反膠團萃取牛血清白蛋白論文-資料下載頁
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【正文】 emulsions [ 15,16],the reacting species in microemulsions I and II einto contact. This led to the precipitation of cobaltironhydroxide particles within the nanosize aqueousdroplets of the microemulsion. Since the positionsof the two microemulsions (I and II) are identical,differing only in the nature of the aqueous phase,the microemulsion does not get destabilized uponmixing. The aqueous droplets act as constrainednanosize reactors for the precipitation reaction, as thesurfactant monolayer provides a barrier restrictingthe growth of the hydroxide particles. This surfactantmonolayer also hinders the coagulation of particles.The cobaltiron hydroxide precipitate synthesizedin microemulsions was separated in a Sorvall RC5BSuperspeed centrifuge at 7000 rpm for 10 min. Theprecipitate was then washed with a 1:1 mixture ofmethanol and chloroform, followed by pure methanolto remove any oil and surfactant from the particles.The precipitate was then dried at 100176。C. Sintering ofparticles is not expected at this temperature. Theprecursors were then calcined at 600176。C for 5 h forplete conversion of the hydroxide into the magneticferrite (CoFezOa).Phase analysis of the calcined powder was doneby powder Xray diffraction on a Philips PW1700powder diffractometer at room temperature using CuKo~ radiation at 40 kV and 20 mA.Transmission electron microscopy (TEM) wasused to study the size and shape of the calcinedparticles. The calcined powder was ultrasonicallydispersed in methanol prior to depositing it onto acarbon coated TEM grid. A JEOL 200CX transmissionelectron microscope was used for these studies.Magnetization (MH loop) measurements weredone on an unoriented, random assembly of particlesat room temperature on a vibrating sample magnetometer(LDJ 9600) with a maximum applied field of5 kOe. The sample was prepared by hand pressingthe calcined powder into a cylindrical pellet. Nofurther heat treatments were done on the pellet.高效鈷鐵酸鹽微粒通過水相有機相系統(tǒng)的合成 原料硝酸鐵和硝酸鈷( 分析純 % )從Aldrich被購買； 氫氧化銨( 含NH3 38% )； CTAB (技術(shù)的等級)和丁醇，甲醇，和三氯甲烷(所有HPLC等級)從科學(xué)購銷處購買。辛烷( 分析純含量97% )從菲利普購買，所有試劑沒有較進(jìn)一步的凈化而被使用。水是蒸餾水。. 方法含有CTAB的一個微乳狀體系作為表面活性劑，丁醇作為助表面活性劑，辛烷用做有機溶劑。這種體系是溶解 (溶解含水的聚集體 )大量的含水的納米聚集體 [ 24 ]。微乳狀體系通過在CTAB/丁醇/辛烷系統(tǒng)中加入不同濃度的鹽而形成的。帶有相同組分的兩微乳狀體系 (I和II )處于不同的含水的階段。( II ) M硝酸鐵的一種固溶體。微乳狀體系II的含水階段能溶解氫氧化銨，沉淀劑濃度大于被要求的化學(xué)計量的10%。然后這兩微乳狀體系被充分混合。因為反膠團體系 [ 15,16 ]的含水的核心的頻繁的沖撞，微乳狀體系 I和II中的物種開始反應(yīng)。在這期間導(dǎo)致cobaltiron氫氧化物微粒的納米集微乳狀體系的含水量的改變。由于兩微乳狀體系 (I和II )的組分相同，在含水的階段的性質(zhì)中卻是不同的，微乳狀體系直到混合時才被充分搖動。當(dāng)表面活性劑單層提供限制氫氧化物微粒的增長的一個障礙時，含水的聚集體為了反應(yīng)充當(dāng)約束納米集反應(yīng)堆。表面活性劑單層也防止凝結(jié)微粒在微乳狀體系中鈷鐵氫氧化物在7000轉(zhuǎn)/分鐘的一個 RC5B 高速離心機中被離心10分鐘，然后被洗滌以便從微粒中除去任何油和表面活化劑甲醇和三氯甲烷的1:1種混合物，最后是純粹的甲醇。然后析出物在100176。C被弄干，微粒的干燥不能在這溫度下。然后先在600176。C煅燒5小時為了把氫氧化物完全轉(zhuǎn)化成為磁性的鐵酸鹽( CoFezOa )對煅燒的粉的階段分析在室溫下用菲利普PW1700粉衍射計 ，在40 kV和20 mA使用Cu K~輻射完成。傳輸電子顯微鏡方法( TEM )被用來學(xué)習(xí)煅燒的微粒的大小和形狀。煅燒的粉末先把它存放到一塊碳涂上一層的TEM柵格上在甲醇中疏散，用JEOL 200CX轉(zhuǎn)播電子顯微鏡進(jìn)行研究。磁化( M H回路)測量方法是在室溫下的一個最大限度應(yīng)用的領(lǐng)域的振動的抽樣磁強計( LDJ 9600 )上在帶有5 kOe上被完成不定向的微粒的隨機集結(jié)。通過把樣品進(jìn)入一個圓柱形的小球，進(jìn)行煅燒， 沒有較進(jìn)一步的熱處理在小球上被完成
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