Assessment of long-term performance and chromate reduction mechanisms in a field scale permeable reactive barrier.
Assessment of long-term performance and chromate reduction mechanisms in a field scale permeable reactive barrier.
复制标题
DOI：
10.1021/es803526g
复制
发表时间：
2009-07
影响因子：
11.4
通讯作者：
Ibettina Flury;Jakob Frommer;U. Eggenberger;U. Mäder;M. Nachtegaal;R. Kretzschmar
中科院分区：
文献类型：
--
作者：
Ibettina Flury;Jakob Frommer;U. Eggenberger;U. Mäder;M. Nachtegaal;R. Kretzschmar
一个创新的渗透反应屏障的全面实施，包括双排充满零价铁刨花的圆柱体，用于铬酸盐修复，监测了四年。对固体样品进行了分析，以阐明(i)相关的腐蚀机制和产物，（ii）铬酸盐还原和固定化的途径，以及（iii）位于水文和地球化学复杂地下水制度下的屏障的长期性能。地下水和活性物质的采样和分析表明，在流入区形成一个氧化铁腐蚀区，在屏障中心和流出区形成一个厌氧铁腐蚀区。铬酸盐的还原主要局限于流入区。腐蚀皮的形成和厚度与取样时间、取样位置、取样深度以及腐蚀皮的大小、形状和石墨含量有关。x射线吸收精细结构光谱显示了两种不同的Cr（III）物质，它们很可能分别由均相和非均相氧化还原反应途径产生。PRB的使用寿命和长期有效性似乎主要受限于zvi -刨花的腐蚀速率降低，因为它具有较厚的铁-氢氧化物层。
An innovative full-scale implementation of a permeable reactive barrier, consisting of a double-row of cylinders filled with zerovalent iron shavings, for chromate remediation was monitored over four years. Solid samples were analyzed to elucidate (i) the relevant corrosion mechanisms and products, (ii) the pathways of chromate reduction and immobilization, and (iii) the long-term performance of the barrier situated in a hydrological and geochemical complex groundwater regime. Sampling and analysis of groundwater and reactive material revealed an oxidative iron corrosion zone evolving in the inflow and a zone of anaerobic iron corrosion in the center and outflow of the barrier. Chromate reduction was mainly confined to the inflow region. The formation and thickness of corrosion rinds depended on sampling time, position, and depth, as well as on the size, shape, and graphite content In the inflow, the corrosion rinds mostly consisted of goethite and ferrihydrite. X-ray absorption fine structure spectroscopy revealed two distinct Cr(III) species, most likely resulting from homogeneous and heterogeneous redox reaction pathways, respectively. The longevity and long-term effectiveness of the PRB appears to be primarily limited by reduced corrosion rates of the ZVI-shavings because of the thick layers of Fe-hydroxides.