【作者】 侯春燕；

【导师】 丁永生；

【作者基本信息】 大连海事大学 ， 环境科学， 2006， 硕士

【摘要】 工业的发展使得地球上有限的水资源受到的污染日益严重。水质的恶化严重威胁着人们的健康。去除水中的有毒、有害化学物质已成为环保领域的一项重要工作。半导体光催化治理有机废水技术,具有技术能耗低、操作简便、适用范围广、不易造成二次污染等特点,因此,在水处理方面日益受到人们的重视。一些半导体材料已被研究且应用到光催化水处理中,而且其制备和化学修饰也引起了人们的广泛关注。 本论文利用液相沉淀—热分解法制备纳米ZnO光催化剂,采用FT—IR、XRD和SEM对所制得的一系列光催化剂进行了结构表征,研究了该类材料的光致激发性能,并对该光催化剂降解甲基橙水溶液的催化性能进行了评价,从而确定了制备ZnO光催化剂的温度、时间条件,分别为750℃和2h。 通过对催化剂投加量、溶液初始pH值、待处理甲基橙的初始浓度、通氧等影响因素的研究,发现溶液初始pH值对降解效率的影响甚微,当pH值在3.69～11.07范围内变化时,仅在94.82%～95.88%范围内变化。通氧条件下,使用自组装ZnO（2h—750℃）可将光降解甲基橙的效率由66.48%提高到95.88%。在浓度为10mg/L以下时,其初始吸光度值（A₀）与去除率（η）关系曲线可表示为η=-10.08325A+97.00205。 通过本文介绍的制备方法可以得到一种高效、低成本的纳米ZnO光催化剂,该催化剂具有特殊的结构和光致发光性能。在降解甲基橙水溶液过程中使用该催化剂,可以大大提高光催化效率。更多还原

【Abstract】 With the development of the industry, the limited water resources are being polluted and causing the serious problems. The worsening of the water quality undoubtedly damage the health of mankind as well as the entire ecosystem. To wipe off the toxic and lethal chemical materials from the water becomes a crucial task for environmental protection. The development of photocatalytic techniques to degradate organic pollutants in waste water has attracted increasingly attentions due to their energy-effectiveness, flexible application and non re-pollution etc. Some semiconductors have been regarded as potential candidate photocatalysts to treat waste water. Therefore, more attentions have been paid to their preparation and modification of useful semiconductiors using chemistry techniques.In this paper, ZnO photocatalyst preparation via the chemical deposition and decompostion method was introduecd. The structure and properties of ZnO powders was investigated by fourier transform infrared spectra（FT-IR）, Scanning electron microscopy（SEM） and X-ray diffraction（XRD）, respectively. The room temperature photoluminescence of the ZnO powders was examined and its activity of photocatalytic descomposition of methyl orange was described, too. It was found that We can obtain an approving ZnO photocatalyst if the sample was calcined at 950℃ for 2h.The decolorization efficiency of methyl orange was studied, while the effects of the pH, O₂, the initial concentration of analyts as well as the dosage of catalyst were considered correspondingly. In wide range of the initial pH, from 3.69 to 11.07, the ratio of the decoloration is good but changed a little （from 94.82% to 95.88%）. The decolorization efficiency by using assembly-ZnO can be enhanced from 66.48 % to 95.88%. When the initial concentration was less than 10mg/L, the relation of the initial absorbency（A₀） and the decolorization efficiency of methyl orange（η） is linear and can be discribed by equation η =-10.08325 A₀+97.00205.We can obtain a high activity and low cost ZnO photocatalyst by the preparation method which is introduced in this paper. This photocatalyst has a unique structureand pohotoluminescence character. The decolorization efficiency can be enhanced greatly by using assembly-ZnO.更多还原