Hydroxypropyl--Cyclodextrin-Mediated Iron-Activated Persulfate Oxidation of Trichloroethylene and Tetrachloroethylene

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• 作者：Chenju Liang ; Chiu-Fen Huang ; Nihar Mohanty ; Chih-Jen Lu ; Rama Mohan Kurakalva
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2007
• 出版时间：September 26, 2007
• 年：2007
• 卷：46
• 期：20
• 页码：6466 - 6479
• 全文大小：423K
• 年卷期：v.46,no.20(September 26, 2007)
• ISSN：1520-5045

文摘

Trichloroethylene (TCE) and tetrachloroethylene (PCE) are commonly found contaminants in soiland groundwater. However, the persulfate anion (S₂O₈^2-) is an oxidant; when activated with ferrouscation (Fe²⁺), it generates a stronger oxidant (known as a sulfate free radical, SO₄^-), which may be usedfor the destruction of contaminants. Hydroxypropyl--cyclodextrins (HP--CDs) are environmentallybenign glucose-based molecules that have the ability to increase the solubility of contaminants such as TCEand PCE and make them more amenable to degradation by chemical oxidation. The ultraviolet (UV) andhydrogen nuclear magnetic resonance (¹H NMR) spectra of various inclusion complexes of HP--CD, Fe²⁺cations, and TCE showed that HP--CD forms inclusion complexes with organics, Fe²⁺ cations, andcombinations thereof. The apparent solubilities of TCE and PCE in aqueous solutions that contain HP--CDwere observed to increase linearly with concentration. When persulfate was activated by the continuous additionof Fe²⁺ cations in a system where TCE and PCE were present as dense nonaqueous phase liquids (DNAPLs),the presence of HP--CD increased the dissolved contaminant concentrations and the contaminantswere attacked preferentially, most likely because of a controlled and slower rate of generation of the SO₄^-species.