Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 12 3 2026 07 01 Adsorption of hexavalent chromium from aqueous solution using glucose-derived spherical activated carbon: The role of functional groups 308 326 1673 10.22104/aet.2026.7860.2207 EN Nguyen Duy Dat Faculty of Chemical and Food Technology, Ho Chi Minh City University of Technology and Engineering, Viet Nam Sang Quang Huynh Faculty of Chemical and Food Technology, Ho Chi Minh City University of Technology and Engineering, Viet Nam Linh My Nguyen Faculty of Chemical and Food Technology, Ho Chi Minh City University of Technology and Engineering, Viet Nam Hai Nguyen Tran Institute of Fundamental and Applied Sciences, Duy Tan University, Ho Chi Minh City 70000, Viet Nam Journal Article 2025 09 23 This research explores the production of spherical activated carbon derived from glucose using the combination of a hydrothermal process followed by chemical impregnation with hydrogen peroxide (H₂O₂), citric acid (CA), and acrylic acid (AA), and pyrolysis. The adsorption performances, kinetics, and thermodynamics of the synthesized materials were compared with those of the material without chemical impregnation using batch experiments. Boehm titration and Fourier-transform infrared spectroscopy (FTIR) confirmed an increase in oxygen-containing functional groups (carboxyl, lactone, and phenol), facilitating adsorption through electrostatic interaction, reduction, and complexation. Adsorption kinetics and isotherm modeling confirmed that the process adhered to the Elovich model and the Redlich-Peterson or Langmuir isotherm, suggesting chemisorption dominance. Among the materials tested, AA-modified activated carbon (AC-AA) exhibited the highest adsorption capacity of 244 mg/g, outperforming previously studied biochar-based adsorbents. Kinetic and thermodynamic assessments demonstrated that Cr(VI) adsorption was spontaneous (ΔG<0), endothermic (ΔH>0), and entropy-favored (ΔS>0). Notably, the study elucidates the concurrent adsorption and reduction of Cr(VI) to Cr(III) at low pH, driven by electron transfer from surface functional groups. Moreover, NaOH was identified as the most effective desorption agent, underscoring the potential for material regeneration and reuse. This research highlights the potential application of glucose-based carbon spheres with functionalized surfaces as a sustainable, cost-effective solution for Cr(VI) removal in industrial wastewater treatment. https://aet.irost.ir/article_1673_81cda9ab41fc0f093beeeba5d74bf1ad.pdf