Enhanced sequestration of Cr(VI) by copper doped sulfidated zerovalent iron (SZVI-Cu): Characterization, performance, and mechanisms
Enhanced sequestration of Cr(VI) by copper doped sulfidated zerovalent iron (SZVI-Cu): Characterization, performance, and mechanisms
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铜掺杂硫化零价铁 (SZVI-Cu) 增强 Cr(VI) 螯合：表征、性能和机制
DOI：
10.1016/j.cej.2019.02.058
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发表时间：
2019-06-15
影响因子：
15.1
通讯作者：
Xu, Chunhua
中科院分区：
文献类型：
--
作者：
Jia, Tiantian;Zhang, Bingliang;Xu, Chunhua
零价铁（ZVI）对Cr（VI）的螯合反应在水环境中具有自抑制性，限制了ZVI的应用。提出了一系列的改进策略。在本研究中，制备了铜硫化ZVI（SZVI-Cu）材料，通过沉积铜到硫化改性ZVI，以提高铬（VI）的封存效率和容量。通过对比实验，证明了SZVI-Cu与ZVI、硫化ZVI（SZVI）和铁铜（ZVI-Cu）在螯合Cr（VI）方面的优越性。此外，SZVI-Cu在4-8的宽pH范围内表现出显著的螯合Cr（VI）的能力。SZVI-Cu对Cr（VI）的固定效率在pH 8.0的条件下，20 min内达到97.9%，固定率是其他3种材料的2.4-59.7倍。通过批式实验考察了SZVI-Cu投加量、混合比等因素对去除效果的影响。在1，10-菲咯啉存在下，Cr（VI）的固定效率、Fe（II）的生成速率与Cr（VI）的抑制去除率呈正相关，表明Fe（II）对Cr（VI）的固定起着重要作用。机理分析表明，硫化促进了Fe（II）向杂质的电子转移，强化了Fe（II）从ZVI中的释放，而负载Cu-0也有利于Fe（II）的生成，这是由于两种金属之间的电位差。Cu与ZVI结合作为原电池不仅加快了反应速率，而且增加了Cr（VI）的螯合能力。SZVICu在很宽的pH范围内具有快速有效的螯合Cr（VI）的潜力。
The reactivity of zero valent iron (ZVI) for sequestering Cr(VI) is self-inhibiting in aquatic environments, which limits the application of ZVI. A series of improvement strategies have been proposed. In this study, a coppersulfidated ZVI (SZVI-Cu) material was prepared by depositing copper onto sulfidation modified ZVI to enhance the sequestration efficiency and capacity of Cr(VI). Comparative experiments were used to demonstrate the superiority of SZVI-Cu for sequestration of Cr(VI) with ZVI, sulfidated ZVI (SZVI) and iron-copper (ZVI-Cu). In addition, SZVI-Cu exhibited a prominent ability for sequestration of Cr(VI) over a wide pH range of 4-8. The sequestration efficiency of Cr(VI) by SZVI-Cu reached 97.9% within 20 min even at pH 8.0, and the sequestration rate of Cr(VI) increased 2.4-59.7 folds compared with other three materials. Batch experiments were also used to evaluate the removal efficiency under various factors such as SZVI-Cu dosage and mixing rate. The positive correlation between the sequestration efficiency of Cr(VI), the produced rate of Fe(II) and the inhibited removal of Cr(VI) in the presence of 1,10-phenanthroline indicated that Fe(II) played an important role to the sequestration of Cr(VI). The mechanism analysis showed that sulfidation can facilitate the electron transfer from iron metal to contaminant and strengthen Fe(II) releasing from ZVI, and loading Cu-0 can also be conducive to the production of Fe(II) due to the potential difference between the two metals. Cu combined with ZVI function as galvanic cells not only accelerates the reaction rate but also increases the sequestration capacity of Cr(VI). SZVICu is promising for rapid and effective sequestration of Cr(VI) over a wide pH range.