跳到主要內容 :::

年度	111	專案性質	實驗性質
專案類別	研究專案	研究主題	整治
申請機構	國立台灣大學	申請系所	環境工程學研究所
專案主持人	林逸彬	職等/職稱	教授
專案中文名稱	以農業廢棄物製備生物炭活化過硫酸鹽去除地下水中含氯有機物之研究
中文關鍵字	生物炭, 過硫酸鹽, 含氯有機物, 地下水, 廢棄物減量
專案英文名稱	Removal of chlorinated organic pollutants in groundwater by agricultural waste-derived biochar activated persulfate
英文關鍵字	biochar, persulfate, chlorinated organic pollutants, groundwater, wastes reduction
執行金額	860,000元
執行期間	2022/7/1 至 2023/6/30
計畫中文摘要	以過單硫酸鹽或過二硫酸鹽作為氧化劑之過硫酸鹽高級氧化程序，因其低成本、高效率、易於傳輸等特性已被逐漸應用於地下水污染整治與現地化學氧化處理中。使用UV、微波、加熱、金屬氧化物以及含碳材料活化過硫酸鹽產生活性物質去除目標污染物為常見之活化方法。然而，高耗能、金屬溶出二次污染、製造成本高等問題，限制其實際應用能力。生物炭為一新興之環境整治材料，主要在缺氧或限氧條件下，熱裂解各種生質材料而得，已有文獻利用生物炭活化過硫酸鹽，以提升有機污染物降解的效率，然針對生物炭活化過硫酸鹽之表面活化機制仍有待釐清，且未普遍應用到實際工程領域中，亦缺少地下水水質環境影響之深入探討。本研究選擇稻殼為原料製成生物炭活化過硫酸鹽，評估對地下水常見之含氯有機污染物的去除能力。 研究結果顯示生物炭活化過單硫酸反應系統可有效降解五氯酚，而三氯乙烯僅可由生物炭表面吸附反應而被去除。五氯酚之去除速率隨著初始PMS增加、生物炭劑量提高及溶液初始pH下降而增加，在最佳參數條件下於反應90分鐘內達85%以上去除。五氯酚的去除受水中碳酸氫根離子的影響。綜合自由基捕捉劑實驗及電子順磁共振分析結果，反應系統會生成自由基與非自由基，但參與五氯酚降解反應的主要活性物質為單線態氧(1O2)。生物炭經重複使用測試，五氯酚去除效果隨使用次數的增加而下降，但可經由低溫鍛燒生物炭再生延長使用壽命。從成本效益的角度來看，將稻殼轉換為生物炭具正向價值，同時對解決廢棄物與減緩氣候變遷亦有助益。
計畫英文摘要	Persulfate-based advanced oxidation processes (AOPs), which are more cost-effective and less energy-intensive than conventional AOPs, have been explored for in-situ chemical oxidation to remove recalcitrant organic pollutants in groundwater. Persulfate-based AOPs can produce sulfate radicals, hydroxyl radicals, surface activated complex and singlet oxygen after efficient activation of peroxymonosulfate (PMS) or peroxydisulfate (PDS). Typical activation methods include UV, heat, microwaves and metal oxides. However, high energy consumption, metal leaching and high cost limit their practical applications in a large scale. Biochar is an emerging material produced by pyrolysis of biomass in the absence of oxygen or low oxygen and has been tested to activate persulfate to improve the removal of organic pollutants. However, the mechanism for persulfate activation by biochar is not clear, field application is rare and the influences of groundwater parameters on the process performance are not well evaluated. In this study, biochar prepared using rice husk as the raw materials is employed to activate persulfate for the removal of chlorinated organic pollutants. Preliminary data showed that pentachlorophenol (PCP) could be degraded in the biochar-activated persulfate system, while trichloroethylene (TCE) could only be removed by adsorption. The rate of PCP removal increased with the increasing PMS concentration and biochar loading, and decreasing solution pH, in which over 85% removal can be achieved in 90 minutes under the optimal reaction condition. The presence of HCO3̄ appeared to inhibit the removal of PCP. Based on the results of quenching experiments and electron paramagnetic resonance (EPR) analysis, it is concluded that radical and non-radical were involved in the biochar activated PMS system and singlet oxygen (1O2) was responsible for the degradation of PCP. Reusability tests showed that the performance of PCP removal decreased after four cycles but calcination regeneration was efficient for recovery of biochar to extend its longevity. Transforming rice husks into biochar can bring benefits for the treatment of agricultural waste and mitigation of climate change.