The influence of the rigidity of geosorbent organic matter on non-ideal sorption behaviors of chlorinated benzenes

• Published in: Water research (Oxford) Vol. 39; no. 12; pp. 2599 - 2610
• Main Authors: Ju, Daeyoung, Young, Thomas M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2005; Elsevier Science
• Subjects: Adsorption; analysis; Applied sciences; benzene; Biological and medical sciences; Biotechnology; carbon; Carbon - chemistry; chemistry; chlorinated hydrocarbons; Chlorobenzenes; Chlorobenzenes - chemistry; Environment and pollution; Equilibrium; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Geologic Sediments; Geologic Sediments - chemistry; Hard carbon; hydrophobic organic compounds; Industrial applications and implications. Economical aspects; Isotherm model; natural organic matter; Non-linear sorption; Organic Chemicals; Organic Chemicals - chemistry; organic matter; Other industrial wastes. Sewage sludge; Pollution; Solubility; Soot carbon; sorbates; sorption; sorption isotherms; Thermodynamics; Wastes; Water Pollutants, Chemical; Water Pollutants, Chemical - analysis; Water treatment and pollution; Soot carbon; Hard carbon; Isotherm model; Non-linear sorption; Equilibrium; Organic matter; Pollutant behavior; Soot; Adsorption isotherm; Prediction; Environmental factor; Modeling; Sorption; Correlation analysis; Aerosols; Air pollution; Oxidation; Phase partition; Sorbent
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2005.04.058

This study focused on evaluating the influence of the rigidity of natural organic matter (NOM) associated with four natural geosorbents in controlling the non-ideal sorption behaviors of five chlorinated benzenes. Single solute sorption isotherms for each sorbate/sorbent combination were modeled and interpreted by the Freundlich sorption isotherm and the adsorption-partitioning model based on Polanyi–Manes theory (PM model). “Rigid” organic matter was operationally quantified as the fraction of carbon resistant to wet chemical oxidation (hard carbon) or thermal oxidation (soot carbon); atomic H/O ratios indicated a close correlation between the degree of reduction of the NOM and its rigidity. Sorbents with larger rigid carbon fractions had more non-linear sorption isotherms and higher organic carbon (OC) normalized sorption affinities. The size of the PM hole filling domain for a given sorbent was closely correlated with the extent to which the sorbent's affinity for chlorobenzenes exceeded predictions from a linear free energy relationship. Loss of some portions of the rigid character of the NOM domain due to the penetration of sorbate molecules (plasticization) was discussed as a possible contributor to the non-ideal sorption behaviors observed in this study. The existence of a permanently rigid NOM domain, not subject to plasticization under environmental conditions, was postulated as an additional factor determining the observed sorption behavior.