Zeolite-supported nanoscale zero-valent iron: New findings on simultaneous adsorption of Cd(II), Pb(II), and As(III) in aqueous solution and soil
Zeolite-supported nanoscale zero-valent iron: New findings on simultaneous adsorption of Cd(II), Pb(II), and As(III) in aqueous solution and soil
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DOI：
10.1016/j.jhazmat.2017.09.036
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发表时间：
2018-02-15
影响因子：
13.6
通讯作者：
Brookes, Philip
中科院分区：
文献类型：
--
作者：
Li, Zhangtao;Wang, Lu;Brookes, Philip
纳米零价铁（NZVI）对重金属具有很强的吸附能力，但易形成团聚体。在这项研究中，沸石负载纳米零价铁（Z-NZVI）的合成从一个简化的液相还原铁（III）盐，同时吸附As（III），镉（II）和铅（II）从水溶液和土壤。扫描电镜结果表明，NZVI在沸石表面的分散均匀，团聚现象得到消除。红外光谱分析表明，NZVI在Z-NZVI表面得到了有效的保护。XRD和XPS分析结果表明，Z-NZVI吸附后生成了Cd（OH）2、Pb和FeAsO 4。在pH 6时，Z-NZVI对As（III）、Cd（II）和Pb（II）的最大吸附容量分别为11.52 mg/g、48.63 mg/g和85.37 mg/g，远高于沸石。批实验表明，多种吸附机制，包括静电吸附，离子交换，氧化，还原，共沉淀，络合物与选定的重金属共存。由于Z-NZVI上形成多相化合物，重金属之间的协同作用和竞争作用并存。30 g/kg的Z-NZVI对土壤样品中的大部分砷、镉和铅都有固定作用。这些结果表明，Z-NZVI具有很大的潜力，用于处理水和土壤多重污染的重金属。(C)2017爱思唯尔B. V.保留所有权利。
Nanoscale zero-valent iron (NZVI) has a high adsorption capacity for heavy metals, but it forms aggregates easily. In this study, zeolite-supported nanoscale zero-valent iron (Z-NZVI) was synthesized from a simplified liquid-phase reduction of iron(III) salts which simultaneously adsorbed As(III), Cd(II) and Pb(II) from aqueous solution and soil. Scanning electron micrographs showed that aggregation was eliminated and the NZVI evenly dispersed onto the surface of zeolite. FTIR spectra reveal that NZVI was protected from oxidization on the surface of Z-NZVI. XRD and XPS patterns confirmed the formation of Cd(OH)2, Pb, and FeAsO4 in Z-NZVI after adsorption. The experimental maximum adsorption capacity of Z-NZVI was 11.52 mg As(III)/g, 48.63 mg Cd(II)/g, and 85.37 mg Pb(II)/g at pH 6, respectively, much higher than that of zeolite. Batch experiments indicate that various adsorption mechanisms including electrostatic adsorption, ionic exchange, oxidation, reduction, co-precipitation, and complexation coexisted with the selected heavy metals. Due to the formation of multiphase compounds on the Z-NZVI, the synergy and competition among heavy metals were concurrent. Most arsenic, cadmium and lead in the soil samples were immobilized after mixing with 30 g/kg Z-NZVI. These results suggest that Z-NZVI has great potential for treating water and soil multi-contaminated with heavy metals. (C) 2017 Elsevier B.V. All rights reserved.