Synthesis and Characterization of Crystalline NaY-Zeolite from Belitung Kaolin as Catalyst for n-Hexadecane Cracking
Synthesis and Characterization of Crystalline NaY-Zeolite from Belitung Kaolin as Catalyst for n-Hexadecane Cracking
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DOI：
10.3390/cryst9080404
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发表时间：
2019-08-01
期刊：
影响因子：
2.7
通讯作者：
Hanna, John, V
中科院分区：
文献类型：
--
作者：
Krisnandi, Yuni K.;Saragi, Indah R.;Hanna, John, V
采用从别里洞天然高岭土中提取的铝酸盐和硅酸盐作为替代天然原料合成了Y型钠沸石晶体。在使用前，对天然高岭土进行预处理，得到破碎的偏高岭土和提取的二氧化硅。在100℃条件下，加入NaY凝胶（使用两种类型的NaY种子，分别由二氧化硅胶体和二氧化硅钠水制备），水热法合成21 h。对合成的沸石进行了表征，证实了用二氧化硅胶体种子制备的沸石与用前分析硅酸盐和铝酸盐源合成的NaY沸石具有更接近的结构相似性。因此，其余的NaY合成是使用胶体硅-NaY种子进行的。然后将NaY分子筛通过氨交换和煅烧转化为HY，以正十六烷为探针分子作为裂化催化剂进行测试。结果表明，偏高岭土和萃取二氧化硅制备的正十六烷转化率为58% ~ 64%，C-5-C-12收率为56% ~ 62%，选择性为98%。这项工作显示了利用高岭土作为合成晶体沸石的硅酸盐铝酸盐的替代来源，并获得廉价和环保的催化剂材料的潜力。
Crystalline sodium Y (NaY) zeolite has been synthesized using alternative natural source of aluminate and silicate, extracted from natural Belitung kaolin. Prior to use, the natural kaolin was pretreated to obtain fragmented metakaolin and extracted silica. Synthesis was conducted with the addition of NaY gel (two types of NaY seeds were used, prepared from colloidal sillica or sodium silica water) using hydrothermal method for 21 h at 100 degrees C. The characterization on the as-synthesized zeolites confirmed that the one prepared using colloidal silica-seed has closer structure similarity to NaY zeolite that was synthesized using pro analysis silicate and aluminate sources. Thus, the rest of the synthesis of NaY was carried out using colloidal silica-NaY seed. The NaY zeolites then were converted to HY, through ammonium-exchange followed by calcination, to be tested as cracking catalysts using n-hexadecane as a probe molecule. It shows that HY from metakaolin and extracted silica gives high performance, i.e., n-hexadecane conversion of 58%-64%, also C-5-C-12 percentage yield and selectivity of 56%-62% and 98%. This work has shown the potential to utilize kaolin as alternative silicate aluminate sources for crystalline zeolite synthesis and to obtain inexpensive and environmentally friendly catalyst materials.