneous, endothermic process (positive ΔG, ΔH, ΔS), while Fe₃O₄@CS-Vanillin showed a spontaneous, exothermic process (negative ΔG, ΔH, ΔS), indicating increased order during adsorption. Statistical analyses (paired t-tests, two-way ANOVA) confirmed the superior metal removal efficiency of Fe₃O₄@CS-Vanillin, with significant effects of pH, time, and temperature. Incorporation of Fe₃O₄ nanoparticles enhanced stability and surface area, making Fe₃O₄@CS-Vanillin promising for industrial applications.
