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采用PASCA、NMR、IR等技术研究NaY沸石钙交换过程及机理.结果表明,NaY沸石中引入钙离子(钙交换度>20%时)并在水蒸气气氛中焙烧,可导致沸石骨架中产生非骨架铝(NFAl)和大量平均孔直径达到18nm的二次孔道(SP).产生最大数量的NFAl和产生最多SP的最佳交换度为60%,此时CaNaY沸石中含有最大量的B酸和最大量的L酸.结果还表明,在钙交换过程中,钙必须以Ca~(2+)离子的形式交换在NaY沸石骨架上,因此,交换过程中控制好浆液的pH值是必要的,最佳pH值为5.5.CaNaY沸石的最佳水热处理温度为550℃.
The calcium exchange process and mechanism of NaY zeolite were studied by PASCA, NMR and IR.The results showed that calcium ions (calcium exchange degree> 20%) were introduced into NaY zeolite and calcined in water vapor atmosphere, Skeleton aluminum (NFAl) and a large number of secondary channels (SP) with an average pore diameter of 18 nm.The optimum exchange degree for producing the maximum amount of NFAl and producing the most SP is 60% when CaNaY zeolite contains the maximum amount of B acid and The maximum amount of L acid.The results also show that in the calcium exchange process, calcium ions must be in the form of Ca2 + exchange NaY zeolite skeleton, so the exchange process to control the pH value of the slurry is necessary, The optimum pH value is 5.5. The optimum hydrothermal temperature of CaNaY zeolite is 550 ℃.