【作者】 李冬；

【导师】 张承中；

【作者基本信息】 西安建筑科技大学 ， 环境科学， 2007， 硕士

【摘要】 本文研究了采用溶胶-凝胶法制备钛溶胶，运用浸渍-提拉法将其负载在玻璃纤维布上并进行煅烧得到的TiO₂光催化剂，在自制气-固光催化反应装置上进行H₂S无机恶臭气体的降解性能研究。在本工艺条件下得到的负载型光催化剂，经XRD检测，其粒子平均尺寸小于10nm，主要晶型为锐钛矿相与金红石相的混合晶型。本文首次将负载在玻璃纤维布上的TiO₂光催化剂应用于H₂S恶臭气体的降解，并取得良好的效果。本研究的目的是，拓宽光催化剂TiO₂的应用范围，寻找一种经济、高效的无机类恶臭气体降解方法。通过研究发现，影响光催化剂降解低浓度H₂S气体效率的因素主要可分为两类：一是催化剂的制备工艺，如煅烧温度，负载层数以及催化剂改性等；二是气体环境的影响，如相对湿度，含氧量以及H₂S初始浓度。煅烧温度的变化主要影响了TiO₂光催化剂的粒子平均尺寸，对光催化剂的晶型成分构成影响不是太大，在不同的煅烧温度下得到的光催化剂晶型均为锐钛矿相与金红石相的混合晶型。其中500℃煅烧下得到的负载型光催化剂粒子平均尺寸较小为6.7nm，并且锐钛矿相含量也较其它煅烧温度得到的催化剂高，在本实验条件下，此工艺得到的光催化剂对H₂S降解效率最高；负载层数并非越多越好，而是存在一个合理值，当负载层数为3层时，实验效果较佳，亦经济。光催化剂的改性工作也得到研究，通过在制备过程中加入硝酸银的方法制得银沉积的负载型TiO₂光催化剂。XRD结果表明，银沉积并未明显改变光催化剂的晶型及粒子平均尺寸，实验结果亦表明，少量银参杂没有显著增加光催化剂对H₂S的降解效率，而加大参杂量使得降解效率下降。H₂O分子与纳米TiO₂光催化剂粒子的作用，使得相对湿度对催化剂降解H₂S有较大影响，当相对湿度为60％～80％时其降解效率较佳，最高可达97％；含氧量的变化影响了光催化剂对H₂S的降解效果，实验表明当氧气含量为21％，即正常大气水平时，效果较佳，增加含氧量可能造成光催化剂的活性位被占据，使得对H₂S的降解效率下降，故无需额外增加氧含量即可取得较高的降解效率，显示出了良好的经济性。此外，还对本实验研究条件下的TiO₂光催化降解负荷进行了研究，认为当H₂S初始浓度为300mg／m³左右，即污染负荷为34mgH₂S／mgTiO₂左右时，具有较高的降解效率。更多还原

【Abstract】 This paper studies how to make TiO₂ photocatalyst in the method of sol-gelatin （Sol-gel）, which fixed on the glass fiber, and degradation of H₂S in low concentration with the kind of photocatalyst in self-produced gas-solid reactor. This kind of fixed photocatalyst was tested by XRD, we found that the particle mean size of photocatalyst which was got on this technological conditions was smaller than 10nm, and the main crystal types were rutile and anatase, this kind of fixed photocatalyst has a good degradation effect on H₂S. In this study it is the first time that we applied the photocatalytst which was carried on glass fiber cloth to degradation of H₂S and achieved good results. The purpose of this study is to broaden the application range of TiO₂ photocatalyst, and seek a way which is economical and high-effect to decompose the inorganic smell substance.Study shows that the reasones which influence the applicated in degradation of the low concentration of H2S can be incorporated two ways. One of them is the technology of photocatalyst making, such as the temperature of calcining, the number of fixed time and the modification of the photocatalyst making. The other is the condition of gas, as relative humidity, O₂ content and the nitial consistency of H₂S.The change of the calcining temperature can influence the size of the fixed TiO₂ photocatalyst, and does few effect on the main crystal type. We can get the rutile and anatase in defferent calcining temperaters. The smallest size of TiO₂ photocatalyst is 6.7nm, which is calcined in the temperature of 500℃, and this kind of photocatalyst has more anatase than the other kind of photocatalyst. In our study, this kind of photocatalyst has the best efficiency in the degradation of H2S. The number of fixed time is not the more, the better, but has a better number, when the number of fixed time is 3, which can get a good efficiency, so does the economy.Modification of photocatalys has been researched, in the process of preparation we added AgNO₃. XRD indicated that doped Ag⁺ has not changed the crystal type and particle mean size of photocatalyst, the experiment showed that doped little Ag⁺ has not obviously enhanced the photocatalytic efficiency of H₂S, while doped much would decrease the efficiency.H₂O can react to the nami TiO₂ photocatalyst, which have great influence in the degradation of H₂S. A better effect, 97% at the highest can be got when 60%～80%. The diversification of O₂ content influence the result of photocatalytic, when the content reaches the natural level, as it is 21% which got the better efficiency, if increased the O₂ content, the more O₂ will occupy the active positiones of TiO₂ photocatalyst, which would reduce the efficiency. So we need do nothing to increase the O₂ content, but have a good effect on degradation of H₂S. This showed well economical, so it was not necessary to increase O₂ content we could got high efficiency.In addition, this paper studied the moderate load of H₂S degradation by TiO₂ photocatalyst, the result shows that when the initial consistency is about 300mg/m³, prompted by the occasion that the load is about 34mgH₂S/mg TiO₂, which can get a good effect.更多还原