Influence of Solution Composition on the Ezfoliation of Organic Matter from a Model Soil System
It has recently been demonstrated that small perturbation of hydrophobic interactions and hydrogen bonding via small changes in solution composition can greatly alter the conformation of dissolved organic matter. This work investigates if the same holds for in-situ soil organic matter (SOM) by exfoliating it with solvent systems (SSs) of different compositions. The effects of aqueous solutions composed of 4.6 ×10-3 mol·L-1 acetiC acid (AA), acetonitrile (ACN), dimethyl sulfoxide (DMSO), hydrochloric acid (HCl), and methanol (MeOH) as well as 18 MΩH2O were investigated. Only the ACN SS showed marked difference in the amount and type of organic matter exfoliated compared to that exfoliated by H2O only, as monitored by UV/Vis absorbance, fluorescence, attenuated total reflectance Fourier transformed infrared (ATR-FTIR), and 13C cross polarization magic angle spinning (CP-MAS) spectroscopy. It was found that after 20 days the ACN exfoliation solution had turned brown while the other solutions remained yellow, and that this color change could be attributed to more of the humified materials being exfoliated. It was also found that an additional 25 days allowed for a larger amount of the less humified material to be subsequently exfoliated. Based on these findings, a solvation model is put forward along with an explanation for the differences seen for the ACN SS. Both are relevant to hydrophobic organic compound sorption, remediation, and soil wetting processes.
Soil organic matter Ezfoliation Synchronous fluorescence Humification indez CP-MAS 13C Wetting
Charisma Lattao Robert L.Cook
Department of Chemistry,Louisiana State University,Baton Rouge,LA,70803 Department of Chemistry,Louisiana State University,Baton Rouge,LA,70803 Department of Chemistry,Sout
国际会议
杭州
英文
298-300
2009-10-10（万方平台首次上网日期，不代表论文的发表时间）