Abstract
摘要:環境奈米科技之研究與應用正在蓬勃發展,然而奈米材料進入環境介質後,可能之性質變化、流布與宿命,甚至對於生態、環境與人體健康之可能影響,已逐漸引起國內外各界之關注。尤其於水體環境中,因各項水質化學因子之影響,人造奈米懸浮液體材料奈米微粒於水體環境中物化性質之轉變與其可能之流布與宿命仍待持續之研究與評估。目前人造奈米懸浮性材料顆粒之量測技術尚無一統一之標準方法,尤其在水介質中奈米懸浮性材料型態、粒徑與物化性質會因水質化學特性而有所轉變,所以建構一測量水介質中奈米懸浮性顆粒之檢測技術,並研討水質化學對於量測奈米顆粒之干擾,建立分析顆粒穩定性與親疏水特性之方法,將有助於分析奈米懸浮性材料之環境宿命,並可藉由此研究方法的建置探討人造懸浮性奈米顆粒之生態風險。奈米微粒在水中之分析技術是目前國際上奈米科技的重要議題與關鍵技術,所以本研究的主要目在於嘗試建立水體中奈米量測技術包含如何應用新穎之測量技術正確且有效地量測在水體介質中奈米微粒大小尺寸與數量,分析之準確性、重覆性及不確定性,以及奈米微粒經時之聚集與沈降特性。並且嘗試建立水中奈米微粒特性分析之技術,主要開發微粒之穩定程度與親疏特性分析方法。另外,探討水介質中酸鹼度、鹽類、水中組成等之干擾程度。同時蒐集最新國際上水環境介質中奈米微粒量測、轉換及宿命之資訊,綜合國內已有之資料,完成水體環境中奈米微粒之檢驗方法建立與探討水質參數對於奈米微粒在水介質中的轉換及宿命研究。探討水溶液介質中懸浮奈米微粒之採樣及保存條件,研討與整理利用離心、過濾與流力層析技術進行微粒量測前處理之可行性,嘗試分離非奈米級微粒後,利用動態光散射技術 (DLS) 檢測奈米顆粒之粒徑分佈,並輔以電子顯微鏡影像確認粒徑大小。依照環檢所公告之分析方法,加酸消化後利用感應耦合電漿原子發射光譜儀 (ICP-OES) 檢測元素種類與計算其顆粒濃度,帶回粒徑分佈曲線,建立出可於實際環境水體中定性與定量奈米微粒之分析技術。探討檢測方法之干擾,建立檢測方法之品質管制,界定檢測方法之精密度及準確度。並且研究奈米微粒之正辛醇水分配係數與細胞毒性試驗培養基中穩定懸浮奈米微粒之轉變。另外,探討水介質中酸鹼度、鹽類、水中組成等對懸浮奈米微粒轉換與沈降特性的影響,建立出分析奈米顆粒穩定特性之方法。蒐集國內外文獻與技術資料及各國初步管制草案,作成文獻回顧與整理,評估目前現有技術及未來發展。探討奈米微粒受國內各類環境水質之影響,評估可能之污染產業及現有廢水處理之效能
Abstract: We have studied the aggregation behaviors of commercial nanopowders in 2008, self-synthesized suspension nanoparticles in 2009 and two commercial nanoparticle suspensions in 2010. In this year, TiO2 and ZnO nanoparticles have been widely used so these two commercial nanoparticle suspensions were chosen as model nanoparticles to develop the analytical methodology and study the sedimentation behaviors under different aquatic conditions. The two commercial nanoparticles, TiO2 and ZnO, in aqueous suspensions were identified as nanoscale particles by a transmission electron microscopy (TEM) and dynamic light scattering (DLS). Zero point of charges (pHpzc) for TiO2 nanoparticles are 6.5 and 10.5, respectively. The DLS technology is cooperated with a pretreatment process including filtration, centrifugation, and settling to develop a methodology for the analysis of nanoparticles in the aquatic environment. Microscale SiO2 (micro-SiO2) particles were used to mimic general particles in the environment. The filtration pretreatment does not work well. For settling pretreatments, the mixture of micro-SiO2 and nanoscale polystyrene (nano-PS) can be settled for 2 h to removal the interference effect of large particles on DLS analysis and the recovery of nano-PS was 87%. By centrifugation, the mixture of micro-SiO2 and nano-PS was centrifuged with an angular speed of 4060 g for 2 min to removal SiO2 microparticles and the recovery of nano-PS was 74%. For nano-TiO2, the mixture of micro-SiO2 and nano-TiO2 was settled for 2 h to remove large particles and the recovery of nano-TiO2 was 88%. For the centrifugation of the mixture of micro-SiO2 and TiO2 (4060 g, 2 min), SiO2 particles can be removed and the recovery of nano-TiO2 was 81%. For the mixture of micro-SiO2 and nano-ZnO, the settling pretreatment cannot work. It can be centrifuged (4060 g, 2 min) to remove large particles on DLS analysis and the recovery of ZnO was 27%. All these results are confirmed by TEM. In addition, because the ZnO could be dissolved in water, the pretreated solution can be filtered with a centrifugal ultrafilter containing a membrane for 3kDa cutoff and then to calculate the real concentration of ZnO nanoparticles by the difference of total ZnO concentration. The combination of the centrifugation pretreatment before the DLS analysis and then confirmation by SEM or TEM is suggested to detect nanoparticles in the environment. For various aquatic parameters, the temperature in the range of 15~35℃did not significantly affect the stability of 1000 mg/L TiO2 (pH 3-4) and ZnO (pH 7-8). When the pH value in the range of pHpzc±1.2 for nano-TiO2 and pHpzc±0.6 for nano-ZnO at 25oC, obvious aggregation and sedimentation behaviors were found for these two nanoparticles in aqueous suspensions.
Keyword(s)
人造奈米二氧化鈦懸浮液
動態光散射技術
分析技術
團聚程度
穩定性
正辛醇水分配係數
engineered TiO2 nanoparticle
dynamic light scattering, DLS
analytical technology
aggregation
stability
n-octanol-water partition coefficient