Overlooked encounter process that affects physical behaviors of stabilized nanoscale zero-valent iron during in situ groundwater remediation
Overlooked encounter process that affects physical behaviors of stabilized nanoscale zero-valent iron during in situ groundwater remediation
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DOI：
10.1016/j.jhazmat.2023.132547
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发表时间：
2023-09-16
影响因子：
13.6
通讯作者：
Hu，Yi-bo
中科院分区：
文献类型：
--
作者：
Xie，Yujie;Zhang，Miaoyue;Hu，Yi-bo
地下水基质与注入纳米零价铁（nanoscale zero-valent iron， NZVI）进行原位修复的动态相遇影响了NZVI的迁移能力，但目前尚未得到很好的认识。以聚丙烯酸（PAA）稳定的NZVI （NZVI - PAA）和Mg(OH)2包覆的NZVI （NZVI@Mg(OH)2）分别作为具有代表性的静电斥力增强和磁场吸引力减弱的NZVI。与二价阳离子和腐植酸（HA）接触，由于Lewis酸碱相互作用和异聚集，诱导了NZVI-PAA的剧烈聚集和沉降（预沉降）。此外，遇到的地下水电解质不能有效地为NZVI-PAA提供静电斥力，导致突破成熟动力学。声波法将NZVI浆料与地下水混合后，可以消除和忽略NZVI - paa的预沉降和熟化行为。相比之下，相遇过程对NZVI@Mg(OH)2几乎没有影响，沉降受到阻碍。虽然颗粒收集器的吸引力促进了NZVI@Mg(OH)2在原始和混合包覆砂上的吸附，但NZVI@Mg(OH)2突破的朗木连阻塞动力学表明，在砂表面吸附位点耗尽后，NZVI@Mg(OH)2突破具有高迁移率。扩展的Derjaguin - Landau - Verwey - Overbeek分析和输运模型揭示了相遇对不同稳定NZVIs物理行为的影响，在不同地下条件下的实际应用中应考虑这些影响。
Dynamic encountering between groundwater matrices and nanoscale zero-valent iron (NZVI) injected forin situsubsurface remediation affects NZVI’s mobility and has not been well recognized. Polyacrylic acid (PAA)-stabilized NZVI (NZVI–PAA) and Mg(OH)2-coated NZVI (NZVI@Mg(OH)2) were investigated as representative NZVIs stabilized by enhanced electrostatic repulsion and reduced magnetic attraction, respectively. Encounters with divalent cations and humic acid (HA) induced the drastic aggregation and sedimentation (presedimentation) of NZVI–PAA owing to Lewis acid–base interactions and heteroaggregation. In addition, encountered groundwater electrolytes could not effectively provide electrostatic repulsion for NZVI–PAA, resulting in breakthrough ripening dynamics. The presedimentation and ripening behaviors of NZVI–PAA were eliminated and unheeded after mixing the NZVI slurry with groundwater by sonication. In comparison, the encountering process barely impacted NZVI@Mg(OH)2, for which settling was hindered. Although the particle–collector attraction promoted NZVI@Mg(OH)2adsorption on pristine and hybrid-coated sands, theLangmuirianblocking dynamics of the NZVI@Mg(OH)2breakthrough demonstrated its high mobility after adsorption sites of sand surface were exhausted. Extended Derjaguin−Landau−Verwey−Overbeek analysis and transport modeling provided insights into overlooked effects of encountering on physical behaviors of different stabilized NZVIs, which should be considered during practical applications under diverse subsurface conditions.