Immobilization of Mercury by Carboxymethyl Cellulose Stabilized Iron Sulfide Nanoparticles: Reaction Mechanisms and Effects of Stabilizer and Water Chemistry
Immobilization of Mercury by Carboxymethyl Cellulose Stabilized Iron Sulfide Nanoparticles: Reaction Mechanisms and Effects of Stabilizer and Water Chemistry
复制标题
羧甲基纤维素稳定的硫化铁纳米粒子固定汞：反应机理以及稳定剂和水化学的影响
DOI：
10.1021/es404418a
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发表时间：
2014-04-01
影响因子：
11.4
通讯作者：
Zhao, Dongye
中科院分区：
文献类型：
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作者：
Gong, Yanyan;Liu, Yuanyuan;Zhao, Dongye
以羧甲基纤维素钠（CMC）为稳定剂制备了硫化铁（FeS）纳米粒子，并测试了其对水溶液中汞（Hg 2+）的去除效果。CMC在>= 0.03wt%时完全稳定0.5g/L的FeS（即，CMC与FeS的摩尔比>= 0.0006）。红外光谱表明，CMC分子通过双齿桥和氢键连接到纳米粒子上。CMC-FeS的摩尔比从0增加到0.0006提高了20%的汞吸附能力，然而，从0.0010增加到0.0025的比例减少了14%的吸附。红外光谱和X射线衍射分析表明，沉淀（形成朱砂和偏朱砂），离子交换（形成Hg0.89Fe0.11S），和表面络合的汞去除的重要机制。一个伪二级动力学模型是能够解释的吸附动力学，而双模式的等温线模型被提出来模拟的等温线，它认为沉淀和吸附。在6.5-10.5的pH范围内观察到高的汞吸收，而在pH < 6时观察到显著的容量损失。高浓度的Cl-（>106 mg/L）和有机质（5 mg/L，以TOC计）对汞吸收有一定的抑制作用。固定化汞在pH中性以上保存2.5年仍保持稳定。
Iron sulfide (FeS) nanoparticles were prepared with sodium carboxymethyl cellulose (CMC) as a stabilizer, and tested for enhanced removal of aqueous mercury (Hg2+). CMC at >= 0.03 wt % fully stabilized 0.5 g/L of FeS (i.e., CMC-to-FeS molar ratio >= 0.0006). FTIR spectra suggested that CMC molecules were attached to the nanoparticles through bidentate bridging and hydrogen bonding. Increasing the CMC-to-FeS molar ratio from 0 to 0.0006 enhanced mercury sorption capacity by 20%; yet, increasing the ratio from 0.0010 to 0.0025 diminished the sorption by 14%. FTIR and XRD analyses suggested that precipitation (formation of cinnabar and metacinnabar), ion exchange (formation of Hg0.89Fe0.11S), and surface complexation were important mechanisms for mercury removal. A pseudo-second-order kinetic model was able to interpret the sorption kinetics, whereas a dual-mode isotherm model was proposed to simulate the isotherms, which considers precipitation and adsorption. High mercury uptake was observed over the pH range of 6.5-10.5, whereas significant capacity loss was observed at pH < 6. High concentrations of Cl- (>106 mg/L) and organic matter (5 mg/L as TOC) modestly inhibited mercury uptake. The immobilized mercury remained stable when preserved for 2.5 years at pH above neutral.