Mechanism of arsenate mobilization from goethite by aliphatic carboxylic acid
Mechanism of arsenate mobilization from goethite by aliphatic carboxylic acid
复制标题
脂肪族羧酸从针铁矿中动员砷酸盐的机理
DOI：
10.1016/j.jhazmat.2008.07.068
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发表时间：
2009-04-30
影响因子：
13.6
通讯作者：
Yao, Shuhua
中科院分区：
文献类型：
--
作者：
Shi, Rong;Jia, Yongfeng;Yao, Shuhua
砷具有剧毒，因此对环境和人类健康构成潜在威胁。自然环境中砷的迁移性和固定性受到共存溶解的天然有机酸的显着影响，由于天然有机物的分解以及植物根系和微生物的代谢，这些天然有机酸广泛存在于土壤和沉积物中。最近有报道称，在较低的 pH 值下，柠檬酸盐通过竞争吸附降低了砷酸盐在金属氧化物上的吸附。本研究研究了不同接触顺序的平衡针铁矿-砷酸盐-柠檬酸盐体系中柠檬酸盐促进针铁矿溶解与柠檬酸盐抑制砷酸盐吸附之间的关系。结果表明，砷酸盐吸附的抑制与针铁矿的溶解之间存在明显的相关性。比较了柠檬酸盐 (1.0 mM)、草酸盐 (1.5 mM) 和乙酸盐 (3.0 mM) 存在下的砷酸盐吸附和针铁矿溶解情况。结果表明，三种有机酸中柠檬酸盐对砷酸盐吸附的抑制最为显着。尽管草酸盐更显着地溶解针铁矿，但它对砷酸盐吸附的抑制作用远小于柠檬酸盐。因此，有人提出，在较低pH值下，柠檬酸盐对砷酸盐吸附的减少中，结合位点的竞争而不是柠檬酸盐促进的针铁矿溶解发挥了关键作用。 (C) 2008 Elsevier B.V. 保留所有权利。
Arsenic is highly toxic and therefore represents a potential threat to the environment and human health. The mobility and fixation of arsenic in natural environment is significantly affected by co-occurring dissolved natural organic acids, which are widely present in soils and sediments due to the decomposition of natural organic matters and the metabolism of plant roots and microorganisms. It was reported recently that at lower pH, citrate decreased arsenate adsorption on metal oxides as the result of competitive adsorption. This study examined the relationship between citrate-promoted goethite dissolution and citrate-suppressed arsenate adsorption in the equilibrated goethite-arsenate-citrate systems with different contact orders. The results indicated that there is obvious correlation between the suppression of arsenate adsorption and dissolution of goethite. Arsenate adsorption and goethite dissolution in the presence of citrate (1.0 mM), oxalate (1.5 mM) and acetate (3.0 mM) were compared. The results showed that arsenate adsorption was most significantly inhibited by citrate among the three organic acids. Although oxalate dissolved goethite more significantly, it inhibited arsenate adsorption much less than citrate. Hence it is proposed that the competition for binding sites rather than citrate-promoted goethite dissolution played a key role in the reduction of arsenate adsorption by citrate at lower pH. (C) 2008 Elsevier B.V. All rights reserved.