Synthesis of Dense Non Aqueous Suspension of Nano-Scale Zero Valent Iron
Date Issued
2011
Date
2011
Author(s)
Lin, Hong-Wei
Abstract
In recent years, suspended colloidal zero valent iron nanoparticles have been applied to the dechlorination of aqueous chlorinated solvents in polluted groundwater. However, due that nonaqueous chlorinated solvents and water are immiscible, nonaqueous chlorinated solvents could not react with aqueous colloidal zero valent iron nanoparticles. To overcome the drawback, eco-friendly dense nonaqueous suspensions of nano-scale zero-valent iron (DNAPNZVI) were developed.
In this study, dimethyl carbonate (DMC) was chosen as the surface-modified nano zero valent iron’s carrying liquid. DMC has low toxicity, high biodegradability, immiscibility with water, denser density than water and low viscosity, which meets the criteria of the carrying liquid.
Octadecyl phosphate, cetyltrimethylammonium bromide or poly methyl methacrylate was used to modify the surfaces of commercial nano zero valent iron (NZVI). The results of demonstrated that three kinds of DNAPNZVI were easily miscible with chlorinated solvent. In addition, NZVI modified with CTAB or PMMA, were stably suspended in DMC. The mean particle size ranged from 50 to 100 nm, surface area was 16.54 m2/g and the content of iron was 83-85 wt%.
The results of dechlorination experiment for 262 mg/L TCE in DMC-saturated water showed that there was not TCE degradation found during ten hours with PMMA/Fe0.
DNAPNZVI, at the concentration of 10 Fe g/L and with a specific gravity of 1.073 was injected into with grain size from 200 to 250 μm saturated quartz sand column. The result of experiment revealed that the capillary force of the oil-water system in saturated quartz sand column to be overcome was 1050 N/m2 by PMMA/Fe0 was 1050 N/m2 and 1788 N/m2 for CTAB/Fe0.
Subjects
surface modification
poly methyl methacrylate
dense nonaqueous suspension of Nano Scale zero valent iron
dimethyl carbonate
Type
thesis
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