航空煤油在不同价态金属离子交换介孔材料上的深度吸附脱硫

采用离子交换法,将不同价态的金属离子Ag+,Ni2+,Ce3+交换到铝化的大孔径SBA-15介孔材料(SBA-15-L)上,制备了吸附剂Ag/Al-SBA-15-L,Ni/Al-SBA-15-L,Ce/Al-SBA-15-L。脱硫实验表明,所制备的吸附剂可将硫含量为0.015(wt)%的模拟航空煤油,脱硫至硫含量低于0.0001(wt)%,并且Ag/Al-SBA-15-L的吸附脱硫能力强于Ni/Al-SBA-15-L和Ce/Al-SBA-15。通过ICP-AES分析表明,在铝化的大孔SBA-15上,Ag+的交换量分别是Ni2+和Ce3+的13和65倍。达到吸附饱和时,每个活性中心离子Ag+、Ni2+、Ce3+上可分别吸附0.027,0.570,0.752个硫原子,即金属离子固有的吸附脱硫能力为Ce3+>Ni2+>Ag+。     

负载型Fe_2O_3对乙苯脱氢反应的催化性能

以正硅酸乙酯(TEOS)为硅源,分别以十六烷基三甲基溴化铵(CTAB)和P123为模板剂通过溶胶凝胶法、水热合成法合成出MCM-41、Al-MCM-41、SBA-15介孔分子筛,然后将其作为催化剂载体负载Fe2O3,应用到乙苯催化脱氢制苯乙烯的反应中,考察了不同负载量对乙苯脱氢反应性能的影响,探讨了催化剂的活性保持时间。结果表明,将介孔分子筛作为催化剂载体负载Fe2O3应用到乙苯脱氢反应,当负载量为60%时乙苯的转化率和苯乙烯的选择性均最高。当n Si/n Al为60时,Fe2O3/Al-MCM-41催化性能最好。Fe2O3/SBA-15所持续的活性时间最长。     

金属离子对二(2-乙基己基)磷酸钠微乳体系相行为的影响

对于由二(2-乙基己基)磷酸钠(NaDEHP)、正辛烷和金属盐水溶液组成的微乳体系,研究了金属离子(Na+、Ca2+、Mn2+、Fe3+、Co2+、Ni2+、Cu2+、Zn2+、Al3+)对相行为的影响。随金属盐水溶液浓度增加,体系发生WinsorI→Ⅲ→Ⅱ型转变。含不同金属盐的体系产生中相微乳液的金属盐浓度范围(中相盐宽)是不同的。所研究的金属离子按中相盐宽增加排出的顺序是:Fe3+相似文献   

Al-MCM-41分子筛对多环烃的催化异构化性能

采用室温法合成了Al-MCM-41分子筛,采用XRD、FT-IR和表面测定仪等方法表征了Al-MCM-41分子筛的结构。以多环烃endo-TCD（桥式四氢双环戊二烯）异构化反应为例考察了不同铝硅物质的量比的Al-MCM-41分子筛催化异构化性能,在此基础上研究了表面负载无机酸及贵金属Pt的促进作用。结果表明,Al-MCM-41分子筛对endo-TCD具有良好的催化异构化作用,无机酸的负载对催化剂活性和提高金刚烷收率具有一定促进作用,而采用化学还原法负载Pt则未达到预期目的。     

Ni2P/Al-MCM-41催化剂的制备及其加氢脱硫性能

以硅酸钠为硅源、硫酸铝为铝源、十六烷基三甲基溴化铵（CTAB）作模板剂,采用共沸蒸馏与超声波分散技术相结合的方法制备了介孔分子筛Al-MCM-41。以Al-MCM-41为载体、硝酸镍和磷酸氢二氨为原料,采用超声波振荡、程序升温还原法制备了Ni₂P/Al-MCM-41催化剂,并对Al-MCM-41和Ni₂P/Al-MCM-41进行了傅里叶变换红外光谱、比表面积测定、X射线衍射、扫描电镜表征。考察了Ni₂P/Al-MCM-41催化剂对噻吩加氢脱硫的催化性能。结果表明：采用超声波制得的Al-MCM-41其比表面积、孔容和孔径明显高于常规搅拌制得的Al-MCM-41,共沸蒸馏制得的Al-MCM-41其比表面积、孔容和孔径高于未共沸蒸馏的Al-MCM-41;在反应时间为5 h、548 K、3.5 MPa条件下,Ni₂P/Al-MCM-41催化剂对噻吩加氢脱硫的转化率接近100%。     

ZSM-5/SBA-15催化氧化脱硫催化剂的制备表征及脱硫性能研究

结合分子筛ZSM-5与SBA-15自身的优点,合成了不同质量比例的ZSM-5/SBA-15微孔-介孔复合分子筛,并进行XRD、N2吸附-脱附表征,分析其结构特征。以其为载体负载金属W、Ni、Ce、Cu,制备出不同的氧化脱硫催化剂,对模拟油进行氧化脱硫研究。结果表明,负载金属W制备出的WO3-ZSM-5/SBA-15(ZSM-5质量分数为10%)复合分子筛,脱硫效果最好,脱硫率为75.44%。     

ZSM-5/SBA-15催化氧化脱硫催化剂的制备表征及脱硫性能研究

结合分子筛ZSM-5与SBA-15自身的优点,合成了不同质量比例的ZSM-5/SBA-15微孔-介孔复合分子筛,并进行XRD、N2吸附-脱附表征,分析其结构特征。以其为载体负载金属W、Ni、Ce、Cu,制备出不同的氧化脱硫催化剂,对模拟油进行氧化脱硫研究。结果表明,负载金属W制备出的WO3-ZSM-5/SBA-15(ZSM-5质量分数为10%)复合分子筛,脱硫效果最好,脱硫率为75.44%。     

胺基稻草纤维的制备及对电镀废水中Fe3+、Ni2+、Cu2+、Zn2+的吸附

以稻草秸秆为原料,用多种胺基试剂经氯化和胺化反应对稻草秸秆进行改性,制成多种改性胺基稻草纤维并用于电镀废水中重金属离子Fe3+、Ni2+、Cu2+、Zn2+的吸附,并用扫描电子显微镜、X射线衍射仪等分析手段对改性纤维的表面形貌和结构性能进行了表征。实验结果表明:乙二胺基稻草纤维吸附Fe3+、Ni2+、Cu2+、Zn2+性能明显优于稻草纤维原料和其他胺基改性稻草纤维;胺基改性稻草纤维对金属离子吸附能力与含氮量有一定相关性;乙二胺基稻草纤维吸附电镀废液中Fe、Ni、Cu、Zn效果明显。     

改性MCM-22分子筛吸附脱除油品中二氯甲烷的研究

采用离子交换法制备了不同金属离子(Ni2+、Co2+、Fe3+)改性的MCM-22分子筛。采用XRD、NH3-TPD和BET对吸附剂进行了表征,同时,考察了MCM-22分子筛经不同金属离子改性后作为吸附剂对模型化合物的脱氯性能,优化了吸附剂的活化条件,并在吸附试验中研究了最优吸附剂吸附二氯甲烷的动力学和吸附活化能。结果表明,吸附剂的最优活化温度及时间分别为450℃和4 h。脱氯效果顺序为:Ni MCM-22Co MCM-22Fe MCM-22MCM-22,最优吸附剂Ni MCM-22分子筛上吸附动力学可用拟二级动力学进行较好的描述,吸附过程以化学吸附为主。     

Al-MCM-41介孔分子筛吸附喹啉的性能

在碱性条件下,采用水热晶化法,以偏硅酸钠为硅源,铝酸钠为铝源,CTAB为结构模板剂,成功合成出了含铝介孔分子筛Al-MCM-41。采用XRD、BET等手段对合成的Al-MCM-41进行表征,对柴油中的氮化物喹啉进行了吸附实验,考察了Al-MCM-41介孔分子筛对氮化物喹啉的吸附能力,探究了硅铝比为60的Al-MCM-41分子筛对喹啉溶液吸附的热力学和动力学行为,测得353.15～393.15 K 温度范围内的吸附等温线数据,用Langmuir、Freundlich方程对此进行拟合,并根据热力学原理计算得到吸附过程中的ΔH、ΔG、ΔS值和吸附表观活化能。结果表明, 硅铝比为60的Al-MCM-41具有较大的孔容、比表面积和较窄的孔径分布,结晶度和有序性高。等温吸附平衡符合Freundlich 等温线模型,其ΔH -0.7682 kJ·mol^-1,ΔG -28.1215 kJ·mol^-1, ΔS 73.2434 J·mol^-1·K^-1,吸附动力学符合Pseudo拟二级方程,E_a为2.8575 kJ·mol^-1。     

The synthesis of Al-MCM-41 from volclay — A low-cost Al and Si source

The alkaline fusion of volclay (a low-cost sodium exchanged smectite) was used as source to generate the Si and Al components which were effectively transformed into mesoporous Al-MCM-41 depending on hydrothermal condition. The Al-MCM-41 materials were investigated by powder X-ray diffraction (XRD), N₂ adsorption–desorption measurements and both scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM). The volclay which converted into a silicon and an aluminium source allowed the formation of well ordered mesoporous Al-MCM-41 materials with high aluminium content (roughly 4 times higher than a Al-MCM-41 produced by a standard method), a high specific surface area (1060 m²/g), a pore volume of 0.8 cm³/g (for pore width < 7.1 nm) with an mono-modal pore distribution with a maximum in the mesoporous pore size of 3.8 nm in pore width.     

Uptake of decontaminating agent from aqueous solution: a study on adsorption behaviour of oxalic acid over Al-MCM-41 adsorbents

Hydrothermal method was followed to synthesis the mesoporous Al-MCM-41 (Si/Al = 25, 50, 75 and 100) and Si-MCM-41 molecular sieves using a cetyltrimethylammonium bromide as a surfactant and the materials were unambiguously characterized by XRD, N₂ sorption studies, ²⁷Al MAS-NMR and TEM. The removal of oxalic acid from aqueous solution was studied through an adsorption process because oxalic acid may cause complexes with radioactive cations during decontamination operation in nuclear industry, which resulting in interferences in their removal by conventional treatment. Adsorption of oxalic acid over Al-MCM-41 shows the applicability of Langmuir isotherm and follows first order kinetics. The effects of parameters such as contact time, concentration of oxalic acid, adsorbents (various Si/Al ratios of Al-MCM-41, Si-MCM-41 and activated charcoal) and pH have been investigated to yield higher removal of oxalic acid. The percentage of oxalic acid adsorbed per unit gram of adsorbent for Al-MCM-41 at Si/Al = 100, 75, 50 and 25, Si-MCM-41, and activated charcoal are 34.6, 40.9, 51.4, 61.3, 16.1 and 60, respectively. Retainment of crystallinity and absence of structural collapse of Al-MCM-41 after desorption and adsorption of oxalic acid, respectively has been achieved in this study.     

Synthesis and Characterization of Al-MCM-41 and Al-MCM-48 Mesoporous Materials

A novel route in the synthesis of Al-MCM-41 and Al-MCM-48, using tetraethoxysilane (TEOS) and sodium aluminate (NaAlO₂) as Si and Al source has been obtained. The effect of surfactant nature and the synthesis conditions such as surfactant/Si ratio and hydrothermal treatment time on the formed mesostructure regularity has been studied. Different methods of template removal have also been evaluated. The samples were characterized by X-ray diffraction, nitrogen physisorption, FT-IR, and solid-state MAS NMR spectroscopy.     

航空煤油在不同孔径的Ag基介孔材料吸附剂上深度吸附脱硫的研究

以3种不同孔径的介孔材料MCM-41,SBA-15,大孔SBA-15(SBA-15-L)为载体,采用离子交换法制备了Ag/Al-MCM-41,Ag/Al-SBA-15和Ag/Al-SBA-15-L介孔材料吸附剂。利用XRD,N2吸附,SEM-EDS,ICP-MS等手段对所制备的吸附剂进行了表征,并在固定床上对航空煤油进行了吸附脱硫研究。结果表明,交换Ag+所制备的吸附剂依然保持介孔材料的特性,并可将含S量为150×10-6的航空煤油中的硫化物,选择性的吸附脱除到S含量低于1.0×10-6。其中,在Ag/Al-MCM-41,Ag/Al-SBA-15和Ag/Al-SBA-15-L吸附剂上,可分别得到8.0,9.0和17.0mL的清洁航空煤油(含硫量小于1.0×10-6)。实验结果也表明,所制备的吸附剂吸附脱硫性能主要取决于介孔材料载体的孔径大小,载体的孔径越大,Ag+的利用率越高,吸附剂的吸附脱硫性能越强。将吸附饱和的Ag/Al-SBA-15-L吸附剂,于空气中在350℃进行再生5h,吸附剂的吸附性能可以100%的恢复。     

煤系高岭土合成Al-MCM-41及镧改性后有效脱除磷

用煤系高岭土作为硅源和铝源合成介孔分子筛Al-MCM-41,然后浸渍镧获得一种具有高吸附容量和磷去除率的新型磷酸根吸附剂。分别考察了载体和镧负载量对吸附磷酸根性能影响。 硅铝比为48的介孔分子筛Al₄₈-MCM-41具有非常规整的一维孔道结构,作为载体为负载镧氧化物提供一个好的空间结构。负载量为15%的 La₁₅-Al₄₈-MCM-41磷酸根吸附量吸附时间先呈线性增长,后缓慢增加,最后趋于平衡,饱和吸附量为60.43 mg/g,投加量为0.12 g时磷去除率96.01%。通过比较不同初始pH值条件下吸附过程中的pH值变化情况,发现吸附剂表面上的羟基和磷酸根之间的离子交换是去除磷酸盐的主要原因。     

Effect of lanthanum addition on the thiophene hydrodesulfurization activity over Al-MCM-41 supported molybdenum catalysts

A series of Al-MCM-41 modified with 1–7% lanthanum were used as supports to prepare the Mo/La–Al-MCM-41 catalysts containing 10 wt.% molybdenum. The supports and catalysts were characterized with XRD, BET, XPS, TPD, TEM and SEM, and their catalytic activities were tested for thiophene hydrodesulfurization. The La addition did not cause any significant collapse of the structure and morphology of Al-MCM-41 samples, and increased the acidity of Al-MCM-41 samples. The Mo/La–Al-MCM-41 catalysts showed higher thiophene HDS activity than non-modified catalysts. The La-modified catalysts showed an enhanced butene selectivity but a decreased tetrahydrothiophene selectivity, indicating that the La–Al-MCM-41 supports contained a larger amount of acid sites.     

Evaluation of various types of Al-MCM-41 materials as catalysts in biomass pyrolysis for the production of bio-fuels and chemicals

MCM-41, is one of the latest members of the mesoporous family of materials. They possess a hexagonal array of uniform mesopores (1.4–10 nm), high surface areas (>1000 m²/g) and moderate acidity. Due to these properties the MCM-41 materials are currently under study in a variety of processes as catalysts or catalyst supports. The objective of this study was to evaluate different types of MCM-41 materials as potential catalysts in the catalytic biomass pyrolysis process. We expected that the very high pore size and the mild acidity of these materials could be beneficial to reformulate the high molecular weight primary molecules from biomass pyrolysis producing useful chemical (and especially phenolic compounds) and lighter bio-oil with less heavy molecules. Three different samples of Al-MCM-41 materials (with different Si/Al ratio) and three metal containing mesoporous samples (Cu–Al-MCM-41, Fe–Al-MCM-41 and Zn–Al-MCM-41) have been synthesised, characterized and tested as catalysts in the biomass catalytic pyrolysis process using a fixed bed pyrolysis combined with a fixed catalytic reactor and two different types of biomass feeds. Compared to conventional (non-catalytic) pyrolysis, it was found that the presence of the MCM-41 material alters significantly the quality of the pyrolysis products. All catalysts were found to increase the amount of phenolic compounds, which are very important in the chemical (adhesives) industry. A low Si/Al ratio was found to have a positive effect on product yields and composition. Fe–Al-MCM-41 and Cu–Al-MCM-41 are the best metal-containing catalysts in terms of phenols production. The presence of the Al-MCM-41 material was also found to decrease the fraction of undesirable oxygenated compounds in the bio-oil produced, which is an indication that the bio-oil produced is more stable.     

砷在杂原子介孔分子筛上的吸附行为研究

介孔分子筛具有大比表面积、长程有序结构和可调孔径等优点,经过杂原子掺杂后具有优异的吸附除砷能力。在十六烷基三甲基溴化铵、正硅酸乙酯、氢氧化钠体系中,添加不同铝源、铁源制备了杂原子MCM-41介孔分子筛。XRD衍射分析表明合成产物具有规整的介孔孔道结构。砷吸附实验结构表明,在碱性条件下,Al-MCM-41对砷的吸附性能最佳。在酸性条件下,Fe-MCM-41对砷的吸附性能最佳。而且在酸性条件下Fe-MCM-41分子筛对砷的吸附明显优于Al-MCM-41。中性再生条件下,Fe-MCM-41分子筛对砷的去除率达到95%。这说明液相中砷酸根和Fe-MCM-41分子筛生成了砷酸铁表面沉淀,从而使液相中残留砷浓度降到较低的水平。