摘要
Y型沸石耐酸性能较弱,直接用无机酸使其脱铝时,晶体结构易遭破坏.本文研究了无机酸与配合剂共同作用下Y型沸石的脱铝. 将温州催化剂厂产NaY用N_4Cl交换两次,制备出交换度约为75％的(NH_4Na)Y.(NH_4Na)Y以在水溶液或醋酸铵缓冲液中预热到所需温度,不断搅拌下滴加脱铝剂,并反应一段时间.反应停止后,用热水洗涤产物数遍,经离心分离,脱铝沸石在120℃烘干,备用.沸石的组分分析采用湿法化学法.取微量沸石与KBr混合后压片。
Faujasite is unstable in aqueous acidic solution .When it is de-aluminated with mineral acid, its crystal structure is easy to be destroyed.Using NH4Ac as buffer to control pH=6, NH4NaY was dealu-minated with HF formed by mixing HC1 and NH4 F, it was found that the zeolite still kept high crystallinity even 50% of framework aluminium were removed.By adding HC1 to the aqueous mixture of NH4 F and NH4 -NaY at 85C and keeping pH = 4.5, the zeolite kept also high crystallinity after 50% Al removal.During the reaction, some Si4+ entered the 'hydroxyl nests' produced by dealumination, so the value of a0 of the dealuminated Y zeolite lain between the values of the zeolites dealu-minated with EDTA and (NH4)2SiF6
基金
国家自然科学基金
关键词
Y型沸石
脱铝
盐酸
氟化铵
Y zeolite,dealuinitiation ,hydrochloric acid ,ammonium fluoride
