Synergistic synthesis: Optimizing natural alginate/carrageenan polysaccharides crosslinked with polyacrylic acid for enhanced rhodamine B removal in aqueous environments | ||
| Egyptian Journal of Chemistry | ||
| Articles in Press, Accepted Manuscript, Available Online from 11 November 2025 | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejchem.2025.425544.12362 | ||
| Authors | ||
| Chiraz Ammar1; Ghadah A Alharbi2; Yassine El-Ghoul* 3 | ||
| 1Department of Fashion Design, College of Arts and Design, Qassim University, Buraidah 51452, Saudi Arabia | ||
| 2Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi Arabia | ||
| 3Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Qassim, Saudi Arabia | ||
| Abstract | ||
| The discharge of synthetic dyes into aquatic systems poses a persistent environmental and health threat due to their stability, toxicity, and resistance to biodegradation. Rhodamine B dye (RhB), a widely used cationic dye, is particularly problematic and demands effective remediation strategies. In this work, a novel crosslinked ternary composite adsorbent based on alginate, poly(acrylic acid), and λ-carrageenan (poly-AG/PAA/λ-CAR) was synthesized and evaluated for RhB removal. The composite structure and morphology were confirmed by Fourier-transform infrared spectroscopy (FTIR), swelling studies, and scanning electron microscopy (SEM). Batch adsorption experiments demonstrated that removal efficiency was strongly influenced by pH, initial concentration, contact time, and adsorbent dosage. Optimal RhB removal occurred at pH 8, reaching equilibrium within 60 min. Adsorption followed the PSO model (R² > 0.99), indicating chemisorption. The Langmuir model fitted best, with a maximum capacity of 1111.1 mg g⁻¹ (R² = 0.99), while the Freundlich model suggested multilayer adsorption on a heterogeneous surface. The Temkin isotherm further highlighted robust adsorbate, adsorbent interactions, with a binding energy of 42.51 kJ mol⁻¹. The outstanding performance of the poly-AG/PAA/λ-CAR composite is attributed to the synergistic contributions of alginate’s carboxyl groups, λ-carrageenan’s sulfate functionalities, and the structural resilience of poly(acrylic acid). These findings establish poly-AG/PAA/λ-CAR as a sustainable, efficient, and reusable adsorbent for cationic dye removal, offering a promising alternative for the treatment of industrial wastewater. | ||
| Keywords | ||
| Polymer; alginate; carrageenan; SEM; adsorption; isotherms; dye environmental application | ||
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