A novel sustainable CMC/XG/KAO biopolymer–clay composite hydrogel for efficient dye removal and water treatment
7 affiliations
- 1Department of Physics, Faculty of Science, University of Tabuk
- 2Chemistry Department, Faculty of Science, Beni-Suef University
- 3Department of Materials and Optoelectronic Science, National Sun Yat-Sen University
- 4Physics Department, Faculty of Science, Al-Azhar University
- 5Department of Chemistry, Faculty of Science, University of Tabuk
- 6Center of Excellence in Environmental Studies, King Abdulaziz University
- 7Laboratoire Photovoltaïque, Centre de Recherches et des Technologies de l’Énergie, Technopôle de Borj-Cédria
Abstract
A sustainable biopolymer clay composite hydrogel based on carboxymethyl cellulose (CMC), xanthan gum (XG), and kaolinite (KAO) was successfully synthesized via ionic crosslinking using Ca2⁺ ions and evaluated for the removal of anionic Orange II (OII) and cationic Malachite Green (MG) dyes from aqueous solutions. Structural and morphological analysis by SEM, XRD, FTIR, and EDX improved the formation of a porous three-dimensional hydrogel network with strong polymer–clay interactions. The FTIR bands at 912, 756, 700 and 537 cm−1 confirmed the presence of kaolinite in the hydrogel matrix. The adsorption performance was investigated as a function of adsorbent dosage, contact time, initial dye concentration, and solution pH. The hydrogel exhibited significantly higher adsorption efficiency toward MG than toward OII, which was attributed to the strong electrostatic interactions between the negatively charged functional groups (–COO⁻ and –OH) in the hydrogel matrix and the cationic dye molecules. Maximum removal efficiencies of approximately 97.15% for MG at pH 12 and 85% for OII at pH 2 were observed. Adsorption equilibrium was attained within 180 min. Isotherm studies revealed that MG adsorption followed the Langmuir model, with a maximum adsorption capacity of 90.09 mg/g, whereas OII adsorption was better explained by the Freundlich model, suggesting heterogeneous multilayer adsorption. According to the kinetic analysis, the pseudo-first-order model better explained the adsorption mechanism for both dyes. Furthermore, the hydrogel demonstrated good reusability with minimal loss in performance after five adsorption–desorption cycles. The hydrogel surface becomes negatively charged at pH values above the pHPZC (≈6.0), resulting in strong electrostatic attraction toward the cationic MG molecules. These results demonstrate the potential of the CMC/XG/KAO hydrogel as an effective, affordable, and eco-friendly adsorbent for treating wastewater contaminated with dyes.
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BibTeX
@article{rashad2026novel,
title = {{A novel sustainable CMC/XG/KAO biopolymer–clay composite hydrogel for efficient dye removal and water treatment}},
author = {M. Rashad and Omayma F. Abdel Gawad and Shams A. M. Issa and Ahmed F. M. EL-Mahdy and Hesham M. H. Zakaly and Meshari M. Aljohani and Naifa S. Alatawi and Duna A. K. Alenazi and Kholoud M. Alnahdi and Mohammad Aslam and Saloua Helali and Bandar Alatawi},
journal = {Scientific Reports},
year = {2026},
month = sep,
doi = {10.1038/s41598-026-67714-4},
url = {https://doi.org/10.1038/s41598-026-67714-4},
note = {CC BY},
}
RIS
TY - JOUR
TI - A novel sustainable CMC/XG/KAO biopolymer–clay composite hydrogel for efficient dye removal and water treatment
AU - M. Rashad
AU - Omayma F. Abdel Gawad
AU - Shams A. M. Issa
AU - Ahmed F. M. EL-Mahdy
AU - Hesham M. H. Zakaly
AU - Meshari M. Aljohani
AU - Naifa S. Alatawi
AU - Duna A. K. Alenazi
AU - Kholoud M. Alnahdi
AU - Mohammad Aslam
AU - Saloua Helali
AU - Bandar Alatawi
PY - 2026
DA - 2026/09/01
JO - Scientific Reports
DO - 10.1038/s41598-026-67714-4
UR - https://doi.org/10.1038/s41598-026-67714-4
AB - A sustainable biopolymer clay composite hydrogel based on carboxymethyl cellulose (CMC), xanthan gum (XG), and kaolinite (KAO) was successfully synthesized via ionic crosslinking using Ca2⁺ ions and evaluated for the removal of anionic Orange II (OII) and cationic Malachite Green (MG) dyes from aqueous solutions. Structural and morphological analysis by SEM, XRD, FTIR, and EDX improved the formation of a porous three-dimensional hydrogel network with strong polymer–clay interactions. The FTIR bands at 912, 756, 700 and 537 cm−1 confirmed the presence of kaolinite in the hydrogel matrix. The adsorption performance was investigated as a function of adsorbent dosage, contact time, initial dye concentration, and solution pH. The hydrogel exhibited significantly higher adsorption efficiency toward MG than toward OII, which was attributed to the strong electrostatic interactions between the negatively charged functional groups (–COO⁻ and –OH) in the hydrogel matrix and the cationic dye molecules. Maximum removal efficiencies of approximately 97.15% for MG at pH 12 and 85% for OII at pH 2 were observed. Adsorption equilibrium was attained within 180 min. Isotherm studies revealed that MG adsorption followed the Langmuir model, with a maximum adsorption capacity of 90.09 mg/g, whereas OII adsorption was better explained by the Freundlich model, suggesting heterogeneous multilayer adsorption. According to the kinetic analysis, the pseudo-first-order model better explained the adsorption mechanism for both dyes. Furthermore, the hydrogel demonstrated good reusability with minimal loss in performance after five adsorption–desorption cycles. The hydrogel surface becomes negatively charged at pH values above the pHPZC (≈6.0), resulting in strong electrostatic attraction toward the cationic MG molecules. These results demonstrate the potential of the CMC/XG/KAO hydrogel as an effective, affordable, and eco-friendly adsorbent for treating wastewater contaminated with dyes.
SN - 2045-2322
ER -