Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite
The interaction of organic matter with mineral components of the solid phase of soils is the most important process that regulates the cycle and balance of carbon in the biosphere. The adsorption of humic acids on minerals is accompanied by their fractionation in size, composition, and amphiphilicit...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-11-01
|
| Series: | Agronomy |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4395/11/12/2420 |
| _version_ | 1827674522177765376 |
|---|---|
| author | Ksenia Kolchanova Inna Tolpeshta Yulia Izosimova |
| author_facet | Ksenia Kolchanova Inna Tolpeshta Yulia Izosimova |
| author_sort | Ksenia Kolchanova |
| collection | DOAJ |
| description | The interaction of organic matter with mineral components of the solid phase of soils is the most important process that regulates the cycle and balance of carbon in the biosphere. The adsorption of humic acids on minerals is accompanied by their fractionation in size, composition, and amphiphilicity, thus decreasing their heterogeneity. Despite a strong interest in studying the regularities and mechanisms of the interaction between natural organic matter and layered aluminosilicates, it is necessary to take into account the natural diversity of soil organic matter, adsorption conditions, and mineral composition. This study was designed to investigate the adsorption regularities of fulvic acid (FA) and water-extractable organic matter (WEOM) isolated from horizon H of peaty-podzolic-gleyic soil on kaolinite and muscovite. Sorbates and sorbents were examined by the following methods: high-pressure size exclusion chromatography (HPSEC), high-performance liquid chromatography (HPLC), and potentiometric titration. The specific surface areas of the sorbents were determined by the sorption of N<sub>2</sub> molecules. We found that hydrophobic components of FA and WEOM are mainly adsorbed on mineral surfaces. The adsorption of FA and WEOM on kaolinite and muscovite is followed by decreased hydrophobicity of organic matter and decreased heterogeneity of its amphiphilic properties in an equilibrium solution. At pH levels around 6, sorption of organic matter from FA solution containing 19% and 81% hydrophilic and hydrophobic components, respectively, onto kaolinite and muscovite occurs mainly due to hydrophobic components. Hydrophobic interactions on siloxane surfaces are the main mechanism to fix FA on both minerals. Kaolinite adsorbs slightly more organic carbon per unit area than muscovite. The adsorption of WEOM from a solution with 41% hydrophilic and 59% hydrophobic components results not only from hydrophobic and hydrophilic components but also from hydrophobic and electrostatic interactions and depends on pH. The most hydrophobic fractions of organic matter are adsorbed from the hydrophobic components on the surface of both minerals. Under conditions of the performed experiments at pH < 5, more WEOM is adsorbed on muscovite than on kaolinite. |
| first_indexed | 2024-03-10T04:40:38Z |
| format | Article |
| id | doaj.art-872cf1f0491844548e7ded6b5fbe5c33 |
| institution | Directory Open Access Journal |
| issn | 2073-4395 |
| language | English |
| last_indexed | 2024-03-10T04:40:38Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Agronomy |
| spelling | doaj.art-872cf1f0491844548e7ded6b5fbe5c332023-11-23T03:21:36ZengMDPI AGAgronomy2073-43952021-11-011112242010.3390/agronomy11122420Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and MuscoviteKsenia Kolchanova0Inna Tolpeshta1Yulia Izosimova2Soil Science Faculty, Lomonosov Moscow State University, GSP-1, 1-12 Leninskie Gory, 119991 Moscow, RussiaSoil Science Faculty, Lomonosov Moscow State University, GSP-1, 1-12 Leninskie Gory, 119991 Moscow, RussiaSoil Science Faculty, Lomonosov Moscow State University, GSP-1, 1-12 Leninskie Gory, 119991 Moscow, RussiaThe interaction of organic matter with mineral components of the solid phase of soils is the most important process that regulates the cycle and balance of carbon in the biosphere. The adsorption of humic acids on minerals is accompanied by their fractionation in size, composition, and amphiphilicity, thus decreasing their heterogeneity. Despite a strong interest in studying the regularities and mechanisms of the interaction between natural organic matter and layered aluminosilicates, it is necessary to take into account the natural diversity of soil organic matter, adsorption conditions, and mineral composition. This study was designed to investigate the adsorption regularities of fulvic acid (FA) and water-extractable organic matter (WEOM) isolated from horizon H of peaty-podzolic-gleyic soil on kaolinite and muscovite. Sorbates and sorbents were examined by the following methods: high-pressure size exclusion chromatography (HPSEC), high-performance liquid chromatography (HPLC), and potentiometric titration. The specific surface areas of the sorbents were determined by the sorption of N<sub>2</sub> molecules. We found that hydrophobic components of FA and WEOM are mainly adsorbed on mineral surfaces. The adsorption of FA and WEOM on kaolinite and muscovite is followed by decreased hydrophobicity of organic matter and decreased heterogeneity of its amphiphilic properties in an equilibrium solution. At pH levels around 6, sorption of organic matter from FA solution containing 19% and 81% hydrophilic and hydrophobic components, respectively, onto kaolinite and muscovite occurs mainly due to hydrophobic components. Hydrophobic interactions on siloxane surfaces are the main mechanism to fix FA on both minerals. Kaolinite adsorbs slightly more organic carbon per unit area than muscovite. The adsorption of WEOM from a solution with 41% hydrophilic and 59% hydrophobic components results not only from hydrophobic and hydrophilic components but also from hydrophobic and electrostatic interactions and depends on pH. The most hydrophobic fractions of organic matter are adsorbed from the hydrophobic components on the surface of both minerals. Under conditions of the performed experiments at pH < 5, more WEOM is adsorbed on muscovite than on kaolinite.https://www.mdpi.com/2073-4395/11/12/2420fulvic acidsclay mineralsadsorptionamphiphilicity |
| spellingShingle | Ksenia Kolchanova Inna Tolpeshta Yulia Izosimova Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite Agronomy fulvic acids clay minerals adsorption amphiphilicity |
| title | Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite |
| title_full | Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite |
| title_fullStr | Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite |
| title_full_unstemmed | Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite |
| title_short | Adsorption of Fulvic Acid and Water Extractable Soil Organic Matter on Kaolinite and Muscovite |
| title_sort | adsorption of fulvic acid and water extractable soil organic matter on kaolinite and muscovite |
| topic | fulvic acids clay minerals adsorption amphiphilicity |
| url | https://www.mdpi.com/2073-4395/11/12/2420 |
| work_keys_str_mv | AT kseniakolchanova adsorptionoffulvicacidandwaterextractablesoilorganicmatteronkaoliniteandmuscovite AT innatolpeshta adsorptionoffulvicacidandwaterextractablesoilorganicmatteronkaoliniteandmuscovite AT yuliaizosimova adsorptionoffulvicacidandwaterextractablesoilorganicmatteronkaoliniteandmuscovite |