环境修复
环境化学
过硫酸盐
土壤污染
污染
化学
土壤修复
环境科学
土壤水分
有机化学
土壤科学
生态学
生物
催化作用
作者
Fernándo López Pardo,Aurora Santos,Alfredo Salvador
标识
DOI:10.1016/j.scitotenv.2016.04.197
摘要
Remediation of contaminated soils under flow-through conditions is an issue of great interest since it provides a better approach to real case applications than batch experiments. In this work, a column filled with soil, artificially spiked and aged for three months with Phenanthrene (PHE), Anthracene (ANT), Pyrene (PYR) and Benzo(a)pyrene (BaP), was treated for 25 days with persulfate (PS) activated by Fe3 + and nanoparticles of zerovalent iron (nZVI). Effects of type of iron fed into the column (Fe3 + or nZVI) and nZVI concentration were studied. PS inlet concentration was 0.2 mmol cm− 3 and residence time in the column was close to 1.72 days. Iron, PS and polycyclic aromatic hydrocarbons (PAHs) concentration, as well as pH, were monitored during treatment. Concentration profiles of iron and PAHs were observed along the column, with higher iron concentrations and higher PAHs removal efficiencies in the closest sections to the column entrance. BaP and ANT were completely depleted regardless the conditions used, but PHE and PYR showed higher resistance to oxidation, achieving near a 90% removal in the closest sections to the injection source in all runs, but decreasing significantly with column length. Besides, natural degradation of ANT resulted in the formation 9.10-anthraquinone (ATQ), an oxy-PAH which showed higher resistance than PHE and PYR. Although higher PAHs removal efficiencies were achieved when nZVI was used as activator, only a moderate improvement was noticed when the highest concentration of nZVI was used as a consequence of radical scavenging by an excess of Fe2 +. Finally, a kinetic model based on runs performed in batch, from a previous work, was able to predict the experimental average concentrations of PAHs in the column when Fe3 + was used as activator.
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