稀土元素?fù)诫s納米ZnO功能材料的制備及性能研究
發(fā)布時(shí)間:2018-06-21 14:20
本文選題:納米氧化鋅 + 摻雜 ; 參考:《沈陽(yáng)工業(yè)大學(xué)》2017年碩士論文
【摘要】:光催化氧化技術(shù)具有清潔性、高效性以及穩(wěn)定性等眾多特點(diǎn),能夠?qū)⒐饽苻D(zhuǎn)化為化學(xué)能,產(chǎn)生羥基自由基氧化水體中的難降解污染物質(zhì),受到了廣泛的關(guān)注,為處理高難降解廢水提供了一種新的方法。光催化技術(shù)中最重要的就是光催化材料的制備研究,半導(dǎo)體材料氧化鋅是目前研究最熱的光催化材料,具有很好的應(yīng)用前景。本文研究納米氧化鋅的制備方法,通過(guò)稀土元素La摻雜和La-Cd共摻雜的研究,制備出高效穩(wěn)定的光催化劑?疾鞆(fù)合催化劑的制備影響因素,以活性黑KNB染料溶液為模擬廢水進(jìn)行光催化降解,找出最佳的光催化降解條件并測(cè)試復(fù)合催化劑的穩(wěn)定性。本文的主要研究成果如下:(1)微波法為納米氧化鋅的最佳制備工藝,并通過(guò)XRD和SEM表征對(duì)其微觀結(jié)構(gòu)進(jìn)行分析,確定晶型為六方纖鋅礦結(jié)構(gòu)。紫外光照射下,利用不同條件制備的氧化鋅對(duì)濃度為0.04g/L的活性黑KNB染料廢水進(jìn)行光催化降解,結(jié)果表明微波法制備氧化鋅材料的最佳工藝條件為:n(六水合硝酸鋅):n(尿素)=1:3,微波反應(yīng)時(shí)間30min,微波加熱功率640W,煅燒溫度500℃。(2)La和Cd元素的摻雜未改變納米氧化鋅的主體結(jié)構(gòu),摻雜后的復(fù)合催化劑具有較高的光催化活性,La-Cd/ZnO復(fù)合光催化劑的最佳制備工藝為:鑭鎘摻雜比為2:1,微波反應(yīng)時(shí)間30min,加熱功率640W,煅燒溫度500℃,反應(yīng)溶液pH為7,最佳制備條件下,光催化降解活性黑KNB染料的降解率為98.9%。通過(guò)正交試驗(yàn)極差分析可知,制備因素對(duì)La-Cd/ZnO復(fù)合催化劑活性的影響排序?yàn)?煅燒溫度鑭鎘摻雜比微波功率反應(yīng)溶液pH。(3)考察光催化反應(yīng)條件對(duì)La-Cd/ZnO復(fù)合催化劑降解染料廢水的影響,實(shí)驗(yàn)結(jié)果證明光催化的最佳反應(yīng)條件為:廢水pH為7,染料初始濃度為0.08g/L,投加量為0.1g。紫外光照射2h對(duì)活性黑KNB的去除率為92.2%,通過(guò)多次重復(fù)使用,La-Cd/ZnO復(fù)合催化劑仍具有較高的光催化活性。
[Abstract]:Photocatalytic oxidation technology has many characteristics, such as cleanness, high efficiency and stability, which can convert light energy into chemical energy and produce hydroxyl radical oxidation of refractory pollutants in water. It provides a new method for the treatment of high-difficult-degradable wastewater. The preparation of photocatalytic materials is the most important in photocatalytic technology. The semiconductor material zinc oxide is the hottest photocatalytic material and has a good application prospect. In this paper, the preparation method of nanometer zinc oxide was studied, and high efficient and stable photocatalyst was prepared by La doping and La-Cd co-doping. The factors affecting the preparation of the composite catalyst were investigated. The reactive black KNB dye solution was used as the simulated wastewater for photocatalytic degradation. The optimum photocatalytic degradation conditions were found and the stability of the composite catalyst was tested. The main results of this paper are as follows: (1) Microwave method is the best preparation technology of nano-ZnO. The microstructure of nano-ZnO is analyzed by XRD and SEM, and the crystal structure is determined to be hexagonal wurtzite structure. Under ultraviolet irradiation, the reactive black KNB dye wastewater with 0.04g / L concentration of zinc oxide prepared under different conditions was photocatalytic degraded. The results show that the optimum technological conditions for the preparation of zinc oxide materials by microwave are: 1: n (zinc nitrate hexahydrate: 1: 3), microwave reaction time 30 min, microwave heating power 640 W, calcination temperature 500 鈩,
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