【作者】 张利刚；

【导师】 彭人勇；

【作者基本信息】 青岛科技大学 ， 环境科学， 2011， 硕士

【摘要】 甲醛已被世界卫生组织（WHO）确定为致癌和致畸物质,是公认的变态反应源,也是潜在的强致突变物之一。甲醛为较高毒性的物质,在我国有毒化学品优先控制名单上甲醛高居第二位。本文以TiCl4为主要原料,在低温条件下制备出了TiO₂和P-TiO₂溶胶,并对产品分别进行了XRD、TEM、UV-vis和FT-IR表征及对甲基红溶液的降解测试;以牛皮纸、烟包纸和铜版纸为载体负载制备的TiO₂溶胶和P-TiO₂溶胶用于降解室内低浓度污染气体甲醛,分别通过尝试性实验、正交实验和单因素实验研究了各种反应因素对甲醛气体降解率的影响,并在此基础上对其重复利用率进行了探索。实验结果表明:采用溶胶-凝胶法制备的纳米TiO₂及P-TiO₂均呈锐钛矿晶型且具有良好的分散性;通过对甲基红溶液的降解实验结果可以看出:与纳米TiO₂相比,P-TiO₂无论是微观结构还是光催化性能都更具明显优势;甲醛气体降解的初步研究结果表明,以牛皮纸为载体负载的P-TiO₂光催化剂对甲醛气体的降解效果优于TiO₂光催化剂,在同等条件下降解率相对提高了近20个百分点;尝试性的实验结果表明:甲醛气体的初始浓度、反应时周围环境的湿度状况、反应时溶胶的pH值、添加金属离子的影响等因素在甲醛气体的降解实验中都起到了一定的作用,可以作为正交实验综合考察的因素;单因素实验结果表明:溶胶的最佳pH值为5.50,反应器内最佳湿度条件为接近55%,而甲醛气体的初始浓度最佳范围为3.00mg/m³左右;正交实验的验证性实验结果表明:将pH值为5.50的溶胶负载于牛皮纸上,反应器内湿度为55%左右,甲醛气体初始浓度为3.08mg/m³,加入的Cu2+离子体积为6.00mL,于紫外光照条件下反应120min时,甲醛气体的降解率达到了97.39%,其浓度由3.08mg/m³下降到了0.0803mg/m³;重复利用率实验结果表明:当纸载光催化剂重复利用一次时,甲醛气体的降解率为48.08%,重复利用两次的降解率是21.52%,重复利用三次的降解率为3.69%。更多还原

【Abstract】 the World Health Organization （WHO）, and also a recognized source of allergy and potentially one of the strong mutagen. Formaldehyde was a high toxic substance, which was listed in the second place in our state toxic chemicals priority to control. In this paper, the TiO₂ sol and the P-TiO₂ sol were prepared at low temperatures when TiCl4 was as the main raw material, and the products were characterized by methods of XRD, TEM, UV-vis and FT-IR, respectively. The degradation rate of methyl red solution was also tested; low concentrations of indoor air pollution-formaldehyde gas was degradated by the TiO₂ sol and P-TiO₂ sol loaded on the kraft paper, cigarette paper and coated paper; various reaction factors influencing the degradation rate of formaldehyde gas were studied by tentative experiments, orthogonal experiments and single factor experiments respectively, and its reuse rate was also explored on this basis.The results showed that the crystal structures of nano-P-TiO₂ and nano-TiO₂ prepared by sol-gel method were anatase phase and a good dispersion; the test experiment results of methyl red solution indicated that P-TiO₂ sol compared with nano-TiO₂ sol demonstrated more obvious advantages in microstructure and photocatalytic properties; preliminary degradation results of formaldehyde gas revealed that P-TiO₂ photocatalyst loaded on the kraft paper was prior to TiO₂ photocatalyst in photocatalytic degradation of formaldehyde gas under the same conditions, and the degradation rate increased nearly 20 percentage points relatively; the tentative experimental results proclaimed that the following factors such as the initial concentration of formaldehyde, the humidity of ambient conditions, pH value, reaction time and the impact of metal ions added had played a key role in the degradation experiments of formaldehyde gas, which were also served as comprehensive factors surveyed in orthogonal experiments properly; the single fartor experimental results indicated that the best pH of TiO₂ sol was about 5.50, and the best humidity of the reactor was close to 55%, and the best initial concentration of formaldehyde gas was about 3.00 mg/m³; the verification test results of orthogonal experimental indicated that the degradation rate of formaldehyde gas could reach 97.39%, whose concentration decresed from 3.08 mg/m³ to 0.0803mg/m³ when pH value of the sol loaded on kraft papers was about 5.50, the humidity was about 55% in the reactor, the initial concentration of formaldehyde gas was 3.08mg/m³, the added volume of Cu²⁺ ions was 6.00mL, and reacted for 120min under UV irradiation; the reuse experiment results displayed that the degradation rate of formaldehyde gas was 48.08% when the photocatalyst loaded on papers was used once time, and the degradation rate is 21.52% when was used twice, and the degradation rate of the three times was 3.69%.更多还原