Department of Municipal Water and Infrastructure, UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA, Delft, The Netherlands.
Water Sci Technol. 2009;60(9):2353-63. doi: 10.2166/wst.2009.597.
For the removal of iron from groundwater, aeration followed with rapid (sand) filtration is frequently applied. Iron removal in this process is achieved through oxidation of Fe(2 + ) in aqueous solution followed by floc formation as well as adsorption of Fe(2 + ) onto the filter media. The rate of oxidation of the adsorbed Fe(2 + ) on the filter media plays an important role in this removal process. This study focuses on investigating the effect of pH on the rate of oxidation of adsorbed Fe(2 + ). Fe(2 + ) has been adsorbed, under anoxic conditions, on iron oxide coated sand (IOCS) in a short filter column and subsequently oxidized by feeding the column with aerated water. Ferrous ions adsorbed at pH 5, 6, 7 and 8 demonstrated consumption of oxygen, when aerated water was fed into the column. The oxygen uptake at pH 7 and 8 was faster than at pH 5 and 6. However the difference was less pronounced than expected. The difference is attributed to the pH buffering effect of the IOCS. At feedwater pH 5, 6 and 7 the pH in the effluent was higher than in the influent, while a pH drop should occur because of oxidation of adsorbed Fe(2 + ). At pH 8, the pH dropped. These phenomena are attributed to the presence of calcium and /or ferrous carbonate in IOCS.
为了去除地下水中的铁，通常采用曝气后快速（砂）过滤的方法。在这个过程中，铁的去除是通过氧化水溶液中的 Fe(2 + ) 来实现的，随后形成絮体并吸附到过滤介质上。吸附在过滤介质上的 Fe(2 + ) 的氧化速率在这个去除过程中起着重要作用。本研究重点研究 pH 值对吸附的 Fe(2 + ) 的氧化速率的影响。在缺氧条件下，将 Fe(2 + ) 吸附在涂有氧化铁的砂（IOCS）上，然后通过向柱中供应充气水来氧化。当向柱中供应充气水时，吸附在 pH 值为 5、6、7 和 8 的亚铁离子消耗氧气。在 pH 值为 7 和 8 时的氧气吸收速度比在 pH 值为 5 和 6 时更快。然而，差异并不像预期的那么明显。这种差异归因于 IOCS 的 pH 值缓冲效应。在进水 pH 值为 5、6 和 7 时，出水的 pH 值高于进水的 pH 值，而由于吸附的 Fe(2 + ) 的氧化，pH 值应该下降。在 pH 值为 8 时，pH 值下降。这些现象归因于 IOCS 中存在钙和/或亚铁碳酸盐。
Zotero 插件