Journal of Soils and Sediments

, Volume 16, Issue 7, pp 1841–1848 | Cite as

Investigation of sorbate-induced plasticization of Pahokee peat by solid-state NMR spectroscopy

  • Xiaoyan Cao
  • Charisma Lattao
  • Klaus Schmidt-Rohr
  • Jingdong MaoEmail author
  • Joseph J. PignatelloEmail author
Soils, Sec 1 • Soil Organic Matter Dynamics and Nutrient Cycling • Research Article



Sorbate-induced swelling and plasticization of sorbent have been linked to sorption hysteresis of organic compounds in the natural organic matter of isolated humic acids, soils, and coals. The above processes, which have important implications for the fate and bioavailability of organic and inorganic contaminants, are mostly based on macroscopic changes and require molecular-level confirmation. This study aimed to investigate the presence or absence of sorbate-induced plasticization of Pahokee peat soil as a function of different sorbates.

Materials and methods

The plasticization of Pahokee peat soil was studied upon sorption of different proton-free solutes including C6D6, CDCl3, CCl4, C2Cl4, CBr4, C6D5Cl, and C5D5N, covering apolar and polar aromatic and aliphatic compounds. The swelling and plasticization of Pahokee peat soil were verified at the molecular level by 1H wideline and two-dimensional wideline separation (2D WISE) NMR. The use of 1H wideline shapes is the traditional technique for studying molecular dynamics but hampered by the lack of spectral resolution, with one dimension displaying 13C chemical shifts and the second showing 1H wideline shapes, is capable of providing information on molecular dynamics of specific functional groups.

Results and discussion

Our results showed that the segments of Pahokee peat soil sorbed with C6D6, C2Cl4, and C5D5N became more mobile, but the changes due to the plasticization were small. Both C6D6 and C5D5N selectively increased the mobility of specific components, C6D6 of the nonpolar alkyl domains, and C5D5N of both the nonpolar alkyl domains and aromatic components.


Some liquid solutes at high concentrations (2–5 wt%) are capable of slightly “softening” natural organic matter of a soil, and this provides support for the hypothesis that natural organic matter in Pahokee peat soil is in a glassy state that is subject to plasticization.


1H wideline Soil organic matter Glassy state Swelling Wideline separation 



This research was supported by grants from the National Science Foundation (CBET 0853682 and 0853950 and EAR 1226323).


  1. Akhter M, Chughtai A, Smith D (1985) The structure of hexane soot I: spectroscopic studies. Appl Spectrosc 39:143–153CrossRefGoogle Scholar
  2. Braida WJ, Pignatello JJ, Lu YF, Ravikovitch PI, Neimark AV, Xing BS (2003) Sorption hysteresis of benzene in charcoal particles. Environ Sci Technol 37:409–417CrossRefGoogle Scholar
  3. Cao X, Lattao C, Pignatello JJ, Mao J, Schmidt-Rohr K (2014) Sorption selectivity in natural organic matter probed with fully deuterium-exchanged and carbonyl-13C-labeled benzophenone and 1H-13C NMR spectroscopy. Environ Sci Technol 48:8645–8652CrossRefGoogle Scholar
  4. Chen Q, Schmidt-Rohr K (2006) Measurement of the local 1H spin-diffusion coefficient in polymers. Solid State Nucl Magn Reson 29:142–152CrossRefGoogle Scholar
  5. Chen Q, Hou S, Schmidt-Rohr K (2004) A simple scheme for probehead background suppression in one-pulse 1H NMR. Solid State Nucl Magn Reson 26:11–15CrossRefGoogle Scholar
  6. DeLapp RC, LeBoeuf EJ (2004) Thermal analysis of whole soils and sediment. J Environ Qual 33:330–337CrossRefGoogle Scholar
  7. Graber E, Borisover M (1998) Hydration-facilitated sorption of specifically interacting organic compounds by model soil organic matter. Environ Sci Technol 32:258–263CrossRefGoogle Scholar
  8. Jäger A, Schaumann GE, Bertmer M (2011) Optimized NMR spectroscopic strategy to characterize water dynamics in soil samples. Org Geochem 42:917–925CrossRefGoogle Scholar
  9. Jonker MT, Koelmans AA (2002) Extraction of polycyclic aromatic hydrocarbons from soot and sediment: solvent evaluation and implications for sorption mechanism. Environ Sci Technol 36:4107–4113CrossRefGoogle Scholar
  10. Kadla J, Kubo S, Gilbert R, Venditti R (2002) Lignin-based carbon fibers. In: Hu TQ (ed) Chemical modification, properties, and usage of lignin. Springer, US, pp 121–137CrossRefGoogle Scholar
  11. Karapanagioti HK, Childs J, Sabatini DA (2001) Impacts of heterogeneous organic matter on phenanthrene sorption: different soil and sediment samples. Environ Sci Technol 35:4684–4690CrossRefGoogle Scholar
  12. Leboeuf EJ, Weber WJ (1997) A distributed reactivity model for sorption by soils and sediments.8. Sorbent organic domains: discovery of a humic acid glass transition and an argument for a polymer-based model. Environ Sci Technol 31:1697–1702CrossRefGoogle Scholar
  13. LeBoeuf EJ, Weber WJ (2000a) Macromolecular characteristics of natural organic matter. 2. Sorption and desorption behavior. Environ Sci Technol 34:3632–3640CrossRefGoogle Scholar
  14. LeBoeuf EJ, Weber WJ Jr (2000b) Macromolecular characteristics of natural organic matter. 1. Insights from glass transition and enthalpic relaxation behavior. Environ Sci Technol 34:3623–3631CrossRefGoogle Scholar
  15. LeBoeuf EJ, Zhang L (2005) Thermal analytical study of carbonaceous and humic-based soil/sediment organic matter. In: The ASA-CSSA-SSSA International Annual Meetings. UT, Salt Lake CityGoogle Scholar
  16. Li L, Zhao ZY, Huang WL, Peng P, Sheng GY, Fu JM (2004) Characterization of humic acids fractionated by ultrafiltration. Org Geochem 35:1025–1037CrossRefGoogle Scholar
  17. Lu YF, Pignatello JJ (2002) Demonstration of the “conditioning effect” in soil organic matter in support of a pore deformation mechanism for sorption hysteresis. Environ Sci Technol 36:4553–4561CrossRefGoogle Scholar
  18. Lu YF, Pignatello JJ (2004a) History-dependent sorption in humic acids and a lignite in the context of a polymer model for natural organic matter. Environ Sci Technol 38:5853–5862CrossRefGoogle Scholar
  19. Lu YF, Pignatello JJ (2004b) Sorption of apolar aromatic compounds to soil humic acid particles affected by aluminum(III) ion cross-linking. J Environ Qual 33:1314–1321CrossRefGoogle Scholar
  20. Lyon WG (1995) Swelling of peats in liquid methyl, tetramethylene and propyl sulfoxides and in liquid propyl sulfone. Environ Toxicol Chem 14:229–236CrossRefGoogle Scholar
  21. Mao JD, Schmidt-Rohr K (2006) Absence of mobile carbohydrate domains in dry humic substances proven by NMR, and implications for organic-contaminant sorption models. Environ Sci Technol 40:1751–1756CrossRefGoogle Scholar
  22. Mao J-D, Hundal L, Thompson M, Schmidt-Rohr K (2002a) Correlation of poly (methylene)-rich amorphous aliphatic domains in humic substances with sorption of a nonpolar organic contaminant, phenanthrene. Environ Sci Technol 36:929–936CrossRefGoogle Scholar
  23. Mao J, Ding G, Xing B (2002b) Domain mobility of humic acids investigated with one-and two-dimensional nuclear magnetic resonance: support for dual-mode sorption model. Commun Soil Sci Plant Anal 33:1679–1688CrossRefGoogle Scholar
  24. McKenna GB (1989) 10—glass formation and glassy behavior. In: Bevington GAC (ed) Comprehensive polymer science and supplements. Pergamon, Amsterdam, pp 311–362CrossRefGoogle Scholar
  25. Pignatello JJ (2012) Dynamic interactions of natural organic matter and organic compounds. J Soils Sediments 12:1241–1256CrossRefGoogle Scholar
  26. Pignatello JJ, Lu Y, LeBoeuf EJ, Huang W, Song J, Xing B (2006) Nonlinear and competitive sorption of apolar compounds in black carbon-free natural organic materials. J Environ Qual 35:1049–1059CrossRefGoogle Scholar
  27. Razouk R, Saleeb F, Said F (1968) The heat of wetting and immersional swelling of charcoal. J Colloid Interface Sci 28:487–492CrossRefGoogle Scholar
  28. Rodriguez F (1996) Principles of polymer systems, 4th edn. Taylor & Francis, Washington, DCGoogle Scholar
  29. Sander M, Pignatello JJ (2005a) Characterization of charcoal adsorption sites for aromatic compounds: insights drawn from single-solute and Bi-solute competitive experiments. Environ Sci Technol 39:1606–1615CrossRefGoogle Scholar
  30. Sander M, Pignatello JJ (2005b) An isotope exchange technique to assess mechanisms of sorption hysteresis applied to naphthalene in kerogenous organic matter. Environ Sci Technol 39:7476–7484CrossRefGoogle Scholar
  31. Sander M, Pignatello JJ (2007) On the reversibility of sorption to black carbon: distinguishing true hysteresis from artificial hysteresis caused by dilution of a competing adsorbate. Environ Sci Technol 41:843–849CrossRefGoogle Scholar
  32. Sander M, Lu YF, Pignatello JJ (2005) A thermodynamically based method to quantify true sorption hysteresis. J Environ Qual 34:1063–1072CrossRefGoogle Scholar
  33. Sander M, Lu YF, Pignatello JJ (2006) Conditioning-annealing studies of natural organic matter solids linking irreversible sorption to irreversible structural expansion. Environ Sci Technol 40:170–178CrossRefGoogle Scholar
  34. Schaumann GE, Antelmann O (2000) Thermal characteristics of soil organic matter measured by DSC: a hint on a glass transition. J Plant Nutr Soil Sci 163:179–181CrossRefGoogle Scholar
  35. Schaumann G, Bertmer M (2008) Do water molecules bridge soil organic matter molecule segments? Eur J Soil Sci 59:423–429CrossRefGoogle Scholar
  36. Schaumann GE, Leboeuf EJ (2005) Glass transitions in peat: their relevance and the impact of water. Environ Sci Technol 39:800–806CrossRefGoogle Scholar
  37. Schmidt-Rohr K, Spiess HW (1994) Multidimensional solid-state NMR and polymers. Academic Press, New YorkGoogle Scholar
  38. Schmidt-Rohr K, Clauss J, Spiess H (1992) Correlation of structure, mobility, and morphological information in heterogeneous polymer materials by two-dimensional wideline-separation NMR spectroscopy. Macromolecules 25:3273–3277CrossRefGoogle Scholar
  39. Schwarzenbach RP, Gschwend PM, Imboden DM (2003) Organic liquid–water partitioning. In: Environmental Organic Chemistry. Wiley, Hoboken, New Jersey, pp 213–244Google Scholar
  40. Smernik RJ, Kookana RS, Skjemstad JO (2006) NMR characterization of 13C-benzene sorbed to natural and prepared charcoals. Environ Sci Technol 40:1764–1769CrossRefGoogle Scholar
  41. Tekely P, Palmas P, Mutzenhardt P (1993) Elimination of heteronuclear dipolar interactions from carbon-13-detected proton spectra in wideline-separation nuclear magnetic resonance spectroscopy. Macromolecules 26:7363–7365CrossRefGoogle Scholar
  42. Thirtha V, Lehman R, Nosker T (2005) Glass transition phenomena in melt-processed polystyrene/polypropylene blends. Polym Eng Sci 45:1187–1193CrossRefGoogle Scholar
  43. Thorn KA, Cox LG (2009) N-15 NMR spectra of naturally abundant nitrogen in soil and aquatic natural organic matter samples of the International Humic Substances Society. Org Geochem 40:484–499CrossRefGoogle Scholar
  44. Xia GS, Pignatello JJ (2001) Detailed sorption isotherms of polar and apolar compounds in a high-organic soil. Environ Sci Technol 35:84–94CrossRefGoogle Scholar
  45. Xing B, Pignatello JJ (1997) Dual-mode sorption of low-polarity compounds in glassy poly (vinyl chloride) and soil organic matter. Environ Sci Technol 31:792–799CrossRefGoogle Scholar
  46. Xiong JC, Maciel GE (2002) Interactions between pyridine and coal at the molecular level: insights from variable-temperature 1H NMR studies of pyridine-saturated coal. Energy Fuels 16:497–509CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Chemistry and BiochemistryOld Dominion UniversityNorfolkUSA
  2. 2.Department of Environmental SciencesThe Connecticut Agricultural Experiment StationNew HavenUSA
  3. 3.Department of ChemistryBrandeis UniversityWalthamUSA

Personalised recommendations