本文選題：Cu-SSZ-13　切入點(diǎn)：鈦交換　出處：《太原理工大學(xué)》2017年碩士論文

【摘要】：汽車尾氣是城市大氣污染的主要來源之一,其中氮氧化物(NOx)是形成光化學(xué)煙霧和酸雨重要因素。NH_3-SCR技術(shù)被認(rèn)為是目前最有前景的機(jī)動車尾氣脫硝技術(shù)之一,其核心是高效穩(wěn)定催化劑的研發(fā)。分子篩是目前國內(nèi)外學(xué)者研究的重點(diǎn),其中Cu-SSZ-13催化劑由于其優(yōu)異的脫硝活性、N_2選擇性和水熱穩(wěn)定性而受到廣泛關(guān)注。在Cu-SSZ-13分子篩中引入雜原子,可以豐富分子篩的骨架結(jié)構(gòu),調(diào)節(jié)活性金屬銅的分布和狀態(tài),進(jìn)而提高其脫硝反應(yīng)活性、選擇性和水熱穩(wěn)定性。Ti是一種常被用來改性分子篩的元素。本課題通過離子交換的方式在原位制備的Cu-SSZ-13分子篩催化劑和傳統(tǒng)水熱合成法制備的SSZ-13分子篩催化劑中引入鈦原子,考察TiCl_4濃度、離子交換時(shí)間、溫度以及Ti和Cu交換順序?qū)u-SSZ-13分子篩催化劑脫硝活性、選擇性、水熱穩(wěn)定性及其物理化學(xué)性質(zhì)的影響。實(shí)驗(yàn)得到主要結(jié)論如下:(1)利用離子交換法對原位水熱合成法制備的Cu-SSZ-13催化劑進(jìn)行改性,通過NH_3-SCR脫硝實(shí)驗(yàn)評價(jià),優(yōu)化出TiCl_4的最佳濃度為0.075 mol/L,最佳交換溫度為35 ℃,最佳交換時(shí)間為6 h。在此條件下,樣品具有相對較好的脫硝活性和水熱穩(wěn)定性。老化后樣品的比表面積增大,低溫活性與新鮮樣品相差不大。(2)在傳統(tǒng)水熱合成法制備SSZ-13分在篩的基礎(chǔ)上,考察Cu和Ti交換順序?qū)γ撓跣阅艿挠绊�。鈦交換是用0.075 mol/L的TiCl_4溶液,在35 ℃水浴條件下與樣品交換6 h。銅交換是用0.025 mol/L的硫酸銅溶液在80 ℃條件下水浴交換1 h。結(jié)果表明:鈦原子的引入提高了SSZ-13催化劑的高溫活性;先交換鈦再交換銅的樣品具有相對較好的水熱穩(wěn)定性。
[Abstract]:Automobile exhaust is one of the main sources of urban air pollution, among which no _ x (no _ x) is an important factor in photochemical smog and acid rain. NH _ S _ 3-SCR technology is considered to be one of the most promising denitrification technologies. Its core is the research and development of high efficient and stable catalyst. Molecular sieve is the focus of domestic and foreign scholars. Among them, Cu-SSZ-13 catalyst has attracted wide attention due to its excellent denitrification activity, N _ 2 selectivity and hydrothermal stability. Introducing hetero-atoms into Cu-SSZ-13 molecular sieve can enrich the skeleton structure of molecular sieve and regulate the distribution and state of active copper. Then the denitrification reaction activity was improved. Selectivity and hydrothermal stability. Ti is an element commonly used to modify molecular sieves. Titanium atoms are introduced into Cu-SSZ-13 molecular sieve catalysts prepared in situ and SSZ-13 molecular sieve catalysts prepared by traditional hydrothermal synthesis by ion exchange. The activity and selectivity of TiCl_4 concentration, ion exchange time, temperature and Ti and Cu exchange sequence for denitrification of Cu-SSZ-13 molecular sieve catalyst were investigated. The main conclusions are as follows: (1) the Cu-SSZ-13 catalyst prepared by in situ hydrothermal synthesis was modified by ion exchange method and evaluated by NH_3-SCR denitrification experiment. The optimum concentration of TiCl_4 is 0.075 mol / L, the best exchange temperature is 35 鈩，

本文編號：1667456