Oxidative Capture of SOx and NOx by Activated Carbon Fiber

目前正在开发的ACF的具体应用是去除大气和烟道气中的SOx和NOx。脱硫的基本原理是以H_2SO_4的形式捕集SO_2。本文介绍了连续回收浓H_2SO_4水溶液的方法。NOx的脱除主要依靠NH_3还原成N_2或氧化成NO_2被碱性水溶液捕集。在环境温度下抑制大气中的湿度是一个问题。通过选择前驱体的活化程度和后热处理，ACF的疏水性能可以与其氧化活性相协调。酸雨是全球环境最受关注的问题之一。研究发现，在360 ℃左右，含氮量较高的ACF对1，2-二氯乙烷脱氯化氢反应具有较高的催化活性，表明ACF中的吡啶氮起刘易斯碱的作用。XPS表面研究提供了吡啶氮作为活性中心的一个证据。为了提高沥青基活性炭纤维的催化性能，采用与苯化学气相沉积法相同的方法，对沥青基活性炭纤维表面的吡啶化学气相沉积进行了研究。结果表明，催化剂中氮含量增加，催化活性提高。Pich基ACF催化活性低，寿命短。增重8%的活性炭纤维具有较高的催化活性和较长的使用寿命。与增重8wt%的ACF相比，增重16wt%的ACF显示出更高的初始活性，但寿命较短。这些结果提出了一种新的碳材料表面改性的方法，以创造活性位点。

Application particular to ACF now under development is removal of SOx and NOx in the atmosphere as well as flue gas. The basic principle of SOx removal is capture of SO_2 in the form of H_2SO_4. Continuous recovery of conc.aq.H_2SO_4 is now pursued. Removal of NOx relies basically on the reduction to N_2 with NH_3 or oxidation to NO_2 to be trapped by aq.bases. The inhibition of humidity in the atmosphere at ambient temperature is a problem. The hydrophobic properties of ACF can be compatible with its oxidation activity by selecting the precursor activation extent, and post heat-treatment.Acid rain is one of the most concerned problems for the global environment. Application of ACF to solve this problem is expected.The authers had found that ACF with larger amount of nitrogen content showed higher catalytic activity for dehydrochlorination of 1,2-dichloroethane into vinyl chloride at around 360ﾟC.It was suggested that pyridinic nitrogen included in the ACF worked as lewis base. Surface investigation by XPS provided one proof that pyridinic nitrogen worked as active site. For the aim of improvement of catalytic performances, pyridine CVD on the surface of pitch based ACF had examined by same way of benzene CVD as mentioned before. It was found that nitrogen content increased and catalytic activity raised. Pich based ACF showed low catalytic activity and short life time. On the other hand, the ACF of 8 wt% weight gain showed higher catalytic activity and long life time. The ACF of 16 wt% weight gain showed more higher initial activity, but resulted in shorter life time than the ACF of 8 wt% weight gain. These results propose a new method of surface modification of carbon materials to create active sites.