Role of Humic Substances on Cr(VI) Removal from Groundwater with Pyrite

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• 作者：Cetin Kantar ; Muhammet Samet Bulbul ; Selda Keskin
• 关键词：Pyrite ; Humic acid ; Chromium ; Permeable reactive barrier (PRB) ; Reduction
• 刊名：Water, Air, & Soil Pollution
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：228
• 期：1
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment, general; Water Quality/Water Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Soil Science & Conservation; Hydrogeology; Climate Change/Climate Change Impacts;
• 出版者：Springer International Publishing
• ISSN：1573-2932
• 卷排序：228

文摘

Groundwater composition may have a pronounced impact on long-term performance of permeable reactive barriers (PRBs). Here, batch and column experiments were conducted to investigate the effects of humic acid (HA) on Cr(VI) removal by pyrite in systems containing cations such as Ca2+ and Mg2+. HA was observed to have inhibitory effect on Cr(VI) uptake by pyrite under the experimental conditions studied (e.g., pH 3 to 8). HA sorbed onto pyrite surface and thus (1) competed against Cr(VI) for pyritic surface sites and/or (2) increased electrostatic repulsion between Cr(VI) and pyrite. In systems with HA and Ca2+/Mg2+, the Cr(VI) uptake by pyrite decreased drastically relative to HA alone due to the aggregation of HA with Ca2+/Mg2+. The formation of such HA aggregates/precipitates blocked Cr(VI) ions to reach its binding sites, thereby resulting in a substantial decrease in Cr(VI) uptake. Overall, the results have major implications for proper design and operation of PRBs with pyrite as the reactive material.