The efficient separation of hexane isomers from the light naphtha fraction is a significant challenge in the petrochemical industry. 5A zeolite adsorbent is used commercially to sieve alkane isomers. In this study, 5A zeolites were synthesized using a low-cost natural clay mineral precursor, i.e. palygorskite (PAL), with the addition of crystallization directing agent (CDA). By varying the mass ratio of CDA/deionized water, 5A zeolites were obtained as CDA-5%, CDA-7.5%, and CDA-10%. All products were submicron particles with an average particle size of 400–800 nm. A sieving test of CDA-induced 5A zeolites was carried out on hexane adsorbates including n -hexane ( n HEX), 2-methylpentane (2MP), and 3-methylpentane (3MP). According to vapor-phase batch adsorption experiments, a significant equilibrium amount (0.149 g/g) of n HEX and only 0.0321 g/g 2MP and 0.0416 g/g 3MP were adsorbed on the 5A zeolite product with CDA-5%. The dynamic adsorption performance of 5A zeolite (CDA-5%) was evaluated by breakthrough curves of binary mixtures of n HEX/2MP and n HEX/3MP. Palygorskite 5A (PAL 5A) zeolite achieved maximum dynamic adsorption capacities of n HEX (0.16 g/g in both cases) at 200°C and 1.2 MPa total pressure. This work provided an economic alternative for the synthesis of 5A zeolites using natural clay minerals instead of chemical raw materials.

中文翻译：

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坡缕石直接合成5A沸石：结晶导向剂对己烷异构体分离性能的影响

从轻石脑油馏分中有效分离己烷异构体是石化行业的一项重大挑战。5A 沸石吸附剂在商业上用于筛分烷烃异构体。在这项研究中，5A 沸石是使用低成本的天然粘土矿物前体，即坡缕石 (PAL)，并添加结晶导向剂 (CDA) 合成的。通过改变CDA/去离子水的质量比，得到CDA-5%、CDA-7.5%和CDA-10%的5A沸石。所有产品均为亚微米颗粒，平均粒径为 400-800 nm。对包含正己烷 (n HEX)、2-甲基戊烷 (2MP) 和 3-甲基戊烷 (3MP) 的己烷吸附物进行了 CDA 诱导的 5A 沸石的筛分试验。根据气相批量吸附实验，n HEX 的显着平衡量 (0.149 g/g) 和仅 0。0321g/g 2MP和0.0416g/g 3MP吸附在CDA-5％的5A沸石产品上。5A沸石(CDA-5%)的动态吸附性能通过n HEX/2MP和n HEX/3MP的二元混合物的穿透曲线评价。坡缕石 5A (PAL 5A) 沸石在 200°C 和 1.2 MPa 总压力下实现了 n HEX 的最大动态吸附容量（两种情况下均为 0.16 g/g）。这项工作为使用天然粘土矿物代替化学原料合成 5A 沸石提供了一种经济的替代方法。在两种情况下均为 16 g/g）在 200°C 和 1.2 MPa 总压力下。这项工作为使用天然粘土矿物代替化学原料合成 5A 沸石提供了一种经济的替代方法。在两种情况下均为 16 g/g）在 200°C 和 1.2 MPa 总压力下。这项工作为使用天然粘土矿物代替化学原料合成 5A 沸石提供了一种经济的替代方法。