環保專案成果報告查詢系統

專案計畫編號	EPA-100-U1U1-02-102
經費年度	100
計畫經費	1,800 千元
專案開始日期	2011/05/03
專案結束日期	2011/12/31
專案主持人	施養信
主辦單位	永續發展室(停用)
承辦人	蘇鈺珊
執行單位	台灣大學農化系
專案分類	水質保護
中文關鍵字	奈米微粒懸浮液;聚集;沉降
英文關鍵字	nanoparticle suspension;aggregation;sedimentation
協同主持人
共同主持人	董瑞安
計畫聯絡人	施養信
計畫聯絡電話	02-33669442#
計畫聯絡信箱	yhs@ntu.edu.tw

中文摘要	由於二氧化鈦 (TiO2) 與氧化鋅 (ZnO) 奈米微粒(nanoparticles, NPs)已廣泛地在使用，所以今年針對此兩商用奈米懸浮液作聚集與沉降特性之探討，並探討建立初步分析水體中奈米顆粒之方法。本研究採用動態光散射儀(dynamic light scattering, DLS)，探討過濾、離心及沉降三種前處理流程。離心4060 G 2分鐘，可有效將大顆粒移除，皆有74%~87%的NPs回收率。水體中奈米顆粒之方法，建議結合離心分離後，以DLS量測粒徑後消化測顆粒總濃度則可計算隨粒徑分佈之濃度，並搭配電子顯微鏡作確認。另外，對於會溶解之NPs，在測總濃度後，再用超過濾膜，檢測溶解濃度後扣除，則可定量NPs濃度。在聚集與沉降實驗中，TiO2與ZnO分別於10 mg/L至1 g/L濃度及100 mg/L至1 g/L可維持奈米大小，並可長時間保持穩定，於此實驗中採用100 mg/L進行實驗。在15~35℃範圍下，溫度對顆粒粒徑與沉降之影響不明顯。TiO2與ZnO之水中酸鹼值(pH值)在接近等電點 (pHpzc 6.0 ±0.7 與pHpzc 10.3±0.6) 有明顯的粒徑變大與沉澱現象。奈米懸浮液皆隨著離子強度增加使絮聚現象更趨明顯，TiO2與ZnO奈米懸浮液之NaCl的臨界聚集濃度（critical aggregation concentration, CAC）分別為100 meq/L與10 meq/L，Na2SO4的CAC分別為1.5 meq/L與0.2 meq/L。因陰離子電荷可壓縮表面帶正電荷之奈米顆粒之電雙層，進而促使奈米顆粒聚集沉降。二價陰離子會較一價陰離子更強烈壓縮電雙層，而使之聚集，DLVO理論計算之結果也相符合。當腐植酸(humic acid, HA)濃度使顆粒表面電位接近等電點時，較易聚集與沉降。 NaCl、pH與HA交互作用下，TiO2以統計分析可觀察出於聚集速率方面，HA濃度有顯著影響；於沉降速率，則為pH。當Na2SO4、pH與HA交互作用下，於聚集速率，pH與HA有顯著影響；於沉降速率亦同，且pH與HA間之交互作用亦重要。於ZnO奈米懸浮液中，NaCl、pH與HA交互作用下，HA濃度對於聚集與沉降速率有顯著影響，pH與HA之交互作用對於沉降速率之影響亦重要。當Na2SO4、pH與HA交互作用下於聚集速率方面，HA濃度有顯著影響且pH與HA之間之交互作用亦重要；於沉降速率中各因子間之交互作用均無顯著影響。
中文關鍵字	奈米微粒懸浮液;聚集;沉降

中文摘要

由於二氧化鈦 (TiO2) 與氧化鋅 (ZnO) 奈米微粒(nanoparticles, NPs)已廣泛地在使用，所以今年針對此兩商用奈米懸浮液作聚集與沉降特性之探討，並探討建立初步分析水體中奈米顆粒之方法。本研究採用動態光散射儀(dynamic light scattering, DLS)，探討過濾、離心及沉降三種前處理流程。離心4060 G 2分鐘，可有效將大顆粒移除，皆有74%~87%的NPs回收率。水體中奈米顆粒之方法，建議結合離心分離後，以DLS量測粒徑後消化測顆粒總濃度則可計算隨粒徑分佈之濃度，並搭配電子顯微鏡作確認。另外，對於會溶解之NPs，在測總濃度後，再用超過濾膜，檢測溶解濃度後扣除，則可定量NPs濃度。在聚集與沉降實驗中，TiO2與ZnO分別於10 mg/L至1 g/L濃度及100 mg/L至1 g/L可維持奈米大小，並可長時間保持穩定，於此實驗中採用100 mg/L進行實驗。在15~35℃範圍下，溫度對顆粒粒徑與沉降之影響不明顯。TiO2與ZnO之水中酸鹼值(pH值)在接近等電點 (pHpzc 6.0 ±0.7 與pHpzc 10.3±0.6) 有明顯的粒徑變大與沉澱現象。奈米懸浮液皆隨著離子強度增加使絮聚現象更趨明顯，TiO2與ZnO奈米懸浮液之NaCl的臨界聚集濃度（critical aggregation concentration, CAC）分別為100 meq/L與10 meq/L，Na2SO4的CAC分別為1.5 meq/L與0.2 meq/L。因陰離子電荷可壓縮表面帶正電荷之奈米顆粒之電雙層，進而促使奈米顆粒聚集沉降。二價陰離子會較一價陰離子更強烈壓縮電雙層，而使之聚集，DLVO理論計算之結果也相符合。當腐植酸(humic acid, HA)濃度使顆粒表面電位接近等電點時，較易聚集與沉降。 NaCl、pH與HA交互作用下，TiO2以統計分析可觀察出於聚集速率方面，HA濃度有顯著影響；於沉降速率，則為pH。當Na2SO4、pH與HA交互作用下，於聚集速率，pH與HA有顯著影響；於沉降速率亦同，且pH與HA間之交互作用亦重要。於ZnO奈米懸浮液中，NaCl、pH與HA交互作用下，HA濃度對於聚集與沉降速率有顯著影響，pH與HA之交互作用對於沉降速率之影響亦重要。當Na2SO4、pH與HA交互作用下於聚集速率方面，HA濃度有顯著影響且pH與HA之間之交互作用亦重要；於沉降速率中各因子間之交互作用均無顯著影響。

中文關鍵字

奈米微粒懸浮液;聚集;沉降

類型	檔名	檔案大小	說明	最新版公開日期
期末報告	2011期末報告-1226.pdf	9MB		2012/3/1 上午 12:00:00

摘要	The two nanoparticles (NPs), TiO2 and ZnO, in aqueous suspensions were identified in nanoscale by a transmission electron microscopy (TEM) and dynamic light scattering (DLS). Pretreatment process including filtration, centrifugation, and settling was evaluated for the analysis of NPs in the aquatic environment. Centrifugation(4060 G, 2 min) can be used to remove large particles on DLS analysis and the recovery was 74%-87%. For dissolved NPs, the solution can be filtered with a centrifugal ultrafilter and then calculated the real NPs concentration by the difference from total NPs concentration. The combination of the centrifugation before the DLS and concentration measurement after digestion are suggested. Finally, the size should be also confirmed by electron microscopies. For various aquatic parameters, the particle concentration from 10 mg/L to 1 g/L and 100 mg/L to 1 g/L did not affect the particle size of TiO2 and ZnO, respectively. We used 100 mg/L as the experiment concentration. The temperature in the range of 15~35℃ did not affect the stability of NPs. When the pH value closes to pHpzc of NPs, around 6.0±0.7 for TiO2 and 10.3±0.6 for ZnO, the obvious aggregation and sedimentation behaviors were found. With an increase of ionic strength, the particle size of NPs increased more quickly. The critical aggragation concentration (CAC) values for TiO2 NPs were 100 meq/L and 1.5 meq/L for Cl- and SO42-, respectively. Also, for ZnO, the CAC values were 10 meq/L and 0.2 meq/L for Cl- and SO42-, respectively. DLVO analysis consists with CAC results. When humic acid (HA) concentrations were 20 mg/L and 1 mg/L for TiO2 and ZnO NPs, NPs aggregated due to the surface of particles covered by SRHA to let surface charge near zero. For pH, NaCl and SRHA interaction, the most significant factors are SRHA concentration and pH for aggreagation and sedimentation, respectively, in TiO2 NPs suspensions. However, there are no significant interactions for two factors. For TiO2 NPs suspensions under different pH, Na2SO4 and SRHA, the most significant factors for aggregation and sedimentation are both SRHA and pH. The interaction between SRHA and pH value is significant. For ZnO NPs, with different pH, NaCl and SRHA, the most significant factor is SRHA. The interaction between SRHA and pH is significant for sedimentation. For ZnO under different pH, Na2SO4 and SRHA, the most significant factor for aggregation is SRHA and also the interaction between SRHA and pH. However, no significant factor can be observed for sedimentation. Overall, these factors generally affect the aggregation and sedimentation significantly.
英文關鍵字	nanoparticle suspension;aggregation;sedimentation

摘要

The two nanoparticles (NPs), TiO2 and ZnO, in aqueous suspensions were identified in nanoscale by a transmission electron microscopy (TEM) and dynamic light scattering (DLS). Pretreatment process including filtration, centrifugation, and settling was evaluated for the analysis of NPs in the aquatic environment. Centrifugation(4060 G, 2 min) can be used to remove large particles on DLS analysis and the recovery was 74%-87%. For dissolved NPs, the solution can be filtered with a centrifugal ultrafilter and then calculated the real NPs concentration by the difference from total NPs concentration. The combination of the centrifugation before the DLS and concentration measurement after digestion are suggested. Finally, the size should be also confirmed by electron microscopies. For various aquatic parameters, the particle concentration from 10 mg/L to 1 g/L and 100 mg/L to 1 g/L did not affect the particle size of TiO2 and ZnO, respectively. We used 100 mg/L as the experiment concentration. The temperature in the range of 15~35℃ did not affect the stability of NPs. When the pH value closes to pHpzc of NPs, around 6.0±0.7 for TiO2 and 10.3±0.6 for ZnO, the obvious aggregation and sedimentation behaviors were found. With an increase of ionic strength, the particle size of NPs increased more quickly. The critical aggragation concentration (CAC) values for TiO2 NPs were 100 meq/L and 1.5 meq/L for Cl- and SO42-, respectively. Also, for ZnO, the CAC values were 10 meq/L and 0.2 meq/L for Cl- and SO42-, respectively. DLVO analysis consists with CAC results. When humic acid (HA) concentrations were 20 mg/L and 1 mg/L for TiO2 and ZnO NPs, NPs aggregated due to the surface of particles covered by SRHA to let surface charge near zero. For pH, NaCl and SRHA interaction, the most significant factors are SRHA concentration and pH for aggreagation and sedimentation, respectively, in TiO2 NPs suspensions. However, there are no significant interactions for two factors. For TiO2 NPs suspensions under different pH, Na2SO4 and SRHA, the most significant factors for aggregation and sedimentation are both SRHA and pH. The interaction between SRHA and pH value is significant. For ZnO NPs, with different pH, NaCl and SRHA, the most significant factor is SRHA. The interaction between SRHA and pH is significant for sedimentation. For ZnO under different pH, Na2SO4 and SRHA, the most significant factor for aggregation is SRHA and also the interaction between SRHA and pH. However, no significant factor can be observed for sedimentation. Overall, these factors generally affect the aggregation and sedimentation significantly.

英文關鍵字

nanoparticle suspension;aggregation;sedimentation