MEA、DEA浸渍改性SBA-15对CO_2吸附性能的研究

为实现CO_2的高效捕集,采用浸渍法将MEA、DEA分别负载到介孔材料SBA-15的孔道内,研究改性前后样品对CO_2吸附性能的影响,其中主要分析不同温度下CO_2吸附量的变化情况。通过X射线衍射(XRD)、低温N2吸附-脱附(BET)、热重分析(TGA)等手段对所得样品进行表征。结果表明,MEA、DEA均负载到SBA-15的孔道内部,且没有破坏介孔结构;经MEA、DEA改性后样品的吸附性能显著提高,最大吸附量分别提高了51%和75%。     

蠕虫型介孔SiO_2的改性及对CO_2吸附性能的研究

有机胺为氨基改性剂,采用浸渍的方法对蠕虫型介孔SiO2(MSU-J)改性。利用FT-IR,N2吸附/脱附,元素分析,TG及TEM进行表征。测定对CO2的吸附性能,结果表明,有机胺修饰前后MSU-J的介孔结构没有发生变化,孔径,孔容及比表面积有所降低。改性前后MSU-J对CO2的吸附性能发生显著变化,由物理吸附转化为以氨基为活性中心的化学吸附,且吸附温度,氨基的含量对吸附量均有影响。稳定性实验表明,有机胺改性MSU-J材料重复使用6次,对CO2吸附量无明显下降。     

钙镁改性有序介孔氧化铝对电厂尾气CO_2吸附性能的研究

以聚乙二醇1540为模板剂,Al(NO3)3为铝源,(NH3)2CO3为沉淀剂,Ca(NO3)2和Mg(NO3)2分别作为改性剂,采用沉淀法一步合成钙镁改性的有序介孔氧化铝(OMA-Ca、OMA-Mg)。通过XRD、TEM、氮等温吸脱附等测试技术对其进行表征,同时考察改性前后有序介孔氧化铝对电厂尾气CO2的吸附性能。结果表明,当Ca2+、Mg2+的负载量为10%、吸附温度为65℃、吸附气体体积流量为35mL/min时对CO2的吸附量最大,分别为9.36mg/g和10.45mg/g,经5次循环脱-吸附实验后其结构性质和吸附性能仍保持稳定,再生性能良好。     

有序介孔炭合成、改性及其对汞离子的吸附性能

以有序介孔硅基材料(SBA-15)为模板,内烯酸低聚物为前驱物合成有序介孔结构的炭材料(OMC),并以化学方法将含氮基官能闭嫁接在有序介孔炭的表面.利用扫描电子显微镜(SEM),透射电子显微镜(TEM),红外光谱(FT-IR),X射线衍射(XRD)和氮气吸附-脱附(BET)对介孔炭进行表征.结果表明:表面改性后有序介孔炭的结构发生一定变化,但孔道特征仍保持二维六方有序性.合成的有序介孔炭及经乙二胺表而改性后胺化有序介孔炭的比表而积、平均介孔直径、平均孔容积分别为607 m2/g,4.1 nm,0.62 cm3/g和558 m2/g,3.8 nm,0.58cm3/g.对有序介孔炭及改性有序介孔炭进行的汞吸附实验,发现表面改性前后有序介孔炭对Hg(II)的吸附性能发生显著变化.嫁接胺基功能团后,其吸附容量增加一倍,表明胺基改性的OMC对汞有亲和作用.     

新型SiO_2基微/介孔材料的合成及其对集成电路生产中VOCs废气的吸附研究

采用新型SiO2基微/介孔材料为吸附剂,针对集成电路(Integrated Ciruit,IC)产业中废气排放的特点,以丙酮、苯、甲苯为挥发性有机化合物(VOCs)的典型,进行了一系列吸附实验.用气相色谱定时测取VOCs获得动态穿透曲线,就各VOCs分别在SiO2基微/介孔材料、疏水沸石、活性炭3种吸附荆上的吸附以及SiO2基微/介孔材料对3种不同VOCs的吸附进行了研究,同时考察了水蒸汽脱附对该材料吸附性能的影响.实验结果显示,该吸附剂在对VOCs的吸附中较疏水沸石FX-I和活性炭有着明显的优势,主要表现在透过时间的延迟和传质区长度的缩短.     

介孔碳负载铂催化剂的制备及降解甲醛的研究

以嵌段共聚物F127为软模板,低分子量酚醛树脂为前驱体,通过溶剂挥发诱导自组装(EISA)方法制得介孔碳(OMC),经浸渍还原法制备介孔碳负载铂催化剂(Pt/OMC)。采用场发射扫描电镜(FESEM)、X射线能谱(EDS)、透射电镜(TEM)、X射线衍射(XRD)、N2吸附-脱附等温线等对其进行了表征。Pt/OMC对甲醛的催化性能结果表明,反应7h甲醛的去除率可达92.5%,甲醛可矿化为CO2。还研究了甲醛的降解机理,甲醛首先被氧化成甲酸,然后再矿化为CO2和H2O。     

Ce改性介孔γ-Al2O3的一步水热合成及其对噻吩的吸附性能

采用一步水热合成法,以硝酸铝为铝源,P123为模板剂,NaOH、Na2CO3和K2CO3分别为沉淀剂,硝酸铈为铈源,制备出负载Ce的金属有序介孔γ-Al2O3,并采用低温N2吸附-脱附和XRD等方法对其结构进行表征,同时验证了Ce改性的介孔γ-Al2 O3对模型燃油中的噻吩的吸附性能.结果表明:这3种沉淀剂都能制备出比...     

介孔材料CO2吸附性能的研究进展

介孔材料以其适中的孔径、大的比表面积、较高的热稳定性和水热稳定性,在吸附、催化、分离等方面有着广阔的应用前景。综述了近年来介孔材料在CO2吸附领域的研究进展,重点介绍了介孔材料及改性介孔材料吸收CO2的方法;并指出以新材料特别是介孔材料为主体进行碳捕集是今后的主要研究方向。     

镧、铈改性介孔氧化铝对氟离子的吸附

以La、Ce为改性物负载至其他载体表面作为高效除氟吸附剂已经受到广泛的关注。但是将La和Ce负载到介孔氧化铝(MA)却少见报道。本研究制备了La和Ce改性介孔氧化铝并将其用于氟的去除。采用N2吸脱附等温线、X射线衍射(XRD)、傅里叶红外光谱(FTIR)对该吸附剂的结构性质进行了表征。同时,考察了吸附剂接触时间、初始浓度和溶液pH等吸附条件对氟离子吸附效果的影响。结果表明,反应在150 min时达到吸附平衡,此时La/MA的氟去除率达92. 2%,吸附氟容量大小为La/MA Ce/MA MA;氟吸附量随初始浓度的增大而增大;在pH值为5～9时,除氟效果较好;吸附等温线方程均符合Langmuir等温吸附模型; La/MA的氟离子最大吸附容量为27. 9 mg/g;共存阴离子对氟吸附的影响程度为CO32- SO42- NO3- Cl-。最后比较了吸附前后的FTIR,可以看出La/MA对氟离子去除效果最佳。     

介孔碳负载铂催化剂的制备及降解甲醛的研究

以嵌段共聚物F127为软模板,低分子量酚醛树脂为前驱体,通过溶剂挥发诱导自组装(EISA)方法制得介孔碳(OMC),经浸渍还原法制备介孔碳负载铂 催 化 剂(Pt/OMC)。采 用 场 发 射 扫 描 电 镜(FESEM)、X射线能谱(EDS)、透射电镜(TEM)、X射线衍射(XRD)、N2吸附-脱附等温线等对其进行了表征。Pt/OMC对甲醛的催化性能结果表明,反应7h甲醛的去除率可达92.5%,甲醛可矿化为CO2。还研究了甲醛的降解机理,甲醛首先被氧化成甲酸,然后再矿化为CO2和H2O。     

混合超微孔材料中CO2/N2吸附与分离的理论研究

碳捕获与封存技术是一种具有前景的CO₂减排策略。本工作采用巨正则蒙特卡洛模拟研究了温度为298 K、压强在0~5 kPa范围内三种混合超微孔材料SIFSIX-X-Cu(以SiF₆ ^2-排列, Cu为金属中心, X=2, 3, O)中CO₂/N₂吸附与分离的行为。结果显示, 相比于SIFSIX-2-Cu, SIFSIX-3-Cu和SIFSIX-O-Cu中CO₂在0.5 kPa就达到吸附饱和, 且在1 kPa下的吸附量分别达到了2.70与2.39 mmol·g ^-1。CO₂/N₂混合气体中CO₂的吸附量几乎没有下降。SIFSIX-3-Cu和SIFSIX-O-Cu具有接近于CO₂分子动力学直径的孔径, 对CO₂亲和力较大, 吸附热分别达到了59和66 kJ·mol ^-1。密度泛函理论分析发现, 在两种结构中每个孔隙只吸附一个CO₂分子, 且几乎处于孔道的中心。本工作为低压下吸附与分离CO₂的混合超微孔材料的开发提供了理论指导。     

不同沉淀剂对所制备的LiNi0.8Co0.1Mn0.1O2正极材料性能影响的研究

采用共沉淀-高温固相烧结法,控制合成条件,以不同的沉淀剂(Na2CO3、NaOH)制备出正极材料。通过XRD、SEM及电池测试系统对不同沉淀剂制备的正极材料进行结构、形貌和电化学性能的表征,对比两者存在的优缺点。研究结果表明,以NaOH为沉淀剂制备的正极材料有更好的层状结构,形貌也更好,充放电性能和倍率性能也较好。其首次放电比容量达到了187.9mAh/g,最高可达196.2mAh/g,50次充放电循环后,容量保持率为81.6%;以Na2CO3为沉淀剂制备的正极材料的放电比容量较低,但容量保持率较高,为85.3%。     

Carbon dioxide adsorption using amine-functionalized mesocellular siliceous foams

Mesocellular siliceous foams (MCFs) with and without remaining template were prepared and modified by polyethylenimine (PEI) or mixed amines [Diethylenetriamine and PEI or 3-aminopropyltrimethoxysilane (APTMS) and PEI]. These samples were evaluated for their adsorption capacities for CO₂ at different temperatures. With the increase of PEI loading, the optimal adsorption temperature shifts to higher temperature for samples prepared in our study. The remaining template in MCF materials plays an important role in promoting CO₂ adsorption capacity, which could be 3.24 mmol/g when the amount of PEI loading is 70 % at 85 °C. Meanwhile, the remaining template contributes greatly to the dispersion of PEI, resulting in higher adsorption capacity at low temperature. The effect of the amount of remaining template was studied, and it was found that CO₂ adsorption capacity decreases with increasing template. The CO₂ adsorption capacities for mixed-amine-modified MCFs are higher than those of the samples modified by PEI only, which was ascribed to the better dispersion of PEI. MCF modified with the mixing of APTMS and PEI exhibited highest adsorption capacity of 2.67 mmol/g at 50 °C. These findings reveal that pore structure, PEI loading, PEI dispersion, and remaining template work together to influence the CO₂ adsorption performance.     

Gravimetric analysis of CO2 adsorption on activated carbon at various pressures and temperatures using piezoelectric microcantilevers

We investigated the adsorption and desorption of CO(2) on activated carbon using piezoelectric microcantilevers. After coating the free end of a cantilever with activated carbon, variations in the resonance frequency of the cantilever were measured as a function of CO(2) pressure, which is related to mass changes due to the adsorption or desorption of CO(2). The pressure-dependent viscous damping effects were compensated in the calculation of the CO(2) adsorption capacity of the activated carbon by comparing the frequency differences between the coated and uncoated cantilevers. The mass sensitivity of the piezoelectric cantilever was found to be better than 1 pg. The fractional coverage of CO(2) agreed with a Langmuir adsorption isotherm, indicating that a submonolayer of adsorbed CO(2) occurred on the surface of the activated carbon under the experimental conditions. The heat of adsorption was determined using the Clausius-Clapeyron relation and the fractional coverage of CO(2) at various temperatures and pressures.     

基于短孔道Zr-Ce-SBA-15固定胃蛋白酶的活性生物催化剂

在不外加无机酸的条件下, 通过水热合成法制备了短孔道六方板状有序介孔材料Zr-Ce-SBA-15 (ZCS). 以ZCS和传统SBA-15为载体对胃蛋白酶进行固定, 并利用N-(2-氨乙基)-3-氨丙基三甲氧基硅烷(AAPTS)对酶固定化材料进行功能化, 以缩小开口孔径从而减少酶泄漏. 采用小角X射线衍射、扫描电镜、透射电镜、氮气吸附和红外光谱对样品进行结构表征. 结果表明, 胃蛋白酶成功固定到介孔孔道中, AAPTS嫁接到材料中且没有破坏介孔结构. 固定化实验表明相比于SBA-15, ZCS对胃蛋白酶具有较快的吸附速度和较强的固定化能力(最大负载量为257.9 mg/g), 短孔道材料能有效地促进分子的扩散传递. 催化活性测定以牛血红蛋白为探针物, 与游离酶相比, 固定酶对牛血红蛋白保持着稳定的活性.     

氨基功能化硅胶的制备及其对CO_2的吸附性能

以乙醇胺(MEA)、二乙醇胺(DEA)、二乙烯三胺(DETA)和四乙烯五胺(TEPA)物理浸渍后的白色玻璃状无定型硅胶(Q)作为CO_2吸附剂,考察了有机胺负载量、有机胺分子链长短和羟基数量对CO_2吸附性能的影响以及吸附剂的再生性能。实验结果表明:50%TEPA-Q具有最大的CO_2吸附量,为2.589mmol/g。经过10次吸附-真空脱附循环后,50%TEPA-Q的CO_2吸附能力仅下降了8.034%,具有较好的循环稳定性。     

用于CO2捕获的智能吸附剂:促使强吸附活性位响应于可见光

基于光响应吸附剂的吸附过程可控性好、能源效率高,其在CO2捕获中的应用受到关注.然而,大多数报道的光响应吸附剂是基于弱吸附位点设计的,通过其结构或位阻的变化控制CO2吸附.此外,还需要用到紫外光来调节吸附能力.本文首次报道了用于CO2捕获的智能吸附剂,促使强吸附活性位响应于可见光.吸附剂的制备通过将伯胺和分散红(DR1...     

A partially interpenetrated metal-organic framework for selective hysteretic sorption of carbon dioxide

The selective capture of carbon dioxide in porous materials has potential for the storage and purification of fuel and flue gases. However, adsorption capacities under dynamic conditions are often insufficient for practical applications, and strategies to enhance CO(2)-host selectivity are required. The unique partially interpenetrated metal-organic framework NOTT-202 represents a new class of dynamic material that undergoes pronounced framework phase transition on desolvation. We report temperature-dependent adsorption/desorption hysteresis in desolvated NOTT-202a that responds selectively to CO(2). The CO(2) isotherm shows three steps in the adsorption profile at 195?K, and stepwise filling of pores generated within the observed partially interpenetrated structure has been modelled by grand canonical Monte Carlo simulations. Adsorption of N(2), CH(4), O(2), Ar and H(2) exhibits reversible isotherms without hysteresis under the same conditions, and this allows capture of gases at high pressure, but selectively leaves CO(2) trapped in the nanopores at low pressure.     

沥青基球形活性炭对CO2的吸脱附行为研究

考察了沥青基球形活性炭(PSAC)的孔结构与CO2吸附容量间的内在关系及其脱附性能.采用N2吸附法分析PSAC的孔结构,由穿透曲线测试其对CO2的平衡吸附量.实验结果表明:在CO2/N2混合气氛下,活性炭对CO2的吸附容量与孔径小于1nm的微孔比表面积呈线性关系;当PSAC担载5%的三聚氰胺后,对CO2(15%)的平衡吸附量由0.91mmol/g增加到1.15mmol/g,提高了26.3%;采用抽真空脱附时,循环脱附效率为74.6%,而电解吸-抽真空耦合脱附工艺可使CO2的循环脱附效率接近100%.     

Highly basic CaO nanoparticles in mesoporous carbon materials and their excellent catalytic activity

Highly basic CaO nanoparticles immobilized mesoporous carbon materials (CaO-CMK-3) with different pore diameters have been successfully prepared by using wet-impregnation method. The prepared materials were subjected to extensive characterization studies using sophisticated techniques such as XRD, nitrogen adsorption, HRSEM-EDX, HRTEM and temperature programmed desorption of CO2 (TPD of CO2). The physico-chemical characterization results revealed that these materials possess highly dispersed CaO nanoparticles, excellent nanopores with well-ordered structure, high specific surface area, large specific pore volume, pore diameter and very high basicity. We have also demonstrated that the basicity of the CaO-CMK-3 samples can be controlled by simply varying the amount of CaO loading and pore diameter of the carbon support. The basic catalytic performance of the samples was investigated in the base-catalyzed transesterification of ethylacetoacetate by aryl, aliphatic and cyclic primary alcohols. CMK-3 catalyst with higher CaO loading and larger pore diameter was found to be highly active with higher conversion within a very short reaction time. The activity of 30% CaO-CMK3-150 catalyst for transesterification of ethylacetoacetate using different alcohols increases in the following order: octanol > butanol > cyclohexanol > benzyl alcohol > furfuryl alcohol.