pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties
Preferential adsorption occurs during interaction between humic substances (HS) and metal (hydr)oxides, however, the preferential adsorption and thermal stability mechanism remains poorly understood. Here we show that solution pH can modify the configuration of humic acid (HA) and fulvic acid (FA),...
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Elsevier
2025-02-01
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| Series: | Ecotoxicology and Environmental Safety |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0147651325001745 |
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| author | Long Wang Yanan Ren Mengke Jia Jinkang Yang Hongen Liu Peng Zhao Jihua Tang Jie Ma Liping Weng Yongtao Li |
| author_facet | Long Wang Yanan Ren Mengke Jia Jinkang Yang Hongen Liu Peng Zhao Jihua Tang Jie Ma Liping Weng Yongtao Li |
| author_sort | Long Wang |
| collection | DOAJ |
| description | Preferential adsorption occurs during interaction between humic substances (HS) and metal (hydr)oxides, however, the preferential adsorption and thermal stability mechanism remains poorly understood. Here we show that solution pH can modify the configuration of humic acid (HA) and fulvic acid (FA), and thereby altering their fractionation and thermal stability in relation to goethite. At pH 5–7, particles with a molar mass of 3.5–15 kDa were preferentially adsorbed for both fulvic acid (FA) and humic acid (HA). These particles enriched in aromatic moieties and carboxylic groups (-COOH), which enhanced the stability of HS by facilitating the formation of inner-sphere complexes. Conversely, at pH levels exceeding 9.2, large particles (> 50 kDa) and those rich in aliphatic moieties were preferentially adsorbed for both HA and FA, attributed to the increased significance of hydrophobic interactions. However, this stabilization effect on HS was limited under these conditions. FA particles exhibit a lower degree of chemical heterogeneity compared to HA particles. For FA, the variations in aromatic structures (-COOH) and aliphatic moieties were coupled, following a consistent trend in preferential adsorption as pH changed. In contrast, HA demonstrated an opposite pH dependency, with aromatic (-COOH) and aliphatic moieties displaying divergent patterns of preferential adsorption. These innovative discoveries clarify the behavior of organic matter in various environmental conditions and its interactions with minerals surfaces, thereby establishing a critical theoretical foundation for understanding the sequestration of soil organic carbon, emphasizing the dual roles of aromatic and aliphatic moieties in the preferential adsorption and stability of humic substances on goethite. |
| format | Article |
| id | doaj-art-2f2fd017c1964dc5a9046436497b792e |
| institution | Kabale University |
| issn | 0147-6513 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Elsevier |
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| series | Ecotoxicology and Environmental Safety |
| spelling | doaj-art-2f2fd017c1964dc5a9046436497b792e2025-02-07T04:46:36ZengElsevierEcotoxicology and Environmental Safety0147-65132025-02-01291117838pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moietiesLong Wang0Yanan Ren1Mengke Jia2Jinkang Yang3Hongen Liu4Peng Zhao5Jihua Tang6Jie Ma7Liping Weng8Yongtao Li9College of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, China; Postdoctoral Mobile Station of Crop Science, Henan Agricultural University, Zhengzhou 450000, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; Correspondence to: College of Resources and Environmental Sciences, Henan Agricultural University, Zhengzhou 450002, China.College of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, ChinaCollege of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, ChinaCollege of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, ChinaCollege of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, ChinaCollege of Resources and Environment, Henan Agricultural University, Zhengzhou 450000, ChinaPostdoctoral Mobile Station of Crop Science, Henan Agricultural University, Zhengzhou 450000, ChinaAgro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, ChinaAgro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China; Corresponding author.College of Natural Resources & Environment, South China Agricultural University, Guangzhou 510642, ChinaPreferential adsorption occurs during interaction between humic substances (HS) and metal (hydr)oxides, however, the preferential adsorption and thermal stability mechanism remains poorly understood. Here we show that solution pH can modify the configuration of humic acid (HA) and fulvic acid (FA), and thereby altering their fractionation and thermal stability in relation to goethite. At pH 5–7, particles with a molar mass of 3.5–15 kDa were preferentially adsorbed for both fulvic acid (FA) and humic acid (HA). These particles enriched in aromatic moieties and carboxylic groups (-COOH), which enhanced the stability of HS by facilitating the formation of inner-sphere complexes. Conversely, at pH levels exceeding 9.2, large particles (> 50 kDa) and those rich in aliphatic moieties were preferentially adsorbed for both HA and FA, attributed to the increased significance of hydrophobic interactions. However, this stabilization effect on HS was limited under these conditions. FA particles exhibit a lower degree of chemical heterogeneity compared to HA particles. For FA, the variations in aromatic structures (-COOH) and aliphatic moieties were coupled, following a consistent trend in preferential adsorption as pH changed. In contrast, HA demonstrated an opposite pH dependency, with aromatic (-COOH) and aliphatic moieties displaying divergent patterns of preferential adsorption. These innovative discoveries clarify the behavior of organic matter in various environmental conditions and its interactions with minerals surfaces, thereby establishing a critical theoretical foundation for understanding the sequestration of soil organic carbon, emphasizing the dual roles of aromatic and aliphatic moieties in the preferential adsorption and stability of humic substances on goethite.http://www.sciencedirect.com/science/article/pii/S0147651325001745Humic substancesAromatic moietiesAliphatic moietiesPreferential adsorptionThermal stabilityIron (hydr)oxide |
| spellingShingle | Long Wang Yanan Ren Mengke Jia Jinkang Yang Hongen Liu Peng Zhao Jihua Tang Jie Ma Liping Weng Yongtao Li pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties Ecotoxicology and Environmental Safety Humic substances Aromatic moieties Aliphatic moieties Preferential adsorption Thermal stability Iron (hydr)oxide |
| title | pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties |
| title_full | pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties |
| title_fullStr | pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties |
| title_full_unstemmed | pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties |
| title_short | pH-Dependent preferential adsorption and stability of humic substances on goethite: The dual role of aromatic and aliphatic moieties |
| title_sort | ph dependent preferential adsorption and stability of humic substances on goethite the dual role of aromatic and aliphatic moieties |
| topic | Humic substances Aromatic moieties Aliphatic moieties Preferential adsorption Thermal stability Iron (hydr)oxide |
| url | http://www.sciencedirect.com/science/article/pii/S0147651325001745 |
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