AgY分子筛的制备及其吸附脱除模拟燃料中吡啶的性能

PREPARATION OF AgY MOLECULAR SIEVES AND ITS ADSORPTION PERFORMANCE OF PYRIDINE IN SIMULATED FUELS

采用离子交换法制备了AgY分子筛,利用X射线衍射对AgY分子筛进行了表征,并分别以NaY和AgY分子筛为吸附剂进行模拟燃料中吡啶的静态吸附脱除试验。结果表明,AgY分子筛的吸附脱氮能力强于NaY分子筛,且AgY分子筛较适宜的吸附脱氮条件为:当模拟燃料用量为15 mL时,分子筛用量0.2 g、吸附温度333 K、吸附时间40 min。采用Materials Studio软件建立了NaY和AgY分子筛团簇模型,模拟计算了吡啶分子在NaY和AgY分子筛团簇上的吸附能及其与活性中心的距离,结果表明,吡啶与AgY分子筛活性中心的距离小于NaY分子筛,故AgY分子筛的吸附性能好于NaY分子筛。吸附等温线研究结果表明,AgY分子筛对模拟燃料中吡啶的吸附行为符合Langmuir-Freundlich混合模型;吸附热力学和动力学研究结果表明,此吸附反应是自发进行的吸附熵增过程;在333 K温度条件下,此吸附过程符合准二级动力学模型。

AgY zeolite was prepared by ion exchange method,and characterized by X-ray diffraction.NaY and AgY zeolites were used to the static adsorptive denitrification of pyridine in simulated fuel.The results showed that the adsorption and denitrification capacity of AgY zeolite was better than that of NaY zeolite,and the suitable adsorption and denitrification conditions of AgY zeolite were as follows:an amount of simulated fuel of 15 mL,an amount of AgY zeolite of 0.2 g,an adsorption temperature of 333 K,and an adsorption time of 40 min.The cluster models of NaY and AgY zeolite were established by using Materials Studio software,and the adsorption energy of pyridine on NaY and AgY zeolite and the distance between pyridine and the active center were calculated.The distance between pyridine and the active center of AgY zeolite was smaller than that of NaY zeolite,so the adsorption performance of AgY zeolite was better than that of NaY zeolite.The adsorption behavior of pyridine on AgY zeolite confirmed to the Langmuir-Freundlich mixed model.The adsorption thermodynamics and kinetics of pyridine on AgY zeolites were investigated.The adsorption reaction is a spontaneous process of adsorption entropy increase,and the adsorption process accords with the quasi-second-order kinetic model at the temperature of 333 K.