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...     

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。     

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。     

改性NaY分子筛吸附脱硫性能的研究

以NaY分子筛为载体,采用液相离子交换法制备了一系列用于燃料油脱硫的负载金属离子的改性分子筛吸附剂.结果表明,AgY具有最高的硫容,其次是CuY、NiY、CeY、ZnY,硫化物吸附量顺序为:噻吩＞苯并噻吩＞二苯并噻吩.通过正交实验优化了Y分子筛的制备工艺,并对实验数据进行了方差分析,得到了最佳制备工艺条件:活性组分为A...     

改性吸附剂的制备及汽油吸附脱硫性能评价

以微孔-介孔复合分子筛ZSM-MCM为载体,采用浸渍法制备了Fe型吸附剂Fe/ZSM-MCM。结果表明其活性组分为Fe2O3,负载型吸附剂的适宜制备条件为：浸渍液浓度0.2 mol/L,浸渍时间10 h,干燥温度100℃,550℃焙烧4 h。最佳吸附条件：常温、常压,吸附时间1 h,剂油质量比1︰60,在该条件下吸附剂的饱和吸附量为36.46 mg/g。     

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。     

碱土金属元素Mg对Cu~+-13X分子筛吸附脱硫性能的影响

以13X分子筛为载体,采用液相离子交换法制备了Cu+-13X吸附剂和负载碱土金属元素Mg的Mg2+/Cu+-13X吸附剂,并利用XRD,XRF,ESEM和激光拉曼光谱仪(HR-800)等手段对所制备的吸附剂进行了表征。以含有噻吩和2-乙基噻吩的正己烷溶液为模拟燃料油,分别从静态吸附、吸附动力学两方面研究了两种吸附剂的脱硫性能,采用Langmuir模型和竞争吸附的Langmuir模型对单、双组分硫化物的静态吸附平衡数据进行拟合;采用Crank单孔扩散模型对吸附动力学数据进行拟合。结果表明,当Mg2+/Cu+-13X吸附剂中Mg的质量分数为3.35%时,吸附性能最佳;实验数据与模型吻合均很好,计算得到了Mg2+/Cu+-13X吸附剂对噻吩和2-乙基噻吩单组分的最大吸附量分别为140.7mg?g?1和183.8 mg?g?1,较Cu+-13X吸附剂对噻吩和2-乙基噻吩单组分的最大吸附量(130.2 mg?g?1和173.6 mg?g?1)分别提高了8.1%和5.9%,Mg2+/Cu+-13X双金属吸附剂的脱硫效果明显好于Cu+-13X吸附剂;负载的Mg2+作为一种助剂,使分子筛形貌分布更加均匀规整,并且增加了吸附剂的Lewis酸含量,使其还原性增强,吸附性能提高。     

稀土改性13X分子筛的表征与脱硫性能评价

采用离子交换法制备了Ce/13X、La/13X及La-Ce/13X分子筛吸附剂。通过X射线衍射、N2物理吸附、扫描电子显微镜、傅里叶红外光谱等手段对吸附剂进行表征,考察对比了三种吸附剂的动态吸附性能以及温度和流速对吸附性能的影响,并对吸附剂进行再生。结果表明,稀土离子改性后的13X分子筛的比表面积、孔体积出现一定程度的下降,分子筛结晶度降低但并未改变其骨架结构。La的载入与Ce具有协同作用,使得双金属改性的La-Ce/13X分子筛在脱硫吸附性能上较单金属改性的分子筛有明显的提高。常温下,空速为6h-1,La-Ce/13X分子筛能够将起始浓度为0.2mg/g的模拟油脱除至0.01mg/g,经过7h后穿透,穿透硫容为6.118mg/g,吸附剂经过氮气气氛300℃焙烧2h后,可较好的再生。     

AgCo13X改性分子筛的制备与吸附脱硫性能

采用液相离子交换法制备了以金属离子Co2+和Ag+共同改性的AgCo13X分子筛吸附剂,并用XRD、NH3-TPD、BET和TG等技术对其结构进行表征。在模拟柴油中考察了吸附剂对二苯并噻吩(DBT)的脱硫性能。结果表明:AgCo13X分子筛的脱硫性能优于单一离子改性的Co13X和Ag13X分子筛;而Co13X和Ag13X分子筛的脱硫性能又明显高于未改性的13X分子筛。当Ag+离子交换浓度为0.1 mol/L时制备的Co2+和Ag+共同改性的AgCo13X分子筛具有最好的脱硫性能,其脱硫率为99.91%。剂油比为0.02 g/mL,当吸附时间为1 h即可达到吸附平衡;吸附剂具有良好的稳定性和再生性,再生后的脱硫率达到98.21%。     

改性ZSM-5-MCM-41复合分子筛的制备及脱硫性能研究

采用等体积浸渍法对ZSM-5-MCM-41复合分子筛进行改性,物性分析表明改性后合成的复合分子筛兼具微孔和介孔结构,活性组分为Co3O4和NiO,比表面积为626 m2/g.吸附脱硫实验表明合成材料在负载量为10％,浸渍时间12 h,吸附用量为0.08 g/mL,反应温度为25℃时的脱硫率可达96.78％.     

Study on Adsorption and Diffusion in Zeolite

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Adsorption of 2,4,6‐Trinitrotoluene on MFI Zeolite

2,4,6‐Trinitrotoluene (TNT) was adsorbed onto all silica MFI zeolite. These TNT doped zeolite samples were examined using Fourier Transform Infrared Spectroscopy (FTIR) and X‐ray Diffraction (XRD). Results indicate that, using FTIR with an Attenuated Total Reflection (ATR) accessory, mass loading percentages as low as 2.5 mass percent TNT in zeolite are detectable. It was also observed that adsorption of TNT onto MFI did not suppress the IR absorbing vibrations of TNT. TNT doped zeolite samples were washed, using vacuum aspiration, with water and acetone, both of which stripped the TNT from the zeolite samples, indicating that the adsorption of TNT onto MFI zeolite is a physisorption, rather than chemisorption, phenomenon. Finally, a lack of strain‐induced peak broadening from XRD studies indicate that TNT does not enter the zeolitic pore structure, rather, it is adsorbed onto the zeolite surface.     

煤系高岭土水热合成干燥用13X型沸石分子筛

研究以内蒙古鄂尔多斯煤系高岭土为原料,水热合成干燥用13X型沸石分子筛。采用单因素条件实验,考察了晶化时间、碱投加量、胶化温度、胶化时间、晶种投加量等制备条件对合成13X型分子筛的影响。通过静态饱和吸水量测定,RD、IR和SEM等表征手段对产品进行表征。发现最佳的反应条件为：合成液中晶种投加量为2%和碱投加量R[n（Na2O）/n（H2O）]控制在5.3,在65℃下胶化3h、然后在100℃下晶化时间24h,此时合成的X型分子筛的静态饱和吸水量为33.47%,合成晶体的外形为八面体晶型,而且形状规则、大小均匀、晶体棱角也比较清晰。     

Dealuminated Y Zeolite for Water-Driven Adsorption Heat Pumps: Hydrothermal Stability

Silica gel or zeolites AlPO-5 and SAPO-34 are recommended as adsorbents in water-driven heat pumps because of their selective water uptake. Secondary energy, like solar energy, can be used for regeneration of loaded adsorbers. In case of the availability of only low energy levels, the use of dealuminated Y zeolite (DAY) is the better choice because of the infinitely variation of its hydrophilic properties by tailoring of the framework Si/Al ratio. Actual data on the hydrothermal stability of DAY are lacking. Thus, we report on the long-term behavior of DAY zeolites with different Si/Al ratios.     

Adsorption removal of thiophene and dibenzothiophene from oils with activated carbon as adsorbent: effect of surface chemistry

Commercial coconut-based activated carbons (AC), before and after being treated using 65 wt% HNO₃ at different temperatures (termed as AC–Hs), were used as adsorbents to remove thiophene (T) or dibenzothiophene (DBT) from model oils. The fresh AC sample and all of the AC–Hs samples were characterized by Boehm titration, Fourier-transform infrared spectroscopy, and thermal analysis, which yield the information of the surface chemistry properties of the carbon materials. The results show that in comparison to the fresh AC sample, the quantity of oxygen-containing functional groups on the surface of AC–Hs samples increases as the pretreatment temperature of the fresh AC sample increases. The adsorption capabilities of the AC samples for removal of T and DBT from model oils were evaluated in a batch-type reactor. It has been found that the refractory DBT can be removed easily over the untreated commercial AC with the removal efficiency even being higher than that of T. In the case of acid modified AC–Hs samples, the efficiency for removal of T has been greatly improved, but this is not the case for the removal of DBT. The possible mechanism for adsorption removal of T and DBT over activated carbons is discussed in terms of the quantity of surface oxygen-containing functional groups of adsorbents and the chemical structure of sulfur compounds. The effect of olefin (1-octene) and aromatic hydrocarbons (benzene) in the model oils on the selective adsorption DBT over AC is also evaluated, revealing that in the case of DBT, the competitive adsorption is involved in the process, and the removal efficiency levels off at a level over 80%.     

硅沸石—1制备方法改进及性能研究

本文阐述了一种制备憎水性分子筛—硅沸石-1的新工艺。测定了这种分子筛气相吸附正己烷、乙醇和水的平衡量,以及液相吸附乙醇和水的平衡量,表明这种分子筛具有良好的亲有机和憎水的吸附性能。通过液相吸附透过曲线实验,表明液相吸附乙醇过程为固膜扩散控制。经Cu~(2+)浸渍的这种分子筛,可使甲醇脱氢制甲醛的转化率的选择性大为提高。     

Co-BTC脱除噻吩性能研究

基于溶剂热法合成出金属有机骨架材料Co-BTC,通过XRD、IR表征其结构。采用固定床吸附穿透实验,考察了不同的空速条件及溶解水对Co-BTC吸附分离噻吩的影响,并用甲苯溶剂洗涤进行吸附剂再生。结果表明,Co-BTC对模型油中噻吩的穿透容量及饱和吸附量分别为0.98%,2.05%(wt);Co-BTC在含溶解水和纯模型油中硫的饱和容量分别是1.50%,2.05%,饱和吸附容量降低了27%,运用分子筛分层填装吸附柱技术能将Co-BTC的饱和吸附容量提高到2.02%;再生的吸附剂对模型油中噻吩硫的饱和吸附容量为2.02%,再生率达到99%。     

NaOH改性沸石吸附地下水中铁锰效能研究

为了提高沸石对铁锰的吸附性能，利用3种不同改性剂对天然沸石进行改性比较对铁锰的去除效果。通过NaOH改性沸石除铁锰的静态吸附试验研究，考察改性沸石对铁锰的去除效果。结果表明NaOH改性沸石对铁锰的去除效果优于NaCl和HDTMA改性沸石对铁锰的去除效果，NaOH改性沸石的投加量、改性沸石的对铁锰的吸附时间、原水的pH值等因素对铁锰的去除效果有较大的影响，最佳投加量为50g/L，最佳吸附时间为120min，最佳pH值为中性偏酸性或者偏碱性且pH值〈8时，对铁锰的吸附规律较好的符合Langmuir吸附等温式。NaOH改性沸石对铁去除率可达83．09％，对锰的去除率为49．65％。经过改性，沸石对铁锰的去除率和吸附容量都有了较大的提高。     

Kinetic Studies of Phytosterol Adsorption on Zeolite

Abstract

Equilibrium isotherms of sterol adsorption on zeolite show the characteristics of irreversible equilibrium adsorption. First order and second order surface adsorption control mechanisms as well as micropore diffusion control model failed to satisfactorily describe the kinetics of sterol adsorption on zeolite. From the analysis of adsorption data, it was found that macropore diffusion control model satisfactorily describes the kinetics of sterol adsorption on zeolite. The effect of temperature on the diffusivity during adsorption was found to conform to the Eyring equation. It was shown that a change in temperature has a negligible effect on the selectivity of sterol adsorption on zeolite.