Characteristics and influencing factors of tetrachloroethylene sorption–desorption on soil and its components. (February 2016)

• Record Type: Journal Article
• Authors: Qiu, Zhaofu; Yang, Weiwei; He, Long; Zhao, Zhexuan; Lu, Shuguang; Sui, Qian
• Is Part Of: Chemosphere. Volume 144(2016)
• Page Start: 895
• Page End: 901
• Publication Date: 2016-02
• Subjects: Tetrachloroethylene (PCE) -- Soil adsorption -- Desorption hysteresis -- Ionic strength; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.09.047
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: To investigate the effects of soil structure, soil organic carbon (SOC), minerals, initial tetrachloroethylene (PCE) concentration ( C 0 ), and ionic strength ( C i ) on PCE sorption–desorption, six types of soil were adopted as adsorbents, including two types of natural soil and four types of soil with most of the "soft carbon" pre-treated by H2 O2 or with all SOC removed from the original soil by 600 °C ignition. The results showed that all of the sorption–desorption isotherms of PCE were non-linear within the experimental range, and the H2 O2 -treated samples exhibited higher non-linear sorption isotherms than those of the original soils. The hysteresis index of PCE sorption to original soil is less pronounced than that of the H2 O2 -treated and 600 °C-heated samples due to the entrapment of sorbate molecules in the "hard carbon" domain, together with the meso- and microporous structures within the 600 °C-heated samples. Both SOC and minerals have impacts on the sorption–desorption of PCE, and the sorption–desorption contribution rate of minerals increased with decreasing SOC content. C 0 has almost no influence on the sorption to minerals of the soils, but the contribution rate of minerals decreased with increasing C 0 in the desorption stage. As a result of the salting-out effect, PCE sorption capacity was increased by increasing C i, especially when C i ≥ 0.1 M. Moreover, desorption increased and hysteresis weakened with increasing C i, except for the 600 °C-heated samples. In addition, no significant effect of C i on desorption of PCE and no hysteresis was observed in this experimental range for the 600 °C-heated samples. Highlights: All of the sorption–desorption isotherms of PCE on different soils were non-linear. The hysteresis index of PCE sorption to pre-treated soils was more pronounced. The sorption–desorption contribution rate of minerals raised with decreasing SOC. For the 600 °C-heated soils, ionic strength had no effect on PCE desorption.