Sorption of HOC in soils with carbonaceous contamination: Influence of organic‐matter composition

Abstract

PNSS P162/2BSummaryÐZusammenfassung Detailed information about structure and composition of organic sorbents is required to understand their impact on sorption capacity and sorption kinetic of organic pollutants. Therefore, the chemical composition of organic material from 18 geosorbents was investigated by solid-state 13 C nuclearmagnetic-resonance (NMR) spectroscopy. Structural parameters such as aromaticity, polarity, and alkyl-C content were related to the Freundlich sorption exponent (1/n) and the sorption coefficient K OC . The geosorbents included three natural and four combusted coals (carbonaceous material), three Histosols, five mineral soils from Germany containing inputs of technogenic carbonaceous material, derived from industrial activities, and four non-contaminated mineral soils from Germany. Equilibrium sorption was measured for five hydrophobic organic compounds and analyzed with the solubility-normalized Freundlich sorption isotherm. With increasing maturation degree, the proportion of polar constituents decreases from the natural soils to the coals. In contrast to the non-polluted mineral soils, the soils with technogenic input are characterized by high aromaticity and low polarity. A positive correlation between sorption coefficient K OC and aromaticity was found. The Freundlich exponent (1/n) is negatively correlated with the aromaticity, denoting an increase of adsorption processes with increasing aromaticity. Likewise, the contribution of partitioning decreases. This sorption mechanism predominates only if the organic matter in the samples contains a high proportion of polar compounds.

Black Carbon and Thermally Altered (Pyrogenic) Organic Matter: Chemical Characteristics and the Role in the Environment

“…After increasing the temperature to 900 ° C and 1000 ° C, the use of the CP technique was completely unsuccessful. Comparably, no CPMAS 13 C NMR signal was obtainable from lignite coke (Abelmann et al, 2005 ). Therefore, soils containing such material will not yield quantifi able data, and the more timeconsuming BD technique has to be applied.…”

The effect of minerals changing the sorption on non-ionic compound sorption by capacity of soil organic matter

“…Many studies have shown that the aliphatic group of organic matter is responsible for the sorption properties of non-ionic pollutants (Chefetz et al, 2000;Salloum et al, 2002;Chen et al, 2007). Conversely, several others have suggested that the key role is played by aromatic domains (Mao et al, 2002;Abelmann et al, 2005;Golding et al, 2005;Lixia et al, 2011).…”

Contaminated Urban Soils

“…11 Carbon content, polarity, aromaticity and sorption coefficient K OC for phenanthrene (Polycyclic Aromatic Hydrocarbon) of different substrates and topsoils (Data fromAbelmann et al 2005) …”