摘要
利用原位FTIR、XPS和GC MS等技术手段 ,研究了常温紫外光辐照下常压及真空状态中 ,CS2 的光氧化反应 .结果表明 ,常压及真空状态下CS2 光氧化反应的产物均为COS、SO2 、CO和CO2 ,反应均遵循表观一级反应动力学规律 ,但中间产物COS的浓度变化有较大的差异 .常压下COS浓度先迅速增大 ,然后减少 ;真空条件下COS浓度增加到常压下COS浓度的1/ 10后基本持平 ,然后逐渐减小 ,整个变化趋势缓慢 ;2种条件下CS2 的半衰期分别为 31. 6s和 39. 8s ,中间产物COS降解98%所需时间分别为 5 5min和 2 2min .在相同的光照条件下 ,O2 浓度的增加有助于CS2 光氧化反应的进行 .以CS2 光氧化中间产物COS为初始物的光氧化反应主要产物为CO2 和SO2 ,后者可以进一步被氧化为SO2 -4.适量增加O2 的浓度可以促进COS光氧化反应的进行 ,但O2 的浓度增加至一定程度后反应速率基本保持恒定 .以上结论对揭示CS2 和COS的源和汇以及全球S物质循环具有重要价值 .
With the radiation of UV light, the photooxidation of CS_2 was studied under ambient pressure and vacuum condition.By means of in-situ FTIR,XPS and GC-MS, it is confirmed that the products of the reaction are COS,SO_2,CO and CO_2. The reaction is apparent first-order. Under ambient pressure and vacuum condition the concentration of the intermediate product COS varies tremendously.Under ambient pressure the concentration of COS increases sharply and then decreases gently.While under vacuum condition COS rose only up to 1/10 that of the ambient pressure, and remained invariable until finally vanished slowly.Under ambient pressure and vacuum condition, the half life time of CS_2 was 31.6 s and 39.8 s, and it took 55 min and 22 min to degrade 98% of COS respectively.Oxygen promotes CS_2 photooxidation.The main products of the photooxidation of COS, which is an important intermediate of the photooxdiation of CS_2, are CO_2 and SO_2.In addition, SO_2 could be further oxidized into SO 2-_4.Increasing appropriate amount of oxygen could promote the photooxidation activity of COS. However, the rate constant remains invariable when the oxygen is overloaded.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2005年第2期45-49,共5页
Environmental Science
基金
国家自然科学基金资助项目 (2 0 3 770 0 8)
教育部归国留学人员基金
教育部博士点基金资助项目 (2 0 0 3 0 2 460 2 9)
