| Summary: | 碩士 === 弘光科技大學 === 環境工程研究所 === 98 === Abstract
The polycyclic aromatic hydrocarbons (PAHs）are majorly produced through human daily activities. The source of PAHs in soil originates from atmospheric deposition by incomplete combustion of organic matter or exhaust emission of automobiles. Some PAHs have proven to be carcinogenic and mutagenic. The objective of this study was to propose soil remediation of pyrene (4-benzene ring PAHs) and 6 mixed PAHs by nano zero valent iron (Fe0, nZVI) and nano bimetal iron with Nickel or Zinc (n-Fe/Ni, n-Fe/Zn). From the results, the reaction time was set in 30 min because there were no significant change of pyrene removal after 30 min. Adding nZVI, n-Fe/Zn and n-Fe/Ni can remove pyrene and 6 mixed PAHs rapidly and effectively in 30 minutes. While the initial pyrene concentration of 100 mg/kg in soil, adding nZVI, n-Fe/Ni and n-Fe/Zn of 0.15g resulting pyrene removal from soil A was 60, 60 and 52%, respectively that soil B was similar to 42%. Increasing dose to 0.6g, pyrene removal from soil A increased to 69,100 and 72%, soil B obtained 58, 83 and 61%, respectively Therefore pyrene removal was improved by increasing the dose of nano metals while n-Fe/Ni＞n-Fe/Zn＞nZVI and soil A＞B. The pH of soil A and B was increased from 4.5 to 7.9 and 7.3 to 8.1~8.7, respectively. The (Oxidation Reduction Potential) ORP of soil A was decrease from +400 mV to -600 mV reaching reduction while ORP of soil B was similar to soil A.
The pyrene removal were significantly reduced when increasing the initial concentration from 100, 500 to 1000 mg/kg by adding 0.3g of nZVI, n-Fe/Zn and n-Fe/Ni. The pyrene removal of soil A was from of 60, 85 and 63% reducing to 39, 54 and 49% while the initial pyrene concentration increasing from 100 to 1000 mg/kg in soil. Similar to soil B, pyrene removal from 52, 71 and 54% reducing to 19, 43 and 42% respectively. Thus, the certain dose of nano particles addition significantly enhanced the pyrene removal obtaining n-Fe/Ni＞n-Fe/Zn＞nZVI. Morerover pH of soil A and B was from 8 and 8.5, respectively and ORP was -600 mV and -200 ~ -600 mV. Therefore removal of 6 mixed PAHs were improved by increasing the dose of nano metals while n-Fe/Ni＞nZVI and soil A＞B. The pH of soil A and B was 7.8 and 8, respectively and ORP was -600 and -650 mV.
From FTIR identification, the C = C in aromatic rings may be degraded to alkenes C = C by adding nZVI and n-Fe/Ni that is biogradable by soil microorganisms. Therefore nZVI or bimetal n-Fe/Ni or n-Fe/Zn addition are feasible for soil remediation of pyrene and 6 mixed PAHs.
Keywords：PAHs, nano zero valent iron, nZVI, bimeatal, Fe/Ni, Fe/Zn
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