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年度	110	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	國立臺灣大學	申請系所	地質科學系
專案主持人	劉雅瑄	職等/職稱	教授
專案中文名稱	農業廢棄物高值化於選擇性吸附地下水中五價砷之研究
中文關鍵字	五價砷、選擇性吸附、農業廢棄物
專案英文名稱	Selective adsorption of Arsenate (V) in groundwater using high-value utilization of agricultural waste
英文關鍵字	Arsenate (V), selective adsorption, agricultural waste
執行金額	880,000元
執行期間	2021/1/1 至 2021/12/31
計畫中文摘要	全球地下水普遍存在砷污染問題，而現行技術應用於處理含砷地下水皆受限於砷的低選擇性，砷的去除已成為實務整治上的問題。本研究以廢菇包介質(spent mushroom substrate, SMS)作為基材，透過碳化與活化程序製成菇包生物炭(SMS biochar, SMSB)。隨後利用硝酸與四亞乙基五胺(tetraethylenepentamine, TEPA)以迴流嫁接法分別進行酸化修飾與胺基修飾，進而在菇包生物炭上批覆對五價砷具有吸附選擇性之胺官能基團(amine group)，促使五價砷的吸附容量提升。製備而成之菇包生物炭複合材料(SMSB-TEPA)將藉由比表面積及孔徑分析儀、X射線光電子能譜儀、場發射掃描電子顯微鏡與傅立葉轉換紅外線光譜儀進行物化特性分析，為掌握複合材料之最佳製備條件。研究成果顯示，控制活化程序可使SMSB的比表面積提升至459.8 m2/g，高於初始的比表面積約3.4倍。值得一提的是，經由酸化修飾後的菇包生物炭觀察到羧基(−COOH)之鍵結，其有利於胺基修飾階段羥基(−OH)與胺基(−NH2)的置換反應。於胺基修飾後，可明顯觀察到−NH與−NH2二者胺基的特徵峰，而−COOH及−OH的特徵峰則不顯著，說明−OH與−NH2的置換成功製成菇包生物炭之高值化複合材料。SMSB-TEPA複合材料表面所披覆之TEPA可提供大量的胺基活性點位與優異的吸附親合性，有助於增進五價砷的吸附效能。相比於SMSB材料的吸附容量與吸附速率，SMSB-TEPA複合材料對五價砷的吸附容量提高將近3倍、吸附速率提高約2倍，其結果可能歸因於TEPA吸附五價砷的機制，SMSB-TEPA複合材料表面的TEPA可通過質子化的過程獲得正電荷，可促使帶負電的五價砷物種以靜電吸引的方式去除。整體而言，研究計畫已完成SMSB-TEPA複合材料於五價砷去除之可行性研究，並對於處理含砷污染地下水的技術需求具有實務應用價值與發展潛力，實符合廢棄物高值化、資源循環再利用之新穎技術。
計畫英文摘要	Arsenic contamination in groundwater has existed for decades. In Southeast Asia countries, the issue of arsenic contaminations in both the drinking water and groundwater has attracted a lot of attention due to its toxic and carcinogenic nature. Nowadays, the selective removal methods for arsenic have been emphasized. Biochar (BC) is one of the materials that have been widely discussed sustainable remediation for arsenic removal, which recognized as an emerging technology. The BC can be enhanced through the high-quality value utilization of agricultural waste such as surface activation by thermal pyrolysis and surface modification. In this study, the BC was made by spent mushroom substrate (SMS). The SMS biochar (SMSB) is prepared through the physical activation of carbon dioxide. The mechanism of selective adsorption was investigated to enhance the selective adsorption of arsenate on high-quality BC. The objectives of this study are using high-value utilization of agricultural waste for selective adsorption of Arsenate in groundwater. The surface characteristics were investigating by BET, XPS, SEM and EDS method. The results were used to evaluate the selective adsorption of arsenate by high-value utilization methods. The surface properties of the material for further subsequent evaluation of selective adsorption of arsenate performance. The results showed that the activation process could increase the specific surface area of SMSB to 459.8 m2/g, which is about 3.4 times higher than that of carbonized SMSB (without activation). It is worth mentioning that the bonding of the carboxyl group (−COOH) was observed in the SMSB after the acidification modification, which facilitated the replacement reaction of the hydroxyl group (−OH) with the amine group (−NH2) in the amine modification. After the amine modification, the peak of the amine group (−NH and −NH2) was clearly observed, while the peaks of −COOH and −OH were not significant. The results indicate that the replacement of −OH and −NH2 is successful, resulting in a high-value SMSB composite material. Notably, the TEPA coating on the surface of SMSB-TEPA composite provides a large amount of active sites of amine groups and excellent affinity for adsorption, based active sites and excellent adsorption affinity, which can help to improve the adsorption performance of As(V). Compared with SMSB material, the adsorption capacity of SMSB-TEPA composite material for As(V) is increased nearly three-fold and the adsorption rate is increased about two-fold. The results are attributed to the mechanism of As(V) adsorption by TEPA. The TEPA could obtain a positive charge by protonation and subsequently remove the negatively charged As(V) species by electrostatic attraction. Overall, the research project has completed the feasibility study of SMSB-TEPA composite material for As(V) removal. This study has practical application value and development potential for the treatment of arsenic-contaminated groundwater, which is in line with the novel technology of high-value waste and resource recycling.