Carbo-Iron - An Fe/AC composite - As alternative to nano-iron for groundwater treatment

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• 作者：Katrin Mackenzie ; ^{katrin.mackenzie@ufz.de} ; Steffen Bleyl ; Anett Georgi ; Frank-Dieter Kopinke
• 关键词：In-situ groundwater remediation ; Injectable colloids ; nZVI ; Fe/AC ; Composite ; Dechlorination ; Carbo-Iron
• 刊名：Water Research
• 出版年：2012
• 期刊代码：57_00431354
• 类别：civ
• 出版时间：August, 2012
• 卷：46
• 期：12
• 页码：3817-3826
• 文件大小：596 K

摘要

Carbo-Iron^庐 is a novel colloidal composite consisting of activated carbon colloids (ACC) with a d₅₀ particle size of 0.8聽渭m and anchored deposits of zero-valent iron clusters. This study discusses the principal material properties of Carbo-Iron colloids (CIC) relevant for groundwater treatment in comparison to commercially available nano-sized zero-valent iron (nZVI). CIC with 10-25聽wt%Fe⁰ have been developed and tested in laboratory studies for their suitability as dehalogenation reagent and are especially designed to overcome some limitations known from the utilization of nZVI: CIC combine the sorption properties of ACC and the chemical reactivity of nZVI. In column tests, flushed-in CIC showed an enhanced mobility in sediment material compared to nZVI, without the need for colloid stabilizers. However, adding 1-3聽wt-%of carboxymethyl cellulose (CMC) related to CIC as colloid stabilizer was found to assure long-lived stable suspensions under laboratory conditions which may additionally support the already improved mobility of the CIC and the homogeneity of particle deposition on the sediment matrix. The hydrophobic character of the ACC carrier provides a high affinity of CIC to non-aqueous phase liquids (NAPL). In undisturbed flow, the reactive particles are collected at the water-NAPL interface. The reagent accumulation at the organic phase is necessary for a successful source attack.