类水滑石衍生氧化物催化水解HCN及其热力学分析

摘要

It is critical to develop new-style hydrolysis catalysts of HCN for the deep purification of HCN.Cu-Al hydrotalcite-like (LDH) catalysts were prepared by single titration method and double titration method,and the effect of synthetic methods for the preparation of LDH structure was explored.It could be obviously seen from XRD characterization results that the crystal shapes of catalysts synthesized by single titration method were better than double titration method.A series of hydrotalcite-derived oxide (LDO) catalysts with different composite metal ions were synthesized by single titration method,and the order of their activities for hydrolysis of HCN was Cu-Al LDO ＞ Zn-Al LDO ＞ Ni-Al LDO ＞ Mg-Al LDO ＞ Co-Al LDO.Based on thermodynamic computation,the possible reaction pathways and influencing factors of Cu-Al LDO catalyzing hydrolysis of HCN were also discussed.The results show that the hydrolysis reaction of HCN can generate CO and NH3 at the range of 0-600 ℃C,and HCN can react with O2 or CO to generate H2 O,which can promote HCN hydrolysis and improve the removal efficiency of HCN.Nevertheless,the presence of CO and NH3 may lead to carbon deposition and the formation of Cu,which could reduce the service life of the catalyst.%开发新型HCN水解催化剂是深度净化HCN的关键,文中采用单滴定法和双滴定法制备了Cu-Al类水滑石(LDH)催化剂;并探究了合成方法对所制备LDH结构的影响,XRD表征结果发现单滴定法制备的催化剂晶型更好.采用单滴定法制备了不同复合金属离子的类水滑石衍生氧化物(LDO)催化剂,HCN催化水解活性顺序依次为:Cu-Al LDO＞ Zn-Al LDO＞ Ni-Al LDO＞ Mg-Al LDO＞ Co-Al LDO.基于热力学计算探讨了Cu-Al LDO催化水解HCN的可能途径及影响因素.结果表明:在0-600℃温度范围内,HCN水解可生成CO和NH33HCN可与O2和CO反应会生成H2O,促进HCN水解,提高HCN的脱除效率;CO和NH3的存在有可能造成积碳和铜单质生成,导致催化剂使用寿命降低.