Efficient and Reusable PEDMT Microbeads for Azo Dye Removal: Congo Red Adsorption from Aqueous Media
CHEMISTRYSELECT, vol.10, no.44, 2025 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 10 Issue: 44
- Publication Date: 2025
- Doi Number: 10.1002/slct.202504268
- Journal Name: CHEMISTRYSELECT
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core
- Bursa Uludag University Affiliated: Yes
Abstract
The removal of persistent dyes from aqueous environments is a critical concern due to their ecological toxicity and resistance to degradation. In this study, poly(ethylene glycol dimethacrylate-N-methacryloyl-amido-L-tryptophan methyl ester) [PEDMT] microbeads were synthesized via suspension polymerization and utilized as efficient adsorbents for the removal of Congo Red (CR), a emodel anionic azo dye. The microbeads exhibited a high specific surface area of 1103 m(2)/g and a porous morphology favorable for adsorption. Batch adsorption experiments were conducted to investigate the effects of pH, contact time, adsorbent dosage, dye concentration, and temperature on adsorption performance. Batch adsorption studies showed a maximum adsorption capacity of 86.32 +/- 3.63 mg/g at 277 K, 75.69 +/- 2.51 mg/g at 298 K, and 73.64 +/- 4.34 mg/g at 308 K at pH 6.0. Kinetic data fitted best to the pseudo-second-order model, with an activation energy of 25.24 kJ/mol. Equilibrium data were well described by both Langmuir and Freundlich isotherm models, suggesting a mixed adsorption mechanism. Thermodynamic parameters confirmed that the adsorption process was spontaneous (Delta G degrees = -7.15 to -7.76 kJ/mol) and exothermic (Delta H degrees = -1.78 kJ/mol). Consequently, the PEDMT microbeads has an application potential as reusable adsorbents for the treatment of azo dye-contaminated waters.