影响CeY分子筛吸附脱硫性能因素的研究

通过液相离子交换法对NaY分子筛进行改性制得CeY分子筛，采用静态法考察了改性CeY分子筛中铈离子的负载量、焙烧温度、铈的价态、吸附水和分子筛骨架的结构对CeY分子筛吸附脱硫性能的影响。采用XRD和ICP分别对不同CeY分子筛的骨架结构及阳离子负载量进行了分析。结果表明，二次交换后,离子交换度达到88.9%，分子筛已达到交换平衡；最佳焙烧温度为500 ℃，温度过高会破坏分子筛的骨架结构；Ce(Ⅳ)Y的脱硫性能明显好于Ce(Ⅲ)Y；分子筛上的吸附水对硫化物的吸附能力也有较大的影响。     

稀土改性载铜Y分子筛吸附汽油中的噻吩

采用液相离子交换法制备了Cu+-Y分子筛和稀土改性Cu+-Y分子筛,以正己烷为溶剂,噻吩和苯分别作为硫化物和芳烃的代表形成模拟汽油体系,考察了它们的脱硫效果。结果表明,稀土增强了Cu+-Y分子筛对噻吩的吸附质量比。对只含噻吩的1号模拟汽油,稀土改性Cu+-Y分子筛对噻吩的穿透吸附质量比Cu+-Y分子筛增加了9.5%,稀土增强了Cu+-Y分子筛对噻吩的选择性;对含苯的2号模拟汽油,稀土改性Cu+-Y分子筛比Cu+-Y分子筛吸附噻吩的质量比增加了5.6%。稀土改性Cu+-Y分子筛脱硫剂易于再生,再生后仍有很好的吸附能力,可重复使用。     

Y/β(Na)复合分子筛改性及吸附脱硫性能

采用二次交换二次焙烧的方法对Y/β(Na)复合分子筛改性,得到Y/β(Ce)和Y/β(Ca)复合分子筛,对改性前后的分子筛结构进行XRD和ICP-MS表征,并考察其脱硫性能。结果表明:经液相离子交换后,Ce3+和Ca2+分别取代Na+进入到分子筛孔道中,且以高度分散的形态存在吸附剂上。改性后分子筛的脱硫吸附效果大大增强,在相同的条件下,Y/β(Ce)分子筛脱硫效果最佳。     

超声法制备Ce^4＋/13X分子筛的吸附脱硫性能

采用在离子交换过程中引入超声的方法制备了Ce4 /13X分子筛,考察了超声法对分子筛的制备及脱硫性能的影响,并考察了静态吸附条件对Ce4 /13X在低硫模型汽油(硫含量为23 mg/kg)中的脱硫性能影响。结果表明,超声法可显著缩短分子筛离子交换平衡的时间,提高离子交换度,且能有效地提高活性组分Ce在分子筛表面的含量,脱硫实验结果也显示吸附容量有明显的提高。常温常压,吸附时间为2.5 h,剂油质量比为0.0072的条件下,Ce4 /13X对噻吩的脱硫效果最好,吸附量为0.07653mmol/g,脱硫率可达到76.5%。Freundlich等温式能很好地关联噻吩在Ce4 /13X上的吸附平衡数据。450℃空气气氛中焙烧4 h的方法,可较好地再生Ce4 /13X。     

红外光谱法研究烯烃对Ce（Ⅳ）Y分子筛脱硫效果的影响

选取1-辛烯、1,5-己二烯、环己烯等作为模拟汽油中的烯烃模型化合物,采用FT-IR方法得到饱和吸附不同模拟油之后的Ce（Ⅳ）Y分子筛的红外光谱图,根据红外光谱信息研究烯烃对Ce（Ⅳ）Y分子筛选择性吸附脱硫性能的影响。研究发现,Ce（Ⅳ）Y分子筛阳离子和烯烃的双键发生了σ-π络合,从而跟与Ce（Ⅳ）Y存在SM作用的噻吩形成了竞争吸附。在含烯烃的模拟油中,由于烯烃和分子筛发生相互作用,占据了吸附剂的活性位,导致Ce（Ⅳ）Y分子筛的脱硫性能显著降低。     

Fe(Ⅲ)Y分子筛的制备及吸附脱硫性能

采用离子交换法对HY分子筛进行改性制备了Fe(Ⅲ)Y分子筛,采用X-射线衍射及N2吸附-脱附技术进行表征,并测试了其吸附性能。结果表明,离子交换法制备的Fe(Ⅲ)Y分子筛比表面积等结构参数较HY分子筛的略有降低,较好的保持了分子筛的晶体结构。在吸附时间2h,吸附温度70℃,剂油比为0.04时,Fe(Ⅲ)Y分子筛的吸附脱硫率可达到68.9%。分子筛再生性能测试表明,Fe(Ⅲ)Y分子筛重复使用4次后脱硫率下降了9.1%,说明催化剂稳定性及再生性能良好。     

红外光谱法研究烯烃对Ce(Ⅳ)Y分子筛脱硫效果的影响

选取1-辛烯、1,5-己二烯、环己烯等作为模拟汽油中的烯烃模型化合物,采用FT-IR方法得到饱和吸附不同模拟油之后的Ce(Ⅳ)Y分子筛的红外光谱图,根据红外光谱信息研究烯烃对Ce(Ⅳ)Y分子筛选择性吸附脱硫性能的影响。研究发现,Ce(Ⅳ)Y分子筛阳离子和烯烃的双键发生了σ-π络合,从而跟与Ce(Ⅳ)Y存在SM作用的噻吩形成了竞争吸附。在含烯烃的模拟油中,由于烯烃和分子筛发生相互作用,占据了吸附剂的活性位,导致Ce(Ⅳ)Y分子筛的脱硫性能显著降低。     

载锌NaY分子筛对FCC汽油吸附脱硫性能的影响

采用液相离子交换法将锌离子负载到NaY分子筛上,得到ZnY分子筛脱硫吸附剂。考察了锌离子负载浓度和不同焙烧温度对ZnY分子筛吸附脱硫性能的影响。研究脱硫实验中吸附温度和吸附空速对FCC汽油脱硫性能的影响,样品中的硫含量通过微库仑综合分析仪进行测定。结果表明,Zn(NO₃)₂负载浓度0.30 mol·L^-1、焙烧温度500 ℃、吸附温度30 ℃和吸附空速0.5 h^-1条件下对吸附脱硫性能最有利,脱硫率超过80%。考察两种方法对吸附剂进行再生。     

LiX沸石分子筛的铈离子改性研究

采用阳离子交换法对Li X沸石分子筛进行Ce⁽³⁺⁾改性,制得不同Ce(3+)改性,制得不同Ce⁽³⁺⁾交换量的Ce Li X沸石分子筛。通过XRD、SEM、BET、XRF对Ce Li X沸石分子筛进行表征,通过气体吸附仪测得了Ce Li X沸石分子筛在25℃下对氮气、氧气的吸附等温线。结果表明,Ce(3+)交换量的Ce Li X沸石分子筛。通过XRD、SEM、BET、XRF对Ce Li X沸石分子筛进行表征,通过气体吸附仪测得了Ce Li X沸石分子筛在25℃下对氮气、氧气的吸附等温线。结果表明,Ce⁽³⁺⁾通过离子交换法可以替换Li X沸石分子筛中的非骨架Li+,Ce(3+)通过离子交换法可以替换Li X沸石分子筛中的非骨架Li+,Ce⁽³⁺⁾的引入不会改变其原本的晶体结构,且能显著提高Li X沸石分子筛对O2/N2的吸附选择性。     

AgY吸附剂的吸附脱硫性能及竞争吸附研究

以NaY分子筛为载体,通过液相离子交换法制备了Ag改性的AgY分子筛,并对其进行了X射线衍射(XRD).原子吸收光谱(AAS)、N2吸附比表面积(BET)、X射线光电子能谱(XPS)和扫描电镜(SEM)等表征分析.以噻吩/石油醚体系为模型化合物,考察了吸附温度、吸附时间等吸附条件对吸附剂吸附性能的影响,结果表明吸附温度...     

Adsorptive Removal of Thiophene from Benzene by NaY Zeolite Ion-Exchanged with Ce(IV)

The commercial NaY zeolite with the Si/Al ratio of 5:1 was selected and modified for researching the adsorptive removal of thiophene from benzene. The zeolite was ion-exchanged in Ce(NO₃)₃ solution and then calcined in muffle to prepare the CeY sorbent. The results show that it is a suitable method to prepare the sorbent removing thiophene from benzene that NaY zeolite is ion-exchanged by cerium in Ce(NO₃)₃ solution. The desulfurization efficiency of CeY sorbent increases obviously comparing with NaY zeolite. The effects of the calcination temperature, calcination time, concentration of Ce(NO₃)₃ solution, ion-exchange time, and ion-exchange times on the desulfurization capacity of CeY sorbent were also studied. The results show that the optimal CeY sorbent can be obtained when NaY zeolite is ion-exchanged in 0.5 mol/L Ce(NO₃)₃ solution at 100°C for 4 h, calcined at 700°C for 2 h, and repeated the above steps two times. The results of XRD and BET characterization indicate that those preparation conditions mainly influence on the crystallinity, specific surface area of CeY sorbent. The best CeY sorbent can remove thiophene to 136.8 mg/L from 550.0 mg/L in thiophene-benzene solution at ambient temperature and pressure with the agent-liquid ratio of 1:16 (g/mL).     

用EDTA脱铝控制NaY沸石硅铝比的探讨

本文用EDTA作为NaY沸石的脱铝剂,制备出具有不同硅铝比的脱铝NaY沸石。考察了EDTA的加入量和pH对脱铝程度的影响。测定了脱铝沸石样品的IR吸收光谱、Cu~( )离子交换度和对水的吸附能力。结果表明,在pH=1～2条件下脱铝程度是与加入的EDTA量成线性关系,可根据需要控制脱铝NaY沸石的硅铝比。     

Properties of zeolite Y in various forms and utilization as catalysts or supports for cerium oxide in ethanol oxidation

Zeolite Y in sodium form (NaY) was synthesized using silica source from rice husk, transformed to ammonium form (NH₄Y), and calcined to convert to proton form (HY). The direct conversion of NH₄Y to HY resulted in loss of the zeolite crystallinity and lower surface area. Thus, the NH₄Y was further used in the preparation of cerium (Ce) catalysts. The NH₄Y was also treated with a basic solution in an attempt to generate mesopores but only site defects were likely formed. The supported Ce catalysts with good Ce dispersion were prepared by wetness impregnation of Ce precursor solution on NaY, NH₄Y, and base-treated NH₄Y. Upon calcination, the generated catalysts were notated as Ce/NaY, Ce/HY, and Ce/YB. In catalytic testing on ethanol oxidation at varying temperature in a continuous laboratory-scale fixed-bed reactor, all the zeolites gave low ethanol conversion at 100–300 °C. The catalytic activity significantly improved with the presence of Ce. The Ce/YB showed the higher ethanol conversion and CO₂ yield than Ce/NaY and Ce/HY probably because of the presence of more local site defects on the zeolite.     

Mn(Salen)/NaY的制备及其在β-蒎烯环氧化反应中的应用

用微波固相法制备了Mn(Salen)/NaY催化剂, 并对其催化β-蒎烯环氧化反应的性能进行了考察。FT-IR结果表明，微波固相方法和常规方法均能成功地将Mn(Salen)络合物包合于微孔分子筛NaY。与常规法制备的催化剂相比，微波固相法制备的Mn(Salen)/NaY催化剂对β-蒎烯环氧化具有很高的转化率和选择性，并且重复使用后催化活性变化不大。     

Fast tailoring of the acid–base properties in the NaX zeolite by cesium-exchange under microwave heating

NaX zeolite can show an acidic or basic behaviour depending on the degree of ion-exchange of sodium by cesium cations. The acid–base properties of the X zeolite are tunable by means of the cesium-exchange degree. This allows X zeolite to be prepared according to the needs of any determined reaction. Moreover, the cesium-exchange is carried out in a short period of time (5 min) when microwave radiation is used as the heat source. In addition, microwave heating decreases the volume of the ion-exchange solution. Only one cesium-exchange (28 cesium atoms per unit cell) under microwave heating was enough to annul the acid behaviour of the NaX zeolite in the toluene alkylation.     

高交换度BaX分子筛的制备及其吸附分离对二甲苯性能的研究

13X型分子筛经过钾离子交换后,再进行钡离子交换,多次交换后得到不同钡交换度的BaX分子筛。采用X射线衍射分析(XRD)、X射线荧光光谱分析(XRF)、比表面积物理吸附分析(BET)以及热失重/差热分析(TG/DTA)对样品进行表征,考察了不同钡交换度对分子筛吸附分离对二甲苯性能的影响。结果表明:钡离子交换后,分子筛孔道中的有效空间有所减少,平均孔径有所下降,但分子筛的晶型结构未受到明显影响;随着钡离子交换度的逐渐增大,BaX分子筛吸附分离对二甲苯的能力不断增强;钡离子交换度达到98.5%时,邻、间、对二甲苯的饱和吸附量分别为:254.1 mg/g、218.4 mg/g、376.9 mg/g,对/邻二甲苯分离系数、对/间二甲苯分离系数分别达到最大,为β(PX/OX)=1.48、β(PX/MX)=1.72。     

Design and synthesis of 3D ordered macroporous ZrO2/Zeolite nanocomposites

Zeolite NaY nanocrystals (20−50 nm) were hydrothermally grown on polyelectrolyte-coated three-dimensionally ordered macroporous (3DOM) activated zirconia. The zeolite nanocrystallites uniformly coated the macropore walls of 3DOM sulfated zirconia, but sulfate groups were lost during the hydrothermal reaction. 3DOM tungstated zirconia was found to be more stable in the strong basic environment of the zeolite precursor solution. Further, ion-exchange of zeolite NaY with ruthenium followed by hydrogen-reduction formed a composite of RuNaY and 3DOM activated zirconia. The presence of ruthenium was confirmed by X-ray photoelectron spectroscopy and the external shape of zeolite nanoparticles was maintained after ion-exchange, but the zeolite lattice fringes could not be observed by transmission electron microscopy after incorporation of reduced ruthenium. Although the catalytic activity of the materials has not yet been tested, these hierarchical nano- and microstructures bring multiple catalyst components (modified zeolite Y, a typical Fischer–Tropsch catalyst, and activated zirconia, an isomerization catalyst) together in intimate contact for potential multi-reaction processes.