直接喷涂改性硅溶胶固载二氧化钛的研究

发布时间：2019-05-07 09:12

【摘要】：二氧化钛是目前使用较多的光催化剂,催化剂一般是粉末状,存在着易流失、难重复利用的特点,因而,二氧化钛的高效、稳定的固载是二氧化钛工业化运用的重要前提。本课题以硅溶胶为粘结剂,采用喷涂法将催化剂和粘结剂的混合液喷涂在铝合金网上,通过对硅溶胶优化和改性,筛选出催化剂的最优制备方法,并考察了固载的催化剂对甲苯的降解活性。进行了直接喷涂硅溶胶固载TiO_2的研究。比较了不同粘结剂固载二氧化钛催化剂的催化活性,结果表明硅溶胶作为粘结剂时,催化剂表现出了最好的效果。为进一步优化催化剂的制备方法,对硅溶胶与二氧化钛的质量比和分散剂进行优化,结果发现,在二氧化钛的质量与二氧化硅的质量比为4:3,六偏磷酸钠的质量分数为2%时,催化剂表现出最好的光催化效果,3 h对甲苯的降解率为98%,矿化率为87%。进行了硅溶胶固载TiO_2表面改性的研究,分别选用氟碳乳液、硅丙乳液、铝溶胶、硅烷偶联剂KH-570进行表面改性,减少催化剂裂痕。发现4种方法都能对催化剂进行改性。其中硅烷偶联剂改性后的催化剂,光催化效果最佳,当二氧化钛与KH-570质量比比为10:3时,p H为2时,催化剂表现出最好的光催化效果,3 h内对甲苯的降解率为94%,矿化率为87%。考察模拟条件下固载TiO_2催化剂降解甲苯的性能研究。在流动态条件下对甲苯进行降解,结果表明,紫外光氧化不能对甲苯进行矿化。考察反应条件对催化剂降解甲苯的影响。结果表明:污染物在反应器中的停留时间对甲苯的影响最大,随着停留时间增加,催化剂对甲苯的降解效果越好;随着甲苯初始度的增加,催化剂对甲苯的降解率减少;随着湿度的增加,催化剂对甲苯的降解率先增大后减小;随着催化剂量的增加,催化剂的降解率增加。当甲苯初始浓度为10 ppm,停留时间为60 s,相对湿度为45%时,催化剂对甲苯的降解率为91.5%,矿化率为71%。考察催化剂对不同有机物的影响,催化剂对醇类、醛类、醚类都有90%矿化。催化剂表现出良好的寿命,在连续使用3星期,催化剂依旧能保持对甲苯88%的降解率。
[Abstract]:Titanium dioxide is the most widely used photocatalyst at present. The catalyst is usually in the form of powder, which is easy to be lost and difficult to be reused. Therefore, the efficient and stable loading of titanium dioxide is an important prerequisite for the industrial application of titanium dioxide. In this paper, silica sol was used as binder, the mixture of catalyst and binder was sprayed on aluminum alloy net by spraying method, and the optimum preparation method of catalyst was selected by optimizing and modifying silica sol. The catalytic activity for toluene degradation was also investigated. The direct spraying of TiO_2 on silica sol was studied. The catalytic activity of titanium dioxide supported on different binders was compared. The results showed that the catalyst showed the best effect when silica sol was used as binder. In order to further optimize the preparation method of catalyst, the mass ratio of silica sol to titanium dioxide and dispersant were optimized. The results showed that the mass ratio of titanium dioxide to silica was 4? When the mass fraction of sodium hexametaphosphate was 2%, the catalyst showed the best photocatalytic effect. The degradation rate of toluene was 98% and the mineralization rate was 87% for 3 h. The surface modification of silica sol-supported TiO_2 was studied. Fluorocarbon emulsion, silicone-acrylic emulsion, aluminum sol and silane coupling agent KH-570 were used to modify the surface of silica sol to reduce the cracking of catalyst. It was found that all four methods could modify the catalyst. When the mass ratio of TIO _ 2 to KH-570 was 10: 3, the catalyst showed the best photocatalytic effect, and the degradation rate of toluene was 94% within 3 h, when the mass ratio of TIO _ 2 to KH-570 was 10: 3, the catalyst showed the best photocatalytic effect. The mineralization rate is 87%. The performance of supported TiO_2 catalyst for toluene degradation under simulated conditions was investigated. Toluene was degraded under dynamic flow conditions, and the results showed that toluene could not be mineralized by UV oxidation. The effect of reaction conditions on the degradation of toluene by catalyst was investigated. The results showed that the residence time of pollutants in the reactor had the greatest influence on toluene, and the degradation efficiency of toluene was better with the increase of residence time, and the degradation rate of toluene decreased with the increase of initial degree of toluene, and the degradation rate of toluene decreased with the increase of initial degree of toluene. With the increase of humidity, the degradation rate of toluene increased first and then decreased, and the degradation rate of catalyst increased with the increase of catalyst dosage. When the initial concentration of toluene was 10 ppm, and the residence time was 60 s and the relative humidity was 45%, the degradation rate of toluene and mineralization rate were 91.5% and 71%, respectively. The effects of catalysts on different organic compounds were investigated. The catalysts had 90% mineralization of alcohols aldehydes and ethers. The catalyst showed a good life. After 3 weeks of continuous use, the catalyst could still keep the degradation rate of p-toluene at 88%.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O614.411;O643.36

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