利用無電鍍法沉積鐵-鎳奈米粒子在氧化鋁粉上之研究

利用無電鍍法沉積鐵-鎳粒子在氧化鋁粉上形成Fe-Ni/Al2O3複合材料，兼具奈米粒子和微米基材特性，以改善目前奈米粒子實際操作的問題包括表面活性強、易團聚、不易保存、不確定建康與環境風險等，以處理日趨複雜的水污染，控制鐵鎳合金無電鍍析鍍的初始時間分析並模擬出可能的鐵鎳共沉積機制，用以解釋在無電鍍鐵鎳中所遭遇的問題，以影像分析技術量測不同溫度、鐵離子濃度下不同時間其鐵鎳合金的析鍍厚度，分析溫度及鐵離子濃度對鍍膜成長速率的影響並計算出各種鐵離子濃度下反應所需活化能。本研究探討製備參數包括：鍍液pH、氧隔絕物、鐵塩純度、鍍液析鍍溫度和鍍液中Fe2+/Ni2+等各參數對Fe-Ni/Al2O3粉鐵含量之影響利用感應式偶合電漿原子放射光譜儀(ICP-OES)定量分析沉積在Al2O3上之單位含鐵量和單位含鎳量，尋找製備高鐵含量之Fe-Ni/Al2O3的最佳參數，結果顯示製備高鐵含量之Fe-Ni/Al2O3粉之最佳參數分別為鍍液pH11、溫度50℃、二甲苯覆蓋鍍液表面和高純度鐵塩。在鍍液中Fe2+/Ni2+比為0.3、1和3下可製得鐵含量為71.47mg/g(18.31at%)、104.03mg/g(25.93at%)和136.25mg/g(32.95at%)之Fe-Ni/Al2O3粉，其中以Fe2+/Ni2+比為3(鍍浴鐵離子占金屬離子75%)最適合用以處理環境水污染物。以L18田口法去除模擬混合污染物廢水以求得最佳處理條件，從結果可得知在Fe-Ni/Al¬2O3添加量5 g/l、pH 9、去除時間360 min污染物濃度分別為AO7 10mg/l、Se- 5mg/g、Pb2+ 10 mg/g其去除率分別為AO7 57.65%，Se- 10.27 %，Pb2+98.70%，其中AO7與Pb2+汙染物濃度皆低於放流水標準，而Se-去除效果較不明顯，最佳去除率為30.66%。製備實驗結果發現鍍浴中鐵鎳離子比例與所沉積的鐵鎳合金中的鐵含量是有很大的差異鍍浴Fe2+/Ni2+比為3實際上鐵離子在所有鍍浴金屬離子中佔有75%之多，但實際析鍍鐵鎳合金鐵僅占32.95 at%不足鍍浴中濃度的一半，為理解此一差異利用TEM及EDS分析並探討鐵鎳共沉積的初始成長狀況、成長速率及活化能，由結果得知鐵鎳共沉積初時是以鐵的沉積速率高於鎳，而鐵本身並非觸媒金屬，因此鐵在初時生長時很有可能遮蔽觸媒金屬表面，此時必須由鎳離子置換金屬鐵使表面重新獲得觸媒金屬而繼續反應，因此鐵鎳合金中鐵所占含量會少於鍍浴中鐵離子含量，而鐵鎳合金的成長速率試驗中也可得知當鍍浴鐵離子含量的提升相對鎳離子含量降低時成長速率也會因此而下降。

關鍵字

鐵鎳奈米粒子；氧化鋁；無電鍍；成長動力學；活化能

並列摘要

ABSTRACT In this study, electroless plating technique was used to fabricate nano particles onto the surface of submicron Al2O3 powders. Then, the composite Fe-Ni nano particles/ Al2O3 was produced by electroless Fe-Ni plating, the treatment ability of mixed pollutants in water, parameters and initial growth kinetic of electroless Fe-Ni plating were studied. Experimental results show that the high iron content on aluminum oxides could be achieve by covering solution with xylene at 50 ℃ and pH 11, using Fe2+/N2+ ratio of 0.3, 1, and 3 , the iron contents of nano-particles could achieve 18.31, 25.93, and 32.95 at%. The initial growth behavior and kinetics were observed by TEM/EDS. The plating rate of Iron is faster than Nickel for initial 5 seconds and Fe-Ni deposit was composed of over 90% Fe with main α-Fe phase. And then, the Fe content decreased sharply and become steady state which Fe/Ni ratio of deposit was uniform and less than original Fe2+/N2+ ratio of plating solution. FeNi3 phase showed at steady state.Finally, the optimum conditions of adding amount of Fe-Ni nano particles/ Al2O3, solution pH, reaction time and pollutants concentration on treating pollutants of dye AO7, Pb2+and HSeO3- were investigated by the Taguchi method.