發(fā)布時(shí)間：2018-01-24 22:01

  本文關(guān)鍵詞： 氫氧化鎂 球形氧化鎂 苯酚降解 臭氧氧化　出處：《北京化工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文以氨水及硫酸鎂為原料,研究純度較高、單體分散性較好的球形氧化鎂制備工藝。本文采用靜態(tài)揮發(fā)實(shí)驗(yàn),即在密閉容器中,通過氨水揮發(fā)的氨氣與硫酸鎂溶液經(jīng)氣液接觸反應(yīng),制備出花球形氫氧化鎂顆粒,然后對花球形氫氧化鎂顆粒進(jìn)行NaOH溶液洗滌,得到表面較為光滑且純度較高的球形氫氧化鎂,經(jīng)過對球形氫氧化鎂進(jìn)行煅燒得到球形氧化鎂顆粒。期間考察了各實(shí)驗(yàn)參數(shù),如反應(yīng)溫度、反應(yīng)時(shí)間、初始反應(yīng)物濃度等,對花球形氫氧化鎂產(chǎn)品微觀形貌及結(jié)構(gòu)的影響,研究了制備過程的工藝條件；經(jīng)過對產(chǎn)品進(jìn)行SEM、XRD、TG-DTG等測試及表征,并通過將晶體生長理論與氫氧化鎂晶體結(jié)構(gòu)相結(jié)合,對產(chǎn)物的生長機(jī)理做出了探討。此外,還考察了煅燒溫度對球形氧化鎂粉體的檸檬酸活性值及形貌的影響,并將球形氧化鎂應(yīng)用于臭氧氧化處理苯酚廢水實(shí)驗(yàn),考察反應(yīng)過程中球形氧化鎂的作用。研究結(jié)果表明：以不同鎂鹽作為實(shí)驗(yàn)原料時(shí),只有硫酸鎂利于合成結(jié)構(gòu)完整的球形氫氧化鎂前驅(qū)體顆粒；室溫條件下,當(dāng)硫酸鎂溶液濃度為0.5 mol/L,反應(yīng)時(shí)間為24 h時(shí),與揮發(fā)的氨氣進(jìn)行反應(yīng),能夠得到球形完整、單體分散較好、粒徑大小在7-8 um左右的球形氫氧化鎂前驅(qū)體顆粒：將球形氫氧化鎂前驅(qū)體進(jìn)行4次洗滌,洗滌條件為：將球形氫氧化鎂前驅(qū)體顆粒加入到30℃下濃度為0.2 mol/L的NaOH溶液中攪拌2 h,然后過濾干燥,可以得到純度較高且表面較為光滑的球形氫氧化鎂產(chǎn)品。對球形氫氧化鎂產(chǎn)品在600℃下煅燒2 h,得到表面較為光滑、結(jié)構(gòu)完整的球形氧化鎂。在臭氧氧化降解苯酚實(shí)驗(yàn)中,分別將不同的堿性物加入到苯酚模擬廢水溶液中攪拌1h后,通入臭氧進(jìn)行氧化反應(yīng),反應(yīng)結(jié)束時(shí),添加球形氧化鎂的苯酚溶液中的苯酚降解速率比添加適量NaOH要高13.1%,比輕燒鎂高18.8%,比空白實(shí)驗(yàn)高33.7%,說明添加球形氧化鎂對于臭氧氧化降解苯酚廢水實(shí)驗(yàn)具有更強(qiáng)的促進(jìn)作用。此外,添加球形氧化鎂還有其他優(yōu)點(diǎn),例如不增加廢水鹽度,不會(huì)產(chǎn)生二次污染等。
[Abstract]:In this paper, ammonia water and magnesium sulfate were used as raw materials to study the preparation process of spherical magnesium oxide with high purity and good monomer dispersion. In this paper, static volatilization experiment was carried out, that is, in a closed vessel. The spherical magnesium hydroxide particles were prepared by the gas-liquid contact reaction between ammonia and magnesium sulfate solution, and then washed with NaOH solution. Spherical magnesium hydroxide with smooth surface and high purity was obtained. After calcination of spherical magnesium hydroxide, spherical magnesium hydroxide particles were obtained. The experimental parameters, such as reaction temperature and reaction time, were investigated. The effect of initial reactant concentration on the microstructure and morphology of spherical magnesium hydroxide was studied. The growth mechanism of the product was discussed by combining the crystal growth theory with the crystal structure of magnesium hydroxide. The effect of calcination temperature on citric acid activity and morphology of spherical magnesium oxide powder was also investigated, and spherical magnesium oxide was used in ozone oxidation treatment of phenol wastewater. The effect of spherical magnesium oxide in the reaction process was investigated. The results showed that when different magnesium salts were used as raw materials, only magnesium sulfate was beneficial to the synthesis of spherical magnesium hydroxide precursor particles with intact structure. At room temperature, when the concentration of magnesium sulfate solution is 0.5 mol / L and the reaction time is 24 h, the reaction with volatile ammonia can obtain spherical integrity and better dispersion of monomer. Spherical magnesium hydroxide precursor particles with particle size of 7-8 um: the spherical magnesium hydroxide precursor was washed for 4 times. The washing conditions were as follows: the spherical magnesium hydroxide precursor was added to the NaOH solution at 30 鈩，

本文編號(hào)：1461137