Alteration of ferrihydrite reductive dissolution and transformation by adsorbed As and structural Al: Implications for As retention
Alteration of ferrihydrite reductive dissolution and transformation by adsorbed As and structural Al: Implications for As retention
复制标题
DOI：
10.1016/j.gca.2010.11.016
复制
发表时间：
2011-02-01
影响因子：
5
通讯作者：
Fendorf, Scott
中科院分区：
文献类型：
--
作者：
Masue-Slowey, Yoko;Loeppert, Richard H.;Fendorf, Scott
As(V)的还原和Fe（氢）氧化物的还原性溶解和转化是控制As在土壤和沉积物中滞留的两个主要过程。当在土壤和沉积物中形成时，铁（水合）氧化物通常含有各种杂质-Al是最突出的杂质之一，但对于铁（水合）氧化物中的结构Al如何改变其生物转化和随后的As保留知之甚少。通过对铁（II）和希瓦氏菌属ANA-3进行间歇和平流柱研究，我们检验了(I)结构铝对水合铁（一种高活性的氢氧化铁）的还原溶解和转化的影响程度，以及(2)吸附的砷对（Al取代的）水合铁的溶解和转化以及随后的砷保留的影响。结构铝降低了铁水合体还原转变的程度；与纯双线水合铁相比，诱导al -铁水合铁转变所需的铁（II）浓度要高近3个数量级。结构Al降低了铁（II）在水合铁上的保留/掺入，阻碍了铁（II）催化的水合铁的转化：此外，由于铁（II）诱导的向次级产物的转化停止，在与Shewanella sp. ANA-3反应时，与纯水合铁相比，水合铁Al （II）溶解（不一致）程度更大。此外，As(V)对Al-ferrihydrite的吸附完全阻止了Fe（II）催化的水合铁的转化，并减小了Shewanella sp. ANA-3对水合铁和Al-ferrihydrite还原速度和程度的差异。我们的研究进一步表明，Al-ferrihydrite的还原性溶解导致Al位点的富集，并且由于As（III）对这些非铁位点的亲和力较低，As(V)的还原加速了As的释放。(C) 2010 Elsevier Ltd.版权所有。
Reduction of As(V) and reductive dissolution and transformation of Fe (hydr)oxides are two dominant processes controlling As retention in soils and sediments. When developed within soils and sediments, Fe (hydr)oxides typically contain various impurities-Al being one of the most prominent but little is known about how structural Al within Fe (hydr)oxides alters its biotransformation and subsequent As retention. Using a combination of batch and advective flow column studies with Fe(II) and Shewanella sp. ANA-3, we examined (I) the extent to which structural Al influences reductive dissolution and transformations of ferrihydrite, a highly reactive Fe hydroxide, and (2) the impact of a0dsorbed As on dissolution and transformation of (Al-substituted) ferrihydrite and subsequent As retention. Structural Al diminishes the extent of ferrihydrite reductive transformation; nearly three-orders of magnitude greater concentration of Fe(II) is required to induce Al-ferrihydrite transformation compared to pure two-line ferrihydrite. Structural Al decreases Fe(II) retention/incorporation on/into ferrihydrite and impedes Fe(II)-catalyzed transformation of ferrihydrite: Moreover, owing to cessation of Fe(II)-induced transformation to secondary products, Al-ferrihydrite dissolves (incongruently) to a greater extent compared to pure ferrihydrite during reaction with Shewanella sp. ANA-3. Additionally, adsorption of As(V) to Al-ferrihydrite completely arrests Fe(II)-catalyzed transformation of ferrihydrite, and it diminishes the difference in the rate and extent of ferrihydrite and Al-ferrihydrite reduction by Shewanella sp. ANA-3. Our study further shows that reductive dissolution of Al-ferrihydrite results in enrichment of Al sites, and As(V) reduction accelerates As release due to the low affinity of As(III) on these non-ferric sites. (C) 2010 Elsevier Ltd. All rights reserved.