Chemical and Spectroscopic Studies on a Humic Acid Extracted from Clover Straw | ||||
| Journal of Agricultural Chemistry and Biotechnology | ||||
| Article 1, Volume 16, Issue 5, May 2025, Page 73-76 PDF (375.53 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jacb.2025.379159.1110 | ||||
 View on SCiNiTO | ||||
| Author | ||||
Nancy A. Taha 
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| Agricultural Chemistry Department, Faculty of Agriculture, Mansoura University, P.O. Box 35336, El-Mansoura, Egypt | ||||
| Abstract | ||||
| This study investigates the chemical composition and structural characteristics of humic acid (HA) extracted from clover straw using chemical and spectroscopic analyses. The extraction process involved using 0.1N NaOH under nitrogen, followed by acid precipitation, dialysis, and freeze-drying. The isolated HA was analyzed through elemental analysis, functional group quantification, Fourier-transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Elemental analysis revealed that carbon (53.9%) and oxygen (36.0%) were the main elements, with smaller amounts of hydrogen (5.2%), nitrogen (4.3%), and sulfur (0.6%). The C/N ratio (12.5) indicated a mature HA structure, while the C/H (10.4) and O/H (6.9) ratios reflected its aromaticity and oxidation levels. Functional group analysis showed high levels of carboxyl (3.82 meq/g), phenolic-OH (1.86 meq/g), and alcoholic-OH (1.83 meq/g) groups, enhancing its reactivity and complexation abilities. FTIR analysis identified major absorption bands related to hydrogen-bonded OH, aliphatic C-H, aromatic C=C, carbonyl (C=O), and polysaccharide-related C-O functional groups, confirming the presence of various oxygen-containing groups. ¹H-NMR spectra displayed signals in the ranges of 6–8.2 ppm (aromatic protons), 3–5 ppm (carbohydrate and oxygen-bound protons), and 0.8–3 ppm (aliphatic chains), indicating the presence of polymethylene chains and aromatic rings, suggesting a complex molecular structure. Overall, the study highlights the structural and functional diversity of HA derived from plant residues, with clover straw-derived HA exhibiting rich functional groups and a complex molecular structure. | ||||
| Keywords | ||||
| Humic acid; FTIR; ¹H-NMR; functional groups | ||||
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