低成本多级孔TS-1的制备及其氧化脱硫性能
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摘要
利用碱处理、酸碱复合处理的方法制备多级孔钛硅(TS-1)分子筛。运用XRD、XRF、SEM和N2吸附等表征手段对其做了物性分析。以氧化脱除噻吩和苯并噻吩为探针反应对其氧化性能做了评价。结果表明:碱处理、酸碱复合处理均在未破坏分子筛拓扑结构的同时形成介孔孔道。样品进行碱处理脱硅的同时导致骨架钛物种脱落,非骨架钛含量增加,造成氧化剂H_2O_2的无效分解,催化性能略有降低。酸碱复合处理能有效洗掉碱处理引入的钠离子和非骨架钛,使得介孔孔道更加通畅,活性钛物种骨架钛相对含量增加,有效提高了分子筛的催化活性,尤其对大分子苯并噻吩脱除率由49%提高至71%。
The means of alkali treatment and alkali-acid-alternating treatment were employed to synthesize low-cost hierarchical porous titanium silicon molecular sieve(TS-1).The chemicophysical properties of the catalyst were characterized by XRD,XRF,SEM and N2 adsorption etc..The oxidation of thiophene and thianaphthene was selected as probe reaction to evaluate the oxidation property of TS-1.The results indicated that both alkali treatment and alkali-acid-alternating treatment could contribute to the generation of mesoporous structure without degradation of TS-1 framework.However,the alkali-treated desilicication of TS-1 would lead to the leak of framework titanium.The increased content of non-framework titanium inhibited the effective decomposition of hydrogen peroxide,resulting in the lower catalytic performance.On the contrary,alkali-acidalternating treatment could remove sodium ions and non-framework titanium remarkably.The content of active titanium species,framework titanium increased,which improved the catalytic activity of TS-1 dramatically.On the removal of bulky benzothiophene,the removal rate was raised from 49% to 71%.
The means of alkali treatment and alkali-acid-alternating treatment were employed to synthesize low-cost hierarchical porous titanium silicon molecular sieve(TS-1).The chemicophysical properties of the catalyst were characterized by XRD,XRF,SEM and N2 adsorption etc..The oxidation of thiophene and thianaphthene was selected as probe reaction to evaluate the oxidation property of TS-1.The results indicated that both alkali treatment and alkali-acid-alternating treatment could contribute to the generation of mesoporous structure without degradation of TS-1 framework.However,the alkali-treated desilicication of TS-1 would lead to the leak of framework titanium.The increased content of non-framework titanium inhibited the effective decomposition of hydrogen peroxide,resulting in the lower catalytic performance.On the contrary,alkali-acidalternating treatment could remove sodium ions and non-framework titanium remarkably.The content of active titanium species,framework titanium increased,which improved the catalytic activity of TS-1 dramatically.On the removal of bulky benzothiophene,the removal rate was raised from 49% to 71%.
引文
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[8] Caicedo-Realpe R,Pérez-Ramírez J.Mesoporous ZSM-5 zeolites prepared by a two-step route comprising sodium aluminate and acid treatments[J].Microporous&Mesoporous Materials,2010,128(1/2/3):91-100.
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[11]张义华,郭新闻,王祥生,等.TS-1分子筛中非骨架钛物种(TiO2)x对丙烯环氧化反应的影响[J].石油学报,2000,16(5):41-46.
[12] Xiong G,Jia Q,Cao Y,et al.The effect of acid treatment on the active sites and reaction intermediates of the low-cost TS-1 in propylene epoxidation[J].Rsc.Advances,2017,39(7):24046-24054.
[13]左轶.钛硅分子筛的合成、改性及其催化丙烯环氧化性能的研究[D].大连:大连理工大学,2013.
[14]曾小军,张晓昕,宗保宁.负载型吸附剂用于柴油吸附脱硫的研究[J].无机盐工业,2005,37(10):52-55.
[2]任容欣,宋万仓,刘冠锋,等.多级孔钛硅分子筛的制备及应用进展[J].分子催化,2017(6):594-604.
[3] Ogura M,Shinomiya S Y,Tateno J,et al.Alkali-treatment techniqueNew method for modification of structural and acid-catalytic properties of ZSM-5 zeolites.[J].Appl.Catal.A,2001,219(1/2):33-43.
[4]陈艳红,韩东敏,崔红霞,等.多级孔ZSM-5沸石分子筛的制备研究进展[J].无机盐工业,2017,49(7):3-6.
[5] Verboekend D,Pérez-Ramírez J.Design of hierarchical zeolite catalysts by desilication[J].Cat.Sci.Technol.,2011,1(6):879-890.
[6] Groen J C,Moulijn J A.Desilication:On the controlled generation of mesoporosity in MFI zeolites[J].Journal of Materials Chemistry,2006,16(22):2121-2131.
[7]史晓杰,邢侃,樊红超,等.ZSM-5分子筛的合成与改性研究进展[J].无机盐工业,2016,48(2):6-8.
[8] Caicedo-Realpe R,Pérez-Ramírez J.Mesoporous ZSM-5 zeolites prepared by a two-step route comprising sodium aluminate and acid treatments[J].Microporous&Mesoporous Materials,2010,128(1/2/3):91-100.
[9] Tsai S T,Chao P Y,Tsai T C,et al.Effects of pore structure of posttreated TS-1 on phenol hydroxylation[J].Catal.Today,2009,148(1/2):174-178.
[10] Silvestre-Albero A,Grau-Atienza A,Serrano E,et al.Desilication of TS-1 zeolite for the oxidation of bulky molecules[J].Journal of Analytical Chemistry,2004,59(1):77-85.
[11]张义华,郭新闻,王祥生,等.TS-1分子筛中非骨架钛物种(TiO2)x对丙烯环氧化反应的影响[J].石油学报,2000,16(5):41-46.
[12] Xiong G,Jia Q,Cao Y,et al.The effect of acid treatment on the active sites and reaction intermediates of the low-cost TS-1 in propylene epoxidation[J].Rsc.Advances,2017,39(7):24046-24054.
[13]左轶.钛硅分子筛的合成、改性及其催化丙烯环氧化性能的研究[D].大连:大连理工大学,2013.
[14]曾小军,张晓昕,宗保宁.负载型吸附剂用于柴油吸附脱硫的研究[J].无机盐工业,2005,37(10):52-55.