摘要
采用晶化培育法制备了L沸石纳米晶簇,以其作为前驱体,并以3-三甲基甲硅烷基丙基十六烷基二甲基氯化铵(TPHAC)为模板剂,合成了微孔-介孔多级孔道L沸石(MeLTL沸石).通过X射线衍射(XRD)、氮气吸附-脱附、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、27Al固体魔角核磁(27AlMASNMR)和吡啶傅立叶变换红外(Py-FTIR)等方法对MeLTL沸石进行了表征.研究结果表明,MeLTL沸石是由L沸石纳米晶簇自组装形成的,并具有介孔孔道和L沸石的微孔结构以及适宜的酸量与酸强度,其比表面积和孔体积分别高达611m2.g-1和0.696cm.3g-1.将MeLTL沸石作为添加剂引入柴油加氢脱硫催化剂载体中,并与添加L沸石、Al-MCM-41和仅以γ-Al2O3为载体的催化剂进行比较,其脱硫性能为最佳,经加氢后的柴油硫含量仅为9.3μg.g-1,脱硫率达99.3%.
Zeolite MeLTL with a micro-mesoporous composite pore structure was synthesized by using nanocrystal clusters of zeolite L prepared by the crystallization nurturing method as a precursor and [3-（trimethoxysilyl）propyl] hexadecyldimethylammonium chloride （TPHAC） as the organic mesopore directing surfactant. Several techniques including X-ray diffraction （XRD）, nitrogen adsorption-desorption, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, ^27Al magic angle spinning nuclear magnetic resonance （^27Al MAS NMR）, and Fourier transform infrared spectroscopy of pyridine adsorption （Py-FTIR） were used to characterize the samples. Results show that zeolite MeLTL is formed by the self-assembly of zeolite L nanocrystals, and it has bimodal pore distributions with a stepwise mesoporous structure and the microporous structure of zeolite L. The BET surface area and the pore volume increased significantly and were 611 m^2· g^-1 and 0.696 cm^3·g^-1, respectively. Zeolite MeLTL was composed of zeolite L units and this was responsible for the adequate surface acid amount and acid strength. As a result, the pore diffusion ability and the catalytic performance of zeolite MeLTL are enhanced by the improvement in textural properties. For diesel hydrodesulfurization, the catalyst introduced zeolite MeLTL gave better hydrodesulfurization activity compared to the catalysts introduced zeolite L or Al-MCM-41 or used bare T-Al2O3 as a support. The sulfur content of diesel oil after hydrotreatment was 9.3 μg·g^-1 and the desulfurization rate was 99.3%.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2010年第2期378-384,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20876174)
中国石油天然气股份有限公司科学研究与技术开发(2008A-3801)资助项目~~
关键词
加氢脱硫
L沸石
介微孔复合孔道
TPHAC
柴油
加氢催化剂
Hydrodesulfurization
Zeolite L
Micro-mesoporous composite structure
TPHAC
Diesel oil
Hydrogenation catalyst
