UUnderstanding the interactions of humic acid and clay minerals is important for modeling the geochemical fate and transport of nutrients and pollutants in soil and natural waters. In order to assess clay minerals “kaolinite and montmorillonite” selectivity for humic acid fractions adsorption, leonardite humic acid has been used. The sample of humic acid was fractionated by ultrafiltration into three fractions of different molecular size (F1, 300,000–50, 000; F2, 50,000–10,000; F3, 10,000–1, 000 daltons). Characterization by FT-IR and solid state 13C nuclear magnetic resonance spectroscopy (NMR) indicated that the molecules of the fraction &gt; 50,000 daltons were primarily aliphatic, while the smaller molecules of the fraction &lt; 10,000 dalton were predominantly aromatic. Novel features of adsorption of humic acid fractions onto kaolinite and montmorillonite at pH = 6 and NaCl 0.1 mol dm-3 as ionic strength were evaluated. The adsorbed and unadsorbed humic acid fractions were characterized by FT-IR, solid-state 13C nuclear magnetic resonance spectroscopy (NMR) and X-ray absorption spectroscopy (XAS) analysis. Compared studied between humic acid fractions adsorbed onto kaolinite and montmorillonite carried out to explain which fraction of humic acid "primarily aliphatic or predominantly aromatic" could be more adsorbed onto kaolinite and montmorillonite.

Assessment of clay minerals selectivity for adsorption of humic acid fraction

249th National Meeting (2015)

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