Phenanthrene sorption/desorption sequences provide new insight to explain high sorption coefficients in field studies

• Published in: Chemosphere (Oxford) Vol. 84; no. 11; pp. 1578 - 1583
• Main Authors: Pan, Bo, Tao, Shu, Wu, Di, Zhang, Di, Peng, Hongbo, Xing, Baoshan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.09.2011; Elsevier
• Subjects: Adsorption; Applied sciences; Balancing; Contact; Desorption; Diffusion; Discharge; Environmental Pollutants - chemistry; Exact sciences and technology; Hexanes - chemistry; Humin; Hysteresis; Persistent organic pollutants; Phenanthrene; Phenanthrenes - chemistry; Pollution; Sequestration; Soil; Sorption; Spectrometry, Fluorescence; Swelling; Humin; Swelling; Persistent organic pollutants; Discharge; Hysteresis; Sequestration; Organic matter; Phenanthrene; Hydrocarbon; Prediction; Adsorption capacity; Desorption; Polycyclic aromatic compound; Mutagen; Persistent organic pollutant; Sorption; Carcinogen; Kinetics; Sorbent; Comparative study; Organic compounds
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2011.05.051

► Big variations were observed for sorption coefficients from field and lab studies. ► We proposed that the unclear sorption history may be an additional reason. ► We observed strong desorption hysteresis in low-concentration multi-time sorption. ► Special research attention should be put on sorption history. The sorption coefficients obtained in field investigation vary greatly from laboratory sorption experiments. The possible reasons were discussed in literature. Observing the commonly reported desorption hysteresis, this study proposed that the unclear sorption history of the field study could also result in the diverse sorption coefficients. This study conducted a comparative study regarding phenanthrene sorption/desorption behavior in low-concentration multi-time sorption process and the commonly applied high-concentration one-time sorption process. The sorption coefficients determined during the desorption process were much higher than those at sorption process. Thus, the prediction of sorption coefficient should be related with sorption history. Desorption hysteresis was increased with increased equilibration time and decreased solid-phase concentration. In addition, although the apparent contact time between sorbate and sorbent was shorter for low-concentration multi-time sorption, the desorption hysteresis was much stronger, which consequently result in higher sorption coefficients in comparison to high-concentration one-time sorption. Pore swelling or diffusion-controlled sorption kinetics could not explain this phenomenon. This study calls for research attention on sorption history, especially for field investigations.