2006-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/712099摘要：零價鐵自發性釋放電子還原破壞水中污染物質已引起廣泛研究與運用，過去十五年，多種含氯烷類、烯類與農藥、放射性物質、重金屬以及氧酸根離子的實驗室與模場研究建立了基礎的反應機制與動力學的數據。目前研究重點除了有效提高污染物降解速率外，另一關注的焦點在於降低毒性副產物的生成與累積，鐵表面鍍少量貴重金屬形成催化效應是最顯著的強化方法，雖然本研究團隊已發現Cu/Fe雙金屬降解中性硝酸鹽溶液的速率遠高於Fe、Pd/Fe與Pt/Fe等，由於亞硝酸鹽吸附於銅表面的親和力遠低於硝酸鹽，導致出流水殘餘約30-40%氮質量平衡的亞硝酸鹽量，因此，改良復載金屬的表面特性以減少亞硝酸鹽的生成，將可提升此一還原性材料的實用價值。 本計畫欲以自行開發的技術覆載第二催化性金屬(如Pd, Pt, Au)於Cu/Fe表面，利用第二催化性金屬對反應中間產物-亞硝酸鹽的高親和力接續提供還原能力，白金族貴金屬為催化劑已被證實可有效還原亞硝酸為氨氮或氮氣，但對硝酸鹽卻無明顯降解能力，相反地，銅金屬可轉化硝酸鹽為亞硝酸鹽，卻無法持續還原亞硝酸鹽，因此，結合銅與白金族為雙金屬催化劑，同時催化鐵腐蝕反應( )產生吸附態氫原子於催化劑表<br> Abstract: Extensive researches in the past fifteen years have demonstrated that chemical reduction of many substances in the environment such as halogenated organic compounds, heavy metals, and oxo-anions can be coupled to Fe0 oxidation. The impact of any products formed via target pollutant transformation is of vital important for both in-situ and above ground treatment system. Thus, in addition to increasing the degradation rate of target pollutant, a proper catalyst is implemented to solve the problem of production and accumulation of toxic byproducts. The Deposition of small amounts of Cu onto iron has been shown to be more activity toward nitrate than Pd, Pt, and Au. However, the mass of residual nitrite was observed at about 15-40% of the degraded nitrate in the Cu/Fe system due to its less affinity to copper. Thus, a modified method to Cu/Fe surface is promising and effective to enhance the rate of nitrate removal and to prevent from the accumulation of nitrite. In this study, the second catalytic metal such as Pd, Pt, and Au were deposited onto the first catalytic metal surface, Cu, via the patent method. The combination of high affinity of Cu toward nitrate and Pd toward nitrite, adsorbed atomic hydrogen attacks the target pollutant, nitrate, on copper surface; and nitrite was degraded on Pd surface into nitrogen or ammonia, entering into the solution. There are three phases in this work: firstly, the preparation and characteristics of various reductive materials were conducted via BET, SEM/EDX, and XPS and then the experiments of the degradation of nitrate via these reductive materials to evaluate their catalytic activity and selectivity. Finally, the effects of solution containing HS-, SO4-, and CO3- on the catalyst deactivation were examined.零價鐵硝酸鹽亞硝酸鹽雙金屬催化劑催化氫解nitratezero-valent metalnitritebimetallic catalystcatalytic hydrogenation