Transport in Porous Media of Highly Concentrated Iron Micro- and Nanoparticles in the Presence of Xanthan Gum
Transport in Porous Media of Highly Concentrated Iron Micro- and Nanoparticles in the Presence of Xanthan Gum
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DOI：
10.1021/es901897d
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发表时间：
2009-12-01
影响因子：
11.4
通讯作者：
Sethi, Rajandrea
中科院分区：
文献类型：
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作者：
Dalla Vecchia, Elena;Luna, Michela;Sethi, Rajandrea
研究了黄原胶作为载体在多孔介质中输送高浓度纳米级和微级零价铁（分别为NZVI和MZVI）浆料的能力。以不同离子强度值（6 × 10(-3) mM或12.5 mM）的铁悬浮液（浓度为20 g/L，添加黄原胶（3 g/L））在0.46 m长柱中进行砂填充柱实验。通过在线连续测量磁化率获得的铁的突破曲线显示，在每个实验条件下，注入结束时（即在7或26孔体积后），MZVI的归一化洗脱浓度（>0.94）高于NZVI（>0.88）。另外沿柱的敏感性测量和压降也证实了MZVI比NZVI更容易洗脱。此外，注铁阶段后的冲水使注入铁总质量中MZVI的回收率超过95%，NZVI的回收率超过92%。试验证明，黄原胶是一种优良的稳定剂和ZVI颗粒的载体，在实际规模的修复干预中具有很高的应用潜力。
The ability of xanthan gum to act as a delivery vehicle for the transport in porous media of highly concentrated nano- and microscale zerovalent iron (NZVI and MZVI, respectively) slurries was investigated. Sand-packed column experiments were performed injecting iron suspensions at a concentration of 20 g/L, amended with xanthan gum (3 g/L), at different ionic strength values (6 x 10(-3) mM or 12.5 mM) in 0.46 m long columns. Breakthrough curves of iron, obtained by in-line continuous measurement of magnetic susceptibility, under each experimental condition showed that normalized elution concentration at the end of the injection (i.e., after 7 or 26 pore volumes) is higher for MZVI (>0.94) than for NZVI (>0.88). Additional susceptibility measurements along the column and pressure drop also confirmed that MZVI is more easily eluted than NZVI. Moreover, water flushing after the iron injection phase lead to recoveries of over 95% for MZVI, and over 92% for NZVI of the total injected iron mass. The tests proved that xanthan gum is an excellent stabilizing agent and delivery vehicle of ZVI particles and has a high potential for use in real scale remediation interventions.