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標題: 奈米級零價鐵結合過氧化氫與Fenton試劑處理含PAHs污染土壤
Using Nano Scale Zero-Valent Iron with Hydrogen Peroxide and Fenton Reagents for Treatment of PAHs Contaminated Soil
作者: 謝文彬
Hsieh, Wen-Pin
關鍵字: PAHs
Zero-valent iron
Nano scale synthesizes iron
Mechanical ground Nano scale iron
Soil remediation

出版社: 土壤環境科學系
摘要: Abstract The sites contaminated with recalcitrant organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), are colossal environmental problems. The PAHs are a group of compounds rearing with multiple benzene rings, which are relatively ubiquitous as well as hardly be degraded by microorganics found in the heavier fractions of petroleum, have been proven to be carcinogenic by some researchers. There are 16 of PAHs listed in the US EPA priority pollutants due to their toxic and mutagenic nature. Thus, the innovative remediation technologies to remove PAHs of the contaminated sites have to be uncovered very urgently. The aims of this study are compared with three kinds of chemical disposal method:(1)Fenton reaction (hydrogen peroxide+ferrous ), and(2)Nano scale Zero-Valent Iron and (3)Fenton-like reaction(Nano scale Zero-Valent Iron+hydrogen peroxide). Fragment pyrene in the spiked soil was prepared. The experimental condition were determined such as reaction time, hydrogen peroxide and ferrous concentration, preparation method of nano scale Zero-Valent iron prepare method (synthesize and mechanical ground), iron particle size and dosage. The experimental results demonstrated that Fenton''s reactions efficiently decomposed the target compound. The optimum experimental conditions resulted in 85% removal efficiency of pyrene while operational conditions were concentrations of ferrous and hydrogen peroxide of 24.7 mM and 206 mM, respectively. Ultimately, The molar ratio was deduced as pyrene : ferrous : hydrogen peroxide = 1: 50 : 416 under the optimum conditions. Treatment cost about 0.307 NT $/kg soil。 Nano scale synthesized iron particle size is in the range of 50~80 nm with surface area of 141±3 m2 g-1. Nano scale mechanical ground iron particle size is in the range of 100~250 nm with surface area of 21±10 m2 g-1. Micro scale Zero-Valent iron particle size is in the range of 45 μm with surface area of 1.821 m2 g-1. The sequence for the removal efficiency of pyrene was nano scale synthesized Zero-Valent iron of 80%>mechanical ground nano scale Zero-Valent iron of 60%>micro scale Zero-Valent iron of 11%. The Nano scale synthesized Zero-Valent iron is fast about 60 min. and washed Zero-Valent iron by 0.1 M HCl acid, the removal efficiency to nearly increases to 2.5 times. Therefore, the results show that nanoscale iron particle can be recovered to reuse for the reduction of pyrene. The treatment cost is about 0.495 NT $/kg soil。 In Fenton-like reaction, nano scale Zero-Valent iron added with hydrogen peroxide, the addition of hydrogen peroxide in reaction system increases the removal efficiency of pyrene by 20%. Nevertheless, Nano scale Zero-Valent Iron dosage is 0.3 g and hydrogen peroxide 206 mM , removal efficiency of Pyrene 93%. This indicates that Fenton-like reaction can degrade efficiently to decompose the target compound. The molar ratio was deduced as pyrene : nano scale iron : hydrogen peroxide = 1: 9.2 : 416 under the optimum conditions. treatment cost is about 0.357 NT $/kg soil. In addition, nano scale iron is even smaller than the soil pores. While poured into underground water may distribute in the soil pores to move and degrade pollutant. Therefore, it is optimistically predictable and encouraged that the environmental applications for the further pilot and field contamination assessment by this technology are expectable promptly in the near future. Keyword:PAHs, Pyrene, Zero-valent iron, Nano scale synthesizes iron, Mechanical ground Nano scale iron , Fenton, Fenton-like, Soil remediation
摘要 土壤中受多環芳香烴化合物(PAHs)污染問題已愈受重視,PAHs主要源於空氣中燃燒及車輛廢氣排放等PAHs沉降;或是油品洩漏於土壤與地下水中。PAHs已被證實超過30種及好幾百種衍生物具有致癌性與致突變性,已成目前所知環境中最大量具致癌性單一化學物種。此外,其為聯合國歐洲經濟委員會管制之十六種持久性有機污染物之一,有鑑於此發展快速與有效之整治方法實為當務之急,因此,本研究目的係以三種化學處理方式,(1) Fenton(亞鐵離子加過氧化氫)法,(2) 奈米級零價鐵金屬(1-100 nm),(3) Fenton-like(奈米鐵加過氧化氫)法,處理實驗室配製模擬受PAHs中含四苯環之Pyrene污染土壤,並探討採用奈米級零價鐵結合過氧化氫與Fenton法對PAHs之整治成效,探討不同操作條件下,包括過氧化氫濃度、亞鐵離子濃度、鐵粉粒徑、鐵粉添加量、奈米級零價鐵製備方式、處理時間、零價鐵表面處理與再生試驗…等,對於處理效率之效應。 試驗結果發現,Fenton試劑起始反應非常快速,約30分鐘反應即完成,當H2O2為206 mM與Fe2+為24.7 mM,目標物去除率可達85%,因此可知Fenton反應可有效降解目標污染物。並且由此可求得最佳操作條件之莫爾濃度關係為Pyrene:亞鐵離子:過氧化氫為1:50:416,操作費用約0.307 NT $/ kg soil。 奈米級零價鐵法,試驗中化學合成法之奈米鐵粒徑範圍50~80 nm,表面積為141±3 m2 g-1,機械研磨法粒徑範圍為100~250 nm,表面積為21±10 m2 g-1。微米級零價鐵粒徑約45 μm,表面積為1.821 m2 g-1(此分析結果皆經由酸洗前處理)。去除Pyrene效率以化學合成奈米級零價鐵80%>機械研磨奈米級鐵60%>微米級鐵11%。此外,奈米級零價鐵起始反應非常快速約60分鐘反應即完成,而奈米級零價鐵表面經由酸洗後,去除效率約增加2.5倍,此試驗結果可做為傳統微米級零價鐵之再生與去除表面氧化物之參考,當奈米級零價鐵去除Pyrene達80%,操作費用約0.495 NT $/ kg soil。 Fenton-like效應,試驗結果可以發現,奈米級鐵加入過氧化氫,起始反應非常快速約30分鐘反應即完成,去除Pyrene效率約比未加入過氧化氫增加20%,當奈米級鐵劑量為0.3 g,H2O2為206 mM ,Pyrene去除效率約達93%以上,因此可知Fenton-like反應可有效降解目標污染物。並且由此可求得最佳操作條件之莫爾濃度關係為Pyrene:亞鐵離子:過氧化氫為1:9.2:416,操作費用約0.357 NT $/ kg soil。此外,本試驗中奈米零價鐵由於粒徑比土壤孔隙還小,所以可利用此特性注入受污染之土壤中,隨著地下水流佈於土壤孔隙中移動,或添加注入過氧化氫於土壤中有助於奈米級零價鐵之移動,並且更有助於反應,以達到加成之去除污染物效率,此項結果有作為現地污染物整治之應用參考。 關鍵字:多環芳香烴化合物,芘,微米級零價鐵,化學合成奈米級零價鐵,機械研磨奈米級零價鐵,Fenton反應,Fenton-like反應,土壤污染整治
Appears in Collections:土壤環境科學系



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