铜、铈离子交换顺序对Y型分子筛吸附脱除苯中噻吩性能的影响

Effect of Ion-exchange Sequence of Copper and Cerium on the Performance of Y Zeolite for the Adsorption Removal of Thiophene from Benzene

【目的】利用双金属改性Y型分子筛对焦化苯中的噻吩进行深度脱除具有重要的意义。其中,金属离子交换顺序对分子筛脱硫性能的影响至关重要。【方法】采用Cu、Ce双金属,利用离子交换法制备出系列双金属改性吸附剂,采用静态吸附实验评价了吸附剂对苯中噻吩的脱除性能,并通过XRD、Py-FTIR、XPS、H2-TPR和N2吸脱附等手段表征了吸附剂的物化性质。【结果】结果表明,金属离子交换顺序会影响吸附剂的相对结晶度、离子交换度、金属含量以及L酸酸量。吸附剂的物化性质与脱硫性能进行关联发现,离子交换度越大,吸附剂的脱硫效率越高;同时吸附剂中Cu^(+)和Ce^(4+)含量越高,形成更多的L酸,其脱硫效率越高。利用双金属对Y型分子筛改性,先Ce后Cu进行交换时,金属Ce会对Cu的落位产生影响,Ce提高了Cu的还原性能。3种吸附剂脱硫效率由大到小为:CuCeY,CeCuY,Cu-CeY.CuCeY吸附剂的脱硫效率最高,可达97.3%,且其相对结晶度最高,离子交换度最大。此工作为高效脱硫吸附剂的制备起到了指导作用。

【Purposes】The bimetallic modified Y zeolite is of great importance for the deep removal of thiophene in coking benzene.The influence of metal ion-exchange sequence on the desulfurization performance of zeolite is crucial.【Methods】A series of bimetallic modified sorbents were prepared by ion-exchange with Cu and Ce.The desulfurization performance of sorbents in thiophene-benzene solutions was evaluated by static adsorption experiments.The physical and chemical properties of sorbents were analyzed by XRD,Py-FTIR,XPS,H2-TPR,and N2 adsorption and desorption techniques.【Findings】The results show that metal ion-exchange sequence affects the relative crystallinity,ion-exchange degree,metal content,and L acid amount of sorbent.The correlations between the physical,chemical properties and the desulfurization performance of sorbent indicate that the higher the ion-exchange degree,the higher the desulfurization efficiency of sorbent.Meanwhile,the more Cu^(+)and Ce^(4+) in the sorbent,the more L acid sites formed and the higher its desulfurization efficiency.When Y zeolite is exchanged by Ce first and then Cu,the metal Ce affects the location of Cu and improves reduction performance of Cu.The desulfurization efficiency order of sorbents is CuCeY>CeCuY>Cu-CeY.The desulfurization efficiency of CuCeY is the highest,reaching 97.3%,and its relative crystallinity is the highest and ion-exchange degree is the largest.This work serves as a guide for the preparation of high efficiency desulfurization sorbents.