Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron.
Remediating 1,4-dioxane-contaminated water with slow-release persulfate and zerovalent iron.
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DOI：
10.1016/j.chemosphere.2017.02.044
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发表时间：
2017-05
期刊：
影响因子：
8.8
通讯作者：
Harris CE
中科院分区：
文献类型：
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作者：
Kambhu A;Gren M;Tang W;Comfort S;Harris CE
1，4-二氧六环是一种新出现的污染物，与氯化溶剂一起用作腐蚀抑制剂。金属活化的过硫酸盐可以降解二氧六环，但反应动力学的特征通常是在前30分钟内快速降低，然后缓慢降低或没有进一步变化（即，平台）。我们的目标是确定导致该平台的因素，然后确定过硫酸钠和Fe 0的缓释制剂是否可以提供更可持续的降解处理。我们通过进行批处理实验来实现这一点，其中使用Fe 0活化的过硫酸盐来处理二氧六环。处理变量包括将二氧六环加入到Fe 0-过硫酸盐反应中的时间（T = 0和30 min），并包括在T=0 min时Fe 0-过硫酸盐反应的各种产物（Fe 2+、Fe 3+和SO 42 −）。结果表明，当在30 min时将二氧六环掺入反应中时，未发生降解;这与在T = 0 min时加入时观察到的60%降低形成鲜明对比。在开始（T= 0 min）时加入Fe 2+也严重停止反应并导致平台期。这表明由Fe 0-过硫酸盐反应产生的过量亚铁清除硫酸根并防止进一步的二氧六环降解。通过限制缓释蜡制剂中Fe 0的释放，避免了降解平台，并观察到100%的二氧六环去除。通过使用14 C-标记的二氧六环，我们表明，约40%的二氧六环碳在6天内矿化。这些数据支持使用缓释过硫酸盐和零价铁处理二氧六环污染的水。
1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe0-activated persulfate was used to treat dioxane. Treatment variables included the timing at which the dioxane was added to the Fe0-persulfate reaction (T = 0 and 30 min) and including various products of the Fe0-persulfate reaction at T=0 min (Fe2+, Fe3+, and SO42−). Results showed that when dioxane was spiked into the reaction at 30 min, no degradation occurred; this is in stark contrast to the 60% decrease observed when added at T = 0 min. Adding Fe2+ at the onset (T= 0 min) also severely halted the reaction and caused a plateau. This indicates that excess ferrous iron produced from the Fe0-persulfate reaction scavenges sulfate radicals and prevents further dioxane degradation. By limiting the release of Fe0 in a slow-release wax formulation, degradation plateaus were avoided and 100% removal of dioxane observed. By using 14C-labeled dioxane, we show that ~40% of the dioxane carbon is mineralized within 6 d. These data support the use of slow-release persulfate and zerovalent iron to treat dioxane-contaminated water.