| Fe-Modified Chitosan/Graphene Oxide for Glyphosate Removal and Preconcentration from Water |
| کد مقاله : 1461-IWWA |
| نویسندگان |
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سیامک زواره *1، فاطمه زارع ریحانی2 1عضو هیئت علمی 2دانشجو |
| چکیده مقاله |
| Glyphosate residues in water require treatment methods that can both remove the herbicide and improve its determination at low concentrations. In this study, chitosan/graphene oxide (CS/GO) and its Fe- and Cu-modified forms were prepared and evaluated for glyphosate adsorption and preconcentration from aqueous solutions. The materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Metal modification produced rougher, more heterogeneous surfaces and confirmed metal-associated sites in the CS/GO framework. Glyphosate was monitored by UV spectrophotometry at 277 nm. The direct calibration was linear over 5-25 mg L⁻¹ (R² = 0.975), and the LOD and LOQ were 0.45 and 1.35 mg L⁻¹, respectively. Adsorption capacity increased in the order CS/GO < Cu-CS/GO < Fe-CS/GO. The Langmuir maximum capacities were 14.54, 33.98, and 39.82 mg g⁻¹, respectively, while the Freundlich model gave the best fit for all three adsorbents. For Fe-CS/GO, equilibrium was reached in about 60 min and the pseudo-second-order model gave the best kinetic fit. Using 300 mg Fe-CS/GO with 150 mL sample and desorption into 5 mL mild alkaline water gave 95.4% recovery and a practical enrichment factor of 28.62. The estimated post-preconcentration LOD and LOQ were 0.016 and 0.047 mg L⁻¹, showing the potential of Fe-CS/GO for combined glyphosate removal and enrichment before UV determination. |
| کلیدواژه ها |
| Glyphosate, Adsorption, Chitosan, Graphene oxide, Preconcentration, Water |
| وضعیت: پذیرفته شده برای ارائه شفاهی |
