The stability of Fe(III)-As(V) co-precipitate in the presence of ascorbic acid: Effect of pH and Fe/As molar ratio
The stability of Fe(III)-As(V) co-precipitate in the presence of ascorbic acid: Effect of pH and Fe/As molar ratio
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抗坏血酸存在下 Fe(III)-As(V) 共沉淀物的稳定性：pH 值和 Fe/As 摩尔比的影响
DOI：
10.1016/j.chemosphere.2018.11.142
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发表时间：
2019
期刊：
影响因子：
8.8
通讯作者：
Jia Yongfeng
中科院分区：
文献类型：
--
作者：
Yuan ZidanYuan;Zhang Guoqing;Lin Jinru;Zeng Xiangfeng;Ma Xu;Wang Xin;Wang Shaofeng;Jia Yongfeng
Fe(III)-As(V) 共沉淀物在还原条件下的潜在危害尚不完全清楚。本工作研究了抗坏血酸 (AH2) 还原 Fe(III) 对不同 pH 值和 Fe/As 摩尔比下 Fe(III)-As(V) 共沉淀物稳定性的影响。结果表明，在 pH 5-9 时，通过共沉淀物（Fe/As 摩尔比为 3 和 5）还原 79.9-97.5% Fe(III)，As (14-98.9%) 和 Fe (27.9-99.3%) 显着释放到溶液中。随着 pH 值 (6-9) 的增加或 Fe/As 摩尔比的降低（从 5 到 3），观察到更多的 As 释放。这可能是由于 AH2 分解的最终产物草酸盐在较高 pH 值或较低 Fe/As 摩尔比下与 As(V) 强烈竞争 Fe(II)，从而抑制副复合体积累，从而导致更多的 As 动员。 Fe(III)还原后Fe(III)-As(V)与AH2共沉淀物的稳定性低于有氧环境中的稳定性。与对苯二酚(QH2)存在下生成的Fe(II,III)(氢)氧化物相比，Fe(III)-As(V)共沉淀物与AH2长期反应时形成了洪堡石。这项研究的结果表明，副复合体和洪堡石作为次级固体产物与环境相关，并且主要负责 As(V) 和 Fe(II) 的固定。
The potential hazards of Fe(III)-As(V) co-precipitate under reducing conditions are incompletely known. This work investigated the effect of Fe(III) reduction by ascorbic acid (AH2) on the stability of Fe(III)-As(V) co-precipitate at different pHs and Fe/As molar ratios. The results showed that As (14–98.9%) and Fe (27.9–99.3%) were significantly released into solution by 79.9–97.5% Fe(III) reduction of the co-precipitate (Fe/As molar ratios of 3 and 5) at pH 5–9. More As release was observed with the increase of pH (6–9) or decrease in Fe/As molar ratio (from 5 to 3). This could be attributed by oxalate, the final product of AH2decomposition, which strongly competed with As(V) for Fe(II) at higher pH or lower Fe/As molar ratio, inhibiting parasymplesite accumulation and then causing more As mobilization. The stability of Fe(III)-As(V) co-precipitate with AH2upon Fe(III) reduction was lower than that in oxic environment. Compared with produced Fe(II,III) (hydr)oxides in the presence of hydroquinone (QH2), humboldtine was formed during the long-term reactions of Fe(III)-As(V) co-precipitate with AH2. The findings of this study implied that parasymplesite and humboldtine as secondary solid products were environmental relevant and mainly responsible for As(V) and Fe(II) immobilization.