کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4486273 1316981 2005 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Coupling enhanced water solubilization with cyclodextrin to indirect electrochemical treatment for pentachlorophenol contaminated soil remediation
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Coupling enhanced water solubilization with cyclodextrin to indirect electrochemical treatment for pentachlorophenol contaminated soil remediation
چکیده انگلیسی

This study undertakes to examine, at laboratory scale, the technical feasibility, mechanisms and performances provided by coupling the enhanced flushing abilities of cyclodextrin solutions for pentachlorophenol (PCP) removal from contaminated soil with indirect electrochemical treatment for the final disposal of soil extract solutions containing high PCP loads (0.77 mmol L−1). The hydroxypropyl-β-cyclodextrin (HPCD) solution increased the aqueous concentration of PCP in soil extract effluents to as much as 3.5 times the concentrations obtained during the water flush of the soil. PCP was treated with electrochemically generated Fenton's reagent in an aqueous medium. The increase in PCP water solubility in the presence of HPCD is balanced by the corresponding decrease in PCP degradation rate under indirect electrochemical treatment. This is due to the high carbon content (HPCD and dissolved natural organic matter) in the soil extract solutions, which compete for the non-selective hydroxyl radical reaction to PCP. However, our results indicate that HPCD has a beneficial effect on the degradation rates of PCP. This relative improvement in PCP degradation could be explained by the formation of the ternary complex (PCP-cyclodextrin-iron) which may direct hydroxyl reaction to PCP and which would, in any case, justify the use of a Fenton -like process for the final treatment of soil extract solutions. Total disappearance of PCP and 90% abatement of the chemical oxygen demand were achieved within an 11 h electrolysis treatment time. Elucidation of the PCP degradation pathway indicates that after successive PCP hydroxylations, oxidative opening of the PCP aromatic ring quickly occurred, leading to small unstable non-chlorinated or partially chlorinated short chain carboxylic acids, such as monochloroacetic and dichloromaleic acid. Determination of the concentration of these acids shows that indirect electrochemical treatment leads to oxalic acid accumulation in aqueous solutions treated. A decrease in toxicity was observed at the end of the treatment time.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Water Research - Volume 39, Issue 12, July 2005, Pages 2763–2773
نویسندگان
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