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Document Type

Original Article

Subject Areas



Humic acids; VCF


IR spectra of humic acids ( HAs) extracted by NaOH solution under different conditions showed that HAs extracted by 0.1 M after 6h and 16 h have identical finger print regions. These spectra indicate the presence of highest number of functional groups and highest aromatic COOH group content, in comparison with ( HAs) extracted by 0.1M after 2h and 24 h. IR spectrum of humic acids HAs extracted by 0.2M after 2h was generally similar with the two latter spectra. The IR spectra of HAs extracted after 2h by 0.5M, 1M, and 2M not only show the disappearance of aromatic COOH bands but also indicate the hydrolysis of ester moieties and increase the OH groups content of the extracted HAs. The IR spectra of HAs extracted at the latter three concentrations showed attacked finger print regions. Uv-Vis spectra show two clearly observable peaks at 208 and 280 nm which are characteristic to these humic acids. The spectral change of the latter are in agreement with the results obtained by IR analysis According to results obtained, the extraction by 0.1M NaOH after 16h leads to production of HAs of highest condensation, highest functional group content.

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