Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Mol, Belgium.
J Hazard Mater. 2010 Sep 15;181(1-3):217-25. doi: 10.1016/j.jhazmat.2010.04.119. Epub 2010 May 6.
In situ bioprecipitation (ISBP), which involves immobilizing the metals as precipitates (mainly sulphides) in the solid phase, is an effective method of metal removal from contaminated groundwater. This study investigated the stability of metal precipitates formed after ISBP in two different solid-liquid matrices (artificial and natural). The artificial matrix consisted of sand, Zn (200 mg L(-1)), artificial groundwater and a carbon source (electron donor). Here the stability of the Zn precipitates was evaluated by manipulation of redox and pH. The natural system matrices included aquifer material and groundwater samples collected from three different metal (Zn and Co) contaminated sites and different carbon sources were provided as electron donors. In the natural matrices, metal precipitates stability was assessed by changing aquifer redox conditions, sequential extraction, and BIOMET assay. The results indicated that, in the artificial matrix, redox manipulation did not impact the Zn precipitates. However the sequential pH change proved detrimental, releasing 58% of the precipitated Zn back into liquid phase. In natural matrices, the applied carbon source largely affected the stability of metal precipitates. Elemental analysis performed on the precipitates formed in natural matrix showed that the main elements of the precipitates were sulphur with Zn and Co.
原位生物沉淀（ISBP）是一种将金属固定为沉淀物（主要是硫化物）的有效方法，可用于从受污染的地下水中去除金属。本研究调查了在两种不同的固液基质（人工和天然）中形成的金属沉淀物的稳定性。人工基质由沙子、Zn（200mg/L）、人工地下水和碳源（电子供体）组成。在这里，通过操纵氧化还原和 pH 值来评估 Zn 沉淀物的稳定性。天然系统基质包括从三个不同金属（Zn 和 Co）污染地点采集的含水层材料和地下水样本，并提供不同的碳源作为电子供体。在天然基质中，通过改变含水层的氧化还原条件、顺序提取和 BIOMET 测定来评估金属沉淀物的稳定性。结果表明，在人工基质中，氧化还原操作不会影响 Zn 沉淀物。然而，顺序 pH 变化证明是有害的，将 58%的沉淀 Zn 释放回液相。在天然基质中，所施加的碳源会极大地影响金属沉淀物的稳定性。对天然基质中形成的沉淀物进行的元素分析表明，沉淀物的主要元素是硫，还有 Zn 和 Co。
