發(fā)布時間：2018-01-19 12:42

  本文關(guān)鍵詞： 電氧化 燃料電池 陽極催化劑 脫氮 鈷鎳銅　出處：《浙江大學》2017年博士論文　論文類型：學位論文

【摘要】：環(huán)境中的氨及其衍生物如尿素、氨基酸等是一類常見的含氮污染物。生物法處理含氮廢水是一傳統(tǒng)的方法、有一定的經(jīng)濟性,但周期長、受C/N比和濃度限制等缺點,且消耗大量能量。電化學方法直接提供電能達到氧化分解目的,可以有效地、快速處理,但是高昂的成本限制了電化學方法的大規(guī)模運用。事實上,含氮廢水中含有化學能,在合適的催化劑作用下,尿素、氨基酸和氨可以發(fā)生氧化反應,產(chǎn)生氮氣并釋放電子。通過電化學體系氨和其衍生物轉(zhuǎn)化為電能或氫能,這樣在處理了污染物的同時回收了能源,即污染物的能源化處理。本論文組裝了以含氮化合物為燃料的電對燃料電池,將儲存在其中的電能直接予以提取。高效穩(wěn)定的陽極催化劑是電化學體系的關(guān)鍵之一,研究制備了非貴金屬Ni/C、NiCo/C、NiCu雙金屬和NiCu氫氧化物納米線催化劑取代傳統(tǒng)的易中毒的貴金屬鉑基陽極催化劑。利用電子顯微鏡、X射線衍射、X射線光電子能譜、電化學測試等手段對催化劑進行表征,構(gòu)建了陰離子交換膜燃料電池體系,成功地以尿素(尿液)、氨基酸作為電子供體在陽極自發(fā)地發(fā)生氧化反應,并以氧氣、六價鉻作為電子受體在陰極進行還原反應,從而將蘊含的化學能直接轉(zhuǎn)化為電能的同時降解污染物。尿素電池在Ni/C和NiCo/C陽極催化劑作用下分別獲得了 1.4 mW cm-2和2.0 mW cm-2的最大功率密度。氨基酸電池在陽極催化劑Ni/C和NiCo/C作用下分別獲得了 1.9 mW cm-2和3.0 mW cm-2的最大功率密度。在尿液-六價鉻兩種污染物組成的燃料電池中,得到了 3.4 W m-2的最大功率密度和1.3 V的開路電壓,尿液中的TOC和TN去除率分別為79.2%和78.4%,同時陰極液中Cr(Ⅵ)的去除率達到了 93%。電化學表征證明NiCu雙金屬催化劑和NiCu氫氧化物納米線催化劑相比于Ni和貴金屬Pt基催化劑具有更好的催化活性和穩(wěn)定性,有助于解決氨電氧化技術(shù)中陽極催化劑的問題。實驗證明,非貴金屬的納米Ni基催化劑可以很好地作為尿素、氨基酸和氨電化學氧化反應的陽極催化劑,處理廢水同時回收能源,這一方法有望成為污染物處理的一種新技術(shù)。此外,尿素、氨基酸和氨是儲氫能源物質(zhì),可以利用富余的電能進行人工合成,再在需要時通過這一電化學體系產(chǎn)電,將是一個新型的化學儲能途徑。
[Abstract]:Ammonia and its derivatives, such as urea and amino acid, are common nitrogen pollutants in the environment. Biological treatment of nitrogen-containing wastewater is a traditional method, which has a certain economy, but the cycle is long. Due to the limitation of C / N ratio and concentration, and consuming a lot of energy, electrochemical method can provide electric energy directly to achieve the purpose of oxidation decomposition, which can be processed efficiently and quickly. However, high costs limit the large-scale use of electrochemical methods. In fact, nitrogen-containing wastewater contains chemical energy, urea, amino acid and ammonia can be oxidized under the appropriate catalyst. Nitrogen is produced and electrons are released. Ammonia and its derivatives are converted into electrical or hydrogen energy through an electrochemical system, which processes pollutants and recovers energy. In this paper, the electric-pair fuel cell with nitrogen compound as fuel was assembled. The high efficient and stable anode catalyst is one of the key factors in electrochemical system. The non-precious metal Ni / C / Ni / Co / C was prepared. NiCu bimetallic and NiCu hydroxide nanowire catalysts were used to replace the traditional toxic platinum based anode catalysts. X-ray photoelectron spectroscopy (XPS) was used to analyze the results of X-ray diffraction. The catalyst was characterized by electrochemical measurement and anion exchange membrane fuel cell system was constructed. The anion exchange membrane fuel cell system was successfully oxidized at anode with urea (uridine, amino acid) as electron donor. Oxygen and hexavalent chromium were used as electron acceptors for the reduction reaction at the cathode. Therefore, the chemical energy contained therein was directly converted into electric energy and the pollutants were degraded simultaneously. 1.4 MW was obtained from urea cell under the action of Ni/C and NiCo/C anode catalyst, respectively. The maximum power density of cm-2 and 2.0 MW cm-2. The Amino Acid Battery obtained 1.9 MW under the action of anodic catalyst Ni/C and NiCo/C, respectively. Maximum power density of cm-2 and 3.0 MW cm-2. In a fuel cell consisting of two contaminants: urine-hexavalent chromium. The maximum power density of 3.4 W m-2 and the open circuit voltage of 1.3V were obtained. The removal rates of TOC and TN in urine were 79.2% and 78.4%, respectively. At the same time, Cr (鈪，

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