環保專案成果報告查詢系統

專案計畫編號	EPA-96--04-006
經費年度	096
計畫經費	2,500 千元
專案開始日期	2007/11/19
專案結束日期	2008/09/18
專案主持人	高志明
主辦單位	永續發展室(停用)
承辦人	林燕柔
執行單位	國立中山大學創新育成中心
專案分類	土壤及地下水
中文關鍵字	釋氧化劑物質, 過硫酸鹽, 地下水污染, 甲基第三丁基醚, 苯
英文關鍵字	oxidant releasing material, persulfate, contaminated groundwater, methyl tertiary-butyl ether, benzene
協同主持人
共同主持人	葉琮裕
計畫聯絡人	梁書豪
計畫聯絡電話
計畫聯絡信箱	d953030004@student.nsysu.edu.tw

中文摘要	本研究之目的即為研究發展過硫酸鹽氧化法結合含有緩慢釋放氧化劑物質之現地化學氧化反應牆(in situ oxidative wall)來現地處理石油碳氫化合物[以甲基第三丁基醚(methyl tertiary-butyl ether, MTBE)及苯(benzene)為目標污染物]所污染之地下水。計畫中主要包含釋氧化劑物質設計、過硫酸鹽批次氧化試驗及管柱試驗。計畫主要工作包含設計緩慢釋放氧化劑物質並研究其組成及釋放效率，以期用它長期釋放氧化劑。並以批次氧化實驗方式探討在不同環境及控制條件下[包含七組批次實驗，分別為不同過硫酸鹽濃度、不同亞鐵濃度、不同催化劑[如：轉爐石(basic oxygen furnace slag, BOF slag)、過硫酸鹽與MTBE及苯單獨共存(過硫酸鹽對MTBE及苯之選擇性)、初始pH值、還原性物質及現地地下水]，對MTBE及苯去除效率之影響，並利用管柱試驗評估利用釋氧化劑物質現地整治受MTBE及苯污染地下水之可行性。在釋氧化劑物質製備實驗之結果顯示，不論以批次實驗或全因素分析法結果皆指出，水泥及水為主要影響因子，而水泥與水之共同影響效應最大，其次為水泥，第三影響效應為水，而砂的效應值較低。累積釋放量最大且釋放速率最快之比例為1：0.16：0.5(水泥：砂：水)，且水泥及水含量比例為2：1時，其累積釋放量是最大的，且釋放速率也較快。在批次實驗方面，過硫酸鹽濃度越高，MTBE及苯去除所需時間越短。低劑量的亞鐵便足以活化過硫酸鹽。此外，MTBE及苯去除效率與亞鐵濃度成良好之線性關係，但亞鐵濃度若過高，將使亞鐵與污染物競爭硫酸根自由基，造成處理效率不佳。且亞鐵添加濃度與硫酸根生成量成良好之線性關係。轉爐石中所含之金屬物質具有催化效果，但氧化效率遠低於亞鐵，原因係由於同相催化優於異相催化。過硫酸鹽單獨存在下，室溫可對過硫酸鹽催化降解污染物。以污染物降解效率比較，相較於苯環，MTBE中醚鍵(C-O)屬飽和鍵，因此較難以被降解。酸性環境下，氫離子易催化過硫酸鹽產生硫酸根自由基，而鹼性環境下，氫氧根離子會消耗硫酸根自由基，造成氧化能力降低。現地地下水中之總有機碳(total organic carbon, TOC)對於MTBE及苯之處理效率並未有顯著之影響，其原因可能為過硫酸鹽較不傾向與自然有機物反應所致。研究結果顯示，在適當條件下，MTBE降解副產物第三丁基醛(tert-butyl formate, TBF)及第三丁基醇(tert-butyl alcohol, TBA)亦能有效被去除，並無殘留之問題。過硫酸鹽氧化法處理後，pH值過低為一需注意之問題。現地地下水雖具有一定之緩衝能力，但仍無法將pH控制於接近中性。未來可考慮將含水層土壤加入進行評估，如此除可提高系統緩衝能力外，亦可更進一步評估自然有機物對處理效率之影響。管柱試驗中當過硫酸鹽釋放劑量足夠時，MTBE及苯皆可完全降解，而當釋氧化劑釋放量衰減時，其降解效率逐漸降低。過硫酸鹽經亞鐵催化降解MTBE時，初期先產生TBF，而後進而被降解成TBA。污染物降解效率逐漸遲緩的原因除過硫酸鹽釋出濃度逐漸降低外，亞鐵離子的競爭也是降解效率降低原因之ㄧ。ORP可做為現地氧化劑氧化能力評估之重要指標。由於水泥中之Ca(OH)2會溶於水中形成緩衝，因此反應環境並無立刻成為強酸狀態。另外反應後之三價鐵離子則會與Ca(OH)2結合形成FeOH3沉澱。而導電度趨勢也與殘餘過硫酸鹽濃度及硫酸鹽濃度相同。經X-光粉末繞射儀(X-Ray Powder Diffractometer, XRD)分析探討後發現當亞鐵離子濃度不足時，其針鐵礦可能為提供異相催化。由掃描式電子顯微鏡(scanning electron microscope, SEM)發現釋氧化劑物質使用前後表面差異，使用前表面大致平滑。使用後觀察其表面發現許多不同大小之孔洞。利用能量分散分析儀定(Energy-Dispersive Spectroscope，EDS)性釋氧化劑物質表面元素，發現釋氧化劑物質表面有些許三價鐵沉澱，導致Fe比例提高。而釋氧化劑整治牆設計結果得知受MTBE污染之地下水(MTBE=10 mg/L)需要25口整治井及24口補強整治井應可有效降解。受苯污染之地下水(苯=10 mg/L)需要28口整治井即可有效降解。釋過硫酸鹽整治牆整治技術具備透水性整治牆技術之初設成本及操作成本低廉及現地化學氧化技術之整治期程短，適合應用於各種污染物。在考量成本及效能上，釋氧化劑整治牆極具競爭力，但目前仍缺乏實際應用案例，未來將朝模場或實場應用，以加強該技術之應用性。
中文關鍵字	釋氧化劑物質, 過硫酸鹽, 地下水污染, 甲基第三丁基醚, 苯

中文摘要

本研究之目的即為研究發展過硫酸鹽氧化法結合含有緩慢釋放氧化劑物質之現地化學氧化反應牆(in situ oxidative wall)來現地處理石油碳氫化合物[以甲基第三丁基醚(methyl tertiary-butyl ether, MTBE)及苯(benzene)為目標污染物]所污染之地下水。計畫中主要包含釋氧化劑物質設計、過硫酸鹽批次氧化試驗及管柱試驗。計畫主要工作包含設計緩慢釋放氧化劑物質並研究其組成及釋放效率，以期用它長期釋放氧化劑。並以批次氧化實驗方式探討在不同環境及控制條件下[包含七組批次實驗，分別為不同過硫酸鹽濃度、不同亞鐵濃度、不同催化劑[如：轉爐石(basic oxygen furnace slag, BOF slag)、過硫酸鹽與MTBE及苯單獨共存(過硫酸鹽對MTBE及苯之選擇性)、初始pH值、還原性物質及現地地下水]，對MTBE及苯去除效率之影響，並利用管柱試驗評估利用釋氧化劑物質現地整治受MTBE及苯污染地下水之可行性。在釋氧化劑物質製備實驗之結果顯示，不論以批次實驗或全因素分析法結果皆指出，水泥及水為主要影響因子，而水泥與水之共同影響效應最大，其次為水泥，第三影響效應為水，而砂的效應值較低。累積釋放量最大且釋放速率最快之比例為1：0.16：0.5(水泥：砂：水)，且水泥及水含量比例為2：1時，其累積釋放量是最大的，且釋放速率也較快。在批次實驗方面，過硫酸鹽濃度越高，MTBE及苯去除所需時間越短。低劑量的亞鐵便足以活化過硫酸鹽。此外，MTBE及苯去除效率與亞鐵濃度成良好之線性關係，但亞鐵濃度若過高，將使亞鐵與污染物競爭硫酸根自由基，造成處理效率不佳。且亞鐵添加濃度與硫酸根生成量成良好之線性關係。轉爐石中所含之金屬物質具有催化效果，但氧化效率遠低於亞鐵，原因係由於同相催化優於異相催化。過硫酸鹽單獨存在下，室溫可對過硫酸鹽催化降解污染物。以污染物降解效率比較，相較於苯環，MTBE中醚鍵(C-O)屬飽和鍵，因此較難以被降解。酸性環境下，氫離子易催化過硫酸鹽產生硫酸根自由基，而鹼性環境下，氫氧根離子會消耗硫酸根自由基，造成氧化能力降低。現地地下水中之總有機碳(total organic carbon, TOC)對於MTBE及苯之處理效率並未有顯著之影響，其原因可能為過硫酸鹽較不傾向與自然有機物反應所致。研究結果顯示，在適當條件下，MTBE降解副產物第三丁基醛(tert-butyl formate, TBF)及第三丁基醇(tert-butyl alcohol, TBA)亦能有效被去除，並無殘留之問題。過硫酸鹽氧化法處理後，pH值過低為一需注意之問題。現地地下水雖具有一定之緩衝能力，但仍無法將pH控制於接近中性。未來可考慮將含水層土壤加入進行評估，如此除可提高系統緩衝能力外，亦可更進一步評估自然有機物對處理效率之影響。管柱試驗中當過硫酸鹽釋放劑量足夠時，MTBE及苯皆可完全降解，而當釋氧化劑釋放量衰減時，其降解效率逐漸降低。過硫酸鹽經亞鐵催化降解MTBE時，初期先產生TBF，而後進而被降解成TBA。污染物降解效率逐漸遲緩的原因除過硫酸鹽釋出濃度逐漸降低外，亞鐵離子的競爭也是降解效率降低原因之ㄧ。ORP可做為現地氧化劑氧化能力評估之重要指標。由於水泥中之Ca(OH)2會溶於水中形成緩衝，因此反應環境並無立刻成為強酸狀態。另外反應後之三價鐵離子則會與Ca(OH)2結合形成FeOH3沉澱。而導電度趨勢也與殘餘過硫酸鹽濃度及硫酸鹽濃度相同。經X-光粉末繞射儀(X-Ray Powder Diffractometer, XRD)分析探討後發現當亞鐵離子濃度不足時，其針鐵礦可能為提供異相催化。由掃描式電子顯微鏡(scanning electron microscope, SEM)發現釋氧化劑物質使用前後表面差異，使用前表面大致平滑。使用後觀察其表面發現許多不同大小之孔洞。利用能量分散分析儀定(Energy-Dispersive Spectroscope，EDS)性釋氧化劑物質表面元素，發現釋氧化劑物質表面有些許三價鐵沉澱，導致Fe比例提高。而釋氧化劑整治牆設計結果得知受MTBE污染之地下水(MTBE=10 mg/L)需要25口整治井及24口補強整治井應可有效降解。受苯污染之地下水(苯=10 mg/L)需要28口整治井即可有效降解。釋過硫酸鹽整治牆整治技術具備透水性整治牆技術之初設成本及操作成本低廉及現地化學氧化技術之整治期程短，適合應用於各種污染物。在考量成本及效能上，釋氧化劑整治牆極具競爭力，但目前仍缺乏實際應用案例，未來將朝模場或實場應用，以加強該技術之應用性。

中文關鍵字

釋氧化劑物質, 過硫酸鹽, 地下水污染, 甲基第三丁基醚, 苯

類型	檔名	檔案大小	說明	最新版公開日期
期末報告	96育成期末報告(定稿).pdf	3MB	[期末報告]公開完整版	2009/3/1 上午 12:00:00

摘要	Contamination of soil/groundwater supplies by gasoline and other petroleum-derived hydrocarbons released from underground storage tanks (USTs) is a serious and widespread environmental problem. Corrosion, ground movement, and poor sealing can cause leaks in tanks and associated piping. Petroleum hydrocarbons contain methyl tertiary-butyl ether (MTBE) (a fuel oxygenate), benzene, toluene, ethylbenzene, and xylene isomers (BTEX), the major components of gasoline, which are hazardous substances regulated by many nations. MTBE possesses all the characteristics of a persistent compound in the subsurface: high solubility, low volatility, low sediment sorption, and resistance to biodegradation. Among BTEX, benzene is a carcinogenic compound and is more recalcitrant under anaerobic conditions. Thus, MTBE and benzene are selected as the target compounds in this study. One cost-effective approach for the remediation of the chlorinated-solvent and petroleum products contaminated aquifers is the installation of permeable reactive zones or barriers within aquifers. As contaminated groundwater moves through the emplaced reactive zones, the contaminants are removed, and uncontaminated groundwater emerges from the downgradient side of the reactive zones. The objective of this proposed study is to assess the potential of using a passive in situ oxidation barrier system. This passive active barrier system has advantages over conventional systems including less maintenance, cost-effectiveness, no above-ground facilities, no groundwater pumping and reinjection, and groundwater remediation in situ. The oxidation barrier system included a persulfate-releasing barrier, which contains persulfate-releasing materials. The slow-released persulfate would oxidize MTBE and benzene in aquifer. The persulfate-releasing materials would release persulfate when contacts with groundwater, thus oxidizes the MTBE and benzene. In the first part of this study, bench scale experiment was also performed to produce the persulfate-releasing materials high persulfate-releasing rate. The components of the persulfate-releasing materials and optimal concentrations of those components were determined in this study. Results indicate that the highest persulfate releasing rate can be obtained when the mass ratio of cement/sand/water was 1/0.16/0.5. Batch experiments were also performed to test the feasibility of using persulfate as the oxidants for MTBE and benzene oxidation. Several oxidation conditions including the concentrations of contaminants and oxidants, appearance of ferric and ferrous irons, appearance of hydrocarbon peroxide, various ambient pH values, and sulfate concentrations were evaluated. Results indicate that the most effective MTBE and benzene removal rates were observed when the molar ratio of MTBE/Na2S2O8/Fe2+ and benzene/Na2S2O8/Fe2+ were in the range of 1/50/31 to 1/500/31 and 1/50/31 to 1/100/31, respectively. Moreover, higher degradation rates of MTBE and benzene can be obtained with higher persulfate concentrations. Results also show that degradation rates of MTBE and benzene correlated with the amount of Fe(II) addition. However, only small amount of Fe(II) was required to activate the oxidation. Extra Fe(II) would cause the decrease the oxidation rates due to the reaction of sulfate and Fe(II). Results also reveal that the produced oxidation byproducts of MTBE, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), can also be degraded completely. Result obtained from the persulfate-releasing materials test and bench-scale were used for the design and operation of the following column experiments. Results from the column experiment indicate that approximately 87% of MTBE and 99% of benzene could be removed during the early persulfate-releasing stage. However, the removal efficiencies for MTBE and benzene dropped to approximately 38% and 54%, respectively, during the latter part of the releasing period. Results reveal that TBF and TBA, byproducts of MTBE, were observed. Complete degradation of TBF and TBA were also observed in this study. Results from this study suggest that extra Fe(II) would cause the decrease in oxidation rates due to the reaction of sulfate with Fe(II). Results show that the parameters, which would affect the oxidation rate include persulfate concentration, oxidant reduction potential (ORP), conductivity, sulfate concentration, and contaminant concentration. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate MTBE and other petroleum-hydrocarbon contaminated aquifers. Knowledge obtained from this study will aid in designing a persulfate oxidation system for site remediation.
英文關鍵字	oxidant releasing material, persulfate, contaminated groundwater, methyl tertiary-butyl ether, benzene

摘要

Contamination of soil/groundwater supplies by gasoline and other petroleum-derived hydrocarbons released from underground storage tanks (USTs) is a serious and widespread environmental problem. Corrosion, ground movement, and poor sealing can cause leaks in tanks and associated piping. Petroleum hydrocarbons contain methyl tertiary-butyl ether (MTBE) (a fuel oxygenate), benzene, toluene, ethylbenzene, and xylene isomers (BTEX), the major components of gasoline, which are hazardous substances regulated by many nations. MTBE possesses all the characteristics of a persistent compound in the subsurface: high solubility, low volatility, low sediment sorption, and resistance to biodegradation. Among BTEX, benzene is a carcinogenic compound and is more recalcitrant under anaerobic conditions. Thus, MTBE and benzene are selected as the target compounds in this study. One cost-effective approach for the remediation of the chlorinated-solvent and petroleum products contaminated aquifers is the installation of permeable reactive zones or barriers within aquifers. As contaminated groundwater moves through the emplaced reactive zones, the contaminants are removed, and uncontaminated groundwater emerges from the downgradient side of the reactive zones. The objective of this proposed study is to assess the potential of using a passive in situ oxidation barrier system. This passive active barrier system has advantages over conventional systems including less maintenance, cost-effectiveness, no above-ground facilities, no groundwater pumping and reinjection, and groundwater remediation in situ. The oxidation barrier system included a persulfate-releasing barrier, which contains persulfate-releasing materials. The slow-released persulfate would oxidize MTBE and benzene in aquifer. The persulfate-releasing materials would release persulfate when contacts with groundwater, thus oxidizes the MTBE and benzene. In the first part of this study, bench scale experiment was also performed to produce the persulfate-releasing materials high persulfate-releasing rate. The components of the persulfate-releasing materials and optimal concentrations of those components were determined in this study. Results indicate that the highest persulfate releasing rate can be obtained when the mass ratio of cement/sand/water was 1/0.16/0.5. Batch experiments were also performed to test the feasibility of using persulfate as the oxidants for MTBE and benzene oxidation. Several oxidation conditions including the concentrations of contaminants and oxidants, appearance of ferric and ferrous irons, appearance of hydrocarbon peroxide, various ambient pH values, and sulfate concentrations were evaluated. Results indicate that the most effective MTBE and benzene removal rates were observed when the molar ratio of MTBE/Na2S2O8/Fe2+ and benzene/Na2S2O8/Fe2+ were in the range of 1/50/31 to 1/500/31 and 1/50/31 to 1/100/31, respectively. Moreover, higher degradation rates of MTBE and benzene can be obtained with higher persulfate concentrations. Results also show that degradation rates of MTBE and benzene correlated with the amount of Fe(II) addition. However, only small amount of Fe(II) was required to activate the oxidation. Extra Fe(II) would cause the decrease the oxidation rates due to the reaction of sulfate and Fe(II). Results also reveal that the produced oxidation byproducts of MTBE, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), can also be degraded completely. Result obtained from the persulfate-releasing materials test and bench-scale were used for the design and operation of the following column experiments. Results from the column experiment indicate that approximately 87% of MTBE and 99% of benzene could be removed during the early persulfate-releasing stage. However, the removal efficiencies for MTBE and benzene dropped to approximately 38% and 54%, respectively, during the latter part of the releasing period. Results reveal that TBF and TBA, byproducts of MTBE, were observed. Complete degradation of TBF and TBA were also observed in this study. Results from this study suggest that extra Fe(II) would cause the decrease in oxidation rates due to the reaction of sulfate with Fe(II). Results show that the parameters, which would affect the oxidation rate include persulfate concentration, oxidant reduction potential (ORP), conductivity, sulfate concentration, and contaminant concentration. The proposed treatment scheme would be expected to provide a more cost-effective alternative to remediate MTBE and other petroleum-hydrocarbon contaminated aquifers. Knowledge obtained from this study will aid in designing a persulfate oxidation system for site remediation.

英文關鍵字

oxidant releasing material, persulfate, contaminated groundwater, methyl tertiary-butyl ether, benzene