分子筛SBA-15负载离子液体[P_(66614)][Triz]脱除氢烷气中CO_2

以高效吸收CO_2的离子液体(IL)[P_(66614)][Triz]作为吸收剂,通过浸渍法负载到两种不同孔径的介孔分子筛SBA-15上,用于脱除生物氢烷气中CO_2,并利用N2吸附仪、扫描电子显微镜(SEM)和高倍透射电子显微镜(HRTEM)对负载材料进行了表征分析。混合吸收剂SBA-15(4.3 nm)-50%[Triz]的吸收容量和吸收速率比SBA-15(6.6 nm)-50%[Triz]的分别提高了12.4%和95.1%,这是由于SBA-15(4.3 nm)的孔道长度更短,避免了填充在孔道内的[P_(66614)][Triz]在反应过程中接触不到CO_2,从而比SBA-15(6.6 nm)-50%[Triz]有更多IL反应活性点参与反应。还研究了不同氢烷气速率下SBA-15(4.3 nm)-50%[Triz]对CO_2的吸收并与2种吸附动力学模型相拟合,结果表明SBA-15(4.3nm)-50%[Triz]对CO_2的吸收更符合准二级吸附动力学模型,表明吸附过程受化学吸附机理的控制,验证了[P_(66614)][Triz]是通过化学反应脱除CO_2。     

无水氨基酸类离子液体-聚乙二醇混合溶剂吸收CO2的动力学

以聚乙二醇400（PEG400）为溶剂,氨基酸类离子液体（AAILs）作为化学吸收剂的混合体系具有蒸汽压极低、热稳定性好、黏度和再生能耗低、CO₂吸收量和选择性高等优点,适用于燃烧前CO₂捕集过程的高温高压吸收条件。本文采用压降法,测定了以四正丁基膦（[P₄₄₄₄]⁺）为阳离子,甘氨酸（Gly）、丙氨酸（Ala）和脯氨酸（Pro）作为阴离子的3种氨基酸类离子液体的混合溶剂体系对CO₂的吸收速率,并建立了该无水体系的CO₂吸收动力学模型。对于反应速率而言,在333.15K时,[P₄₄₄₄][Gly]-PEG400 > [P₄₄₄₄][Pro]-PEG400 > [P₄₄₄₄][Ala]-PEG400,温度升高至373.15K时,[P₄₄₄₄][Pro]-PEG400 > [P4444][Gly]-PEG400 > [P₄₄₄₄][Ala]-PEG400;根据相关吸收动力学参数,推测出CO₂在AAILs-PEG400中的反应均为快反应。通过研究其吸收动力学,获得了关键的吸收动力学数据,为后续的工业开发设计提供基础数据和设计依据。     

负载[APMIm][Br]离子液体吸收CO2的性能

1-氨丙基-3-甲基咪唑溴盐（[APMIm][Br]）离子液体通过化学反应捕集CO₂。采用浸渍-蒸发将[APMIm][Br]离子液体负载在硅胶表面,通过比表面孔隙吸附测定仪、热重分析仪（TGA）对吸收剂的结构与性能进行研究,负载量为10%～50%,温度为303.15～323.15 K,CO₂浓度分别为10%、30%、50%。结果表明：硅胶表面的离子液体薄膜厚度达到86 nm（负载40%）时,具有最快的吸收速率,且受CO₂浓度和温度变化的影响较小,平衡吸收量在50% CO₂体系中达到理论吸收量的80%,随着温度的升高而降低,当负载量为50%时,膜厚增加到230 nm,导致吸收速率和平衡吸收量大幅度下降。值得注意的是：负载离子液体吸收剂在循环使用3次之后,结构与性能均保持不变,表现出一定的工业运用前景。     

混合胺改性SBA-15的二氧化碳吸附特性

为实现廉价高效的二氧化碳捕集，新型燃烧后CO₂捕集固体吸附材料的设计和开发具有重要的研究意义。为提高CO₂吸附量，胺功能化改性吸附剂的方法主要有湿浸渍和表面嫁接。基于此，提出了“混合胺”修饰的概念，把湿浸渍和表面嫁接两种改性技术结合起来。把3-氨丙基三甲氧基硅烷（APTS）嫁接到分子筛SBA-15孔道表面，再把聚乙烯亚胺（PEI）浸渍到载体孔道的间隙，制备出高密度胺功能化的CO₂吸附剂。主要考察了不同含量的PEI和APTS功能化SBA-15的结构性能、CO₂吸附量及胺吸附效率。CO₂吸附结果表明，混合胺功能化SBA-15吸附主要依赖于动力学扩散。其中，SBA-15-（APTS-0.5-PEI-50），SBA-15-（APTS-1.0-PEI-50）和SBA-15-（APTS-2.0-PEI-30）在75℃时具有很好的吸附潜力。混合胺功能化SBA-15的胺吸附效率介于单纯嫁接和单纯浸渍的胺功能化SBA-15之间。     

[Bmim][BF4]/MEA混合水溶液吸收CO2的吸收性能与液液分相机理

对液液两相CO₂吸收剂1-丁基-3-甲基咪唑四氟硼酸盐（[Bmim][BF₄]）/乙醇胺（MEA）混合水溶液吸收性能进行了实验测定,研究了离子液体[Bmim][BF₄]的引入对吸收性能和液液分相的影响,并通过定量碳谱核磁共振法对分相机理和各相中的物质分布进行分析。研究结果表明,一定配比的[Bmim][BF₄]/MEA混合水溶液吸收CO₂之后会出现互不相溶的液液两相,这种现象伴随着CO₂产物的富集;导致液液分相的原因是氨基甲酸盐浓度的增大;随着[Bmim][BF₄]质量分数的增大,溶液吸收速率呈现出先增大后减小的趋势;分层后H₂O主要分布在富液相,[Bmim][BF₄]主要分布在贫液相,H₂O的质量分数直接影响分层后富液相的传质性能。     

[Bmim][BF4]/MEA混合水溶液的CO2汽液平衡和解吸能耗分析

搭建汽液平衡实验台,对液液分相CO₂吸收剂1-丁基-3-甲基咪唑四氟硼酸盐（[Bmim][BF₄]）/乙醇胺（MEA）混合水溶液与CO₂的汽液平衡进行了实验测量与分析,并对该吸收剂解吸能耗进行计算。结果表明,随着温度的升高,相同担载量溶液对应的CO₂分压升高,[Bmim][BF₄]质量分数的改变对汽液平衡的影响不明显。与传统有机胺溶液30%（质量）MEA相比,该吸收剂在能耗方面主要优势在于解吸过程中显热和潜热的减小。其反应热在担载量大于0.45之后明显减小,潜热的减小主要由于解吸塔内H₂O气相分压和摩尔分数的减小,当[Bmim][BF₄]质量分数大于30%时,显热可以减少30%以上,减少的原因主要为比热容的降低和富液胺浓度的提升。     

离子液体-分子溶剂复合萃取剂脱除水中酚类化合物

构建了疏水性离子液体-分子溶剂复合萃取剂,并研究了其对酚类化合物的萃取性能。结果表明,与纯离子液体萃取剂相比,三己基十四烷基溴化（[P₆₆₆₁₄]Br）-乙酸乙酯复合萃取剂在显著降低萃取剂黏度的同时,获得了较高的酚类溶质分配系数。当萃取剂中[P₆₆₆₁₄]Br摩尔分数为20%时,苯酚的分配系数为345,是纯乙酸乙酯为萃取剂时的5.3倍,是[omim]BF₄、[C₁₂mim]NTf₂等常规疏水离子液体的9~60倍;比纯[P₆₆₆₁₄]Br为萃取剂时的分配系数下降25.3%,黏度却比纯[P₆₆₆₁₄]Br降低99%以上。COSMO-RS研究表明[P₆₆₆₁₄]Br与苯酚之间较强的氢键作用是获得较高苯酚分配系数的关键因素。该复合萃取剂对间苯三酚、4-氯苯酚和2,5-二硝基苯酚等物质也有良好的萃取能力。上述结果为开发兼具良好热力学性能和动力学性能的脱酚萃取剂提供了新的思路。     

固载氨基化离子液体的制备及其对CO2的吸附性能

利用浸渍法将[NH₃P-mim][BF₄]和[MEA]L两种离子液体负载到AC、Al₂O₃和MCM-41上,考察了对CO₂的吸附性能,确定了[NH₃P-mim][BF₄]/AC对CO₂的吸附性能最优。并对[NH₃P-mim][BF₄]/AC考察了不同负载量、不同温度下对CO₂的吸附性能,确定了固载离子液体对CO₂的吸附容量随着负载量的增加而增加,且30℃是固载离子液体吸附CO₂的最佳温度,吸附容量达到0.063 mmol CO₂·(g SILP)^-1。对[NH₃P-mim][BF₄]/AC进行红外和热重两种表征,确定了负载离子液体的结构以及在50℃以下优良的热稳定性。     

超强碱离子液体-有机胺-水复配溶剂高效CO2捕集

CO₂捕集是实现碳减排的重要技术之一。其中，化学吸收法是一种有效的、适用于低CO₂分压的CO₂捕集技术。开发出一种高效、低能耗、环保的吸收剂是该领域的研究难点和热点。离子液体(ILs)作为一类绿色溶剂，在CO₂捕集中具有结构可调节、反应速率快、吸收量高等优势，但存在黏度大、价格昂贵等问题，本工作提出将超强碱离子液体1,8-二氮杂二环[5,4,0]十一碳-7-烯咪唑([HDBU][Im])与单乙醇胺(MEA)复配得到离子液体复配溶剂，来提高吸收剂的CO₂吸收量并降低吸收CO₂后溶剂的黏度。研究了离子液体浓度、吸收温度、CO₂分压等对离子液体复配溶剂捕集CO₂性能的影响，测定了离子液体复配溶剂在不同CO₂负荷下的密度和黏度等物性。结果表明，30wt%MEA+10wt%[HDBU][Im]具有较好的吸收能力，在40℃下，CO₂吸收量达到0.1453 g CO₂     

胆碱脯氨酸/RTILs支撑液膜的CO2/N2分离性能

选用不同种类的室温型离子液体（RTILs）与胆碱脯氨酸离子液体进行混合分别制得[Choline][Pro]/[EMIm][N（CN）₂]、[Choline][Pro]/[bmim][PF₆]以及[Choline][Pro]/[HMIm][NTf₂]混合离子液体,并将其应用于离子液体支撑液膜（SILMs）。考察操作温度、操作压差、RTILs种类和含量对SILMs分离CO₂/N₂性能的影响。结果表明胆碱脯氨酸/RTILs系列SILMs的CO₂通量在343.3～1936.9 barrer之间变化并且CO₂/N₂选择性为10.3～34.8。对CO₂膜过程内在机制探索表明随着[HMIm][NTf₂]离子液体在混合离子液体中比例的增加,总阻力1/K_m会呈现先降低后升高的趋势。与实验现象中随着[HMIm][NTf₂]离子液体在混合离子液体中比例的增加CO₂先升高后降低相符。     

Supported ionic liquid sorbents for CO2 capture from simulated flue-gas

Supported ionic liquid (IL) sorbents for CO₂ capture were prepared by impregnating tetramethylammonium glycinate ([N₁₁₁₁] [Gly]) into four types of porous materials in this study. The CO₂ adsorption behavior was investigated in a thermogravimetric analyzer (TGA). Among them, poly(methyl methacrylate) (PMMA)-[N₁₁₁₁] [Gly] exhibits the best CO₂ adsorption properties in terms of adsorption capacity and rate. The CO₂ adsorption capacity reaches up to 2.14 mmol·g^-1 sorbent at 35℃. The fast CO₂ adsorption rate of PMMA-[N₁₁₁₁] [Gly] allows 60 min of adsorption equilibrium time at 35℃ and much shorter time of 4 min is achieved at 75℃. Further, Avrami's fractional-order kinetic model was used and fitted well with the experiment data, which shows good consistency between experimental results and theoretical model. In addition, PMMA-[N₁₁₁₁] [Gly] remained excellent durability in the continuous adsorption-desorption cycling test. Therefore, this stable PMMA-[N₁₁₁₁] [Gly] sorbent has great potential to be used for fast CO₂ adsorption from flue-gas.     

Stepwise growth of melamine-based dendrimers into mesopores and their CO2 adsorption properties

A series of CO₂ adsorbents were synthesized by functionalizing SBA-15 via stepwise growth of amine-terminated melamine-based dendrimers. The adsorbents contained very high organic loadings (up to 50.3 wt%) relative to previous reports. In addition to that, CO₂ adsorption measurements demonstrated that primary amine groups are the only active groups within these dendritic structures for CO₂ adsorption. The CO₂ adsorption capacities of these adsorbents (except for fourth generation dendrimer functionalized SBA-15) are improved relative to the unfunctionalized SBA-15. The exception is associated with the completely filled pores of this adsorbent.     

肉桂酸型离子液体的合成及其二氧化碳吸收

合成了一系列肉桂酸型功能化离子液体,研究了其CO₂ 吸收性能。结果表明,肉桂酸型功能化离子液体吸收二氧化碳性能良好,其阴离子苯环上的取代基会影响CO₂ 吸收性能。随着温度的升高和压力的降低,其CO₂吸收性能都会降低。同时,该离子液体具有很好的循环稳定性,经过5 次吸收脱附循环,该离子液体仍能保持较高的CO₂ 吸收量。结合红外光谱和其低浓度下CO₂ 的吸收研究发现肉桂酸型离子液体吸收CO₂ 存在着化学作用。     

TEPA负载复合氧化活性炭吸附烟气中的CO2性能

以商业煤基活性炭为原料，经低浓度氧气焙烧、H₂O₂氧化改性，并以四乙烯五胺（TEPA）浸渍，得到胺负载复合氧化活性炭，用于模拟烟道气[(15%(体积)CO₂+85%(体积)N₂）+10%(体积)H₂O]中CO₂吸附。低浓度氧气焙烧后，活性炭的最大比表面积和孔体积分别为1421.82 m²/g、0.83 cm³/g。经复合氧化改性后，活性炭的介孔体积增大，表面含氧官能团增加，使得TEPA负载复合氧化活性炭的CO₂吸附性能提高。焙烧时间为4 h，H₂O₂氧化、负载40%TEPA的样品COAC-4-40TEPA，在60℃时CO₂饱和吸附量最高为2.45 mmol/g，是TEPA负载未改性活性炭AC-40TEPA的2.02倍。经过十次吸附循环后，COAC-4-40TEPA的 CO₂饱和吸附量可维持在92.24%，而TEPA的浸出量仅有0.67%。失活模型研究表明，COAC-4-40TEPA的初始吸附速率常数是AC-40TEPA的1.64倍，且失活速率常数低于AC-40TEPA。     

淀粉基多孔碳材料的制备及其吸附CO2/CH4性能

以淀粉为原料,使用水热法将其碳化后用活化剂KOH对其活化,制备了淀粉基多孔碳材料,并对其进行结构表征和CO₂/CH₄的吸附性能测试,计算吸附热以及材料对CO₂/CH₄的吸附选择性,讨论了碳材料结构对其吸附性能的影响。结果表明：在制备过程中,随着活化剂KOH用量比例的增大,所制得的材料其比表面积和孔容增大,其孔径分布也就越宽。所制得的碳材料其比表面积可达2972 m²·g^-1。这些淀粉基多孔碳材料对水蒸气的吸附等温线呈现出Ⅳ类等温线。所制备材料对CO₂吸附容量主要取决于其孔径小于0.8 nm的累积孔容（Vd < 0.8 nm）。材料的超微孔的孔容越大,其对CO₂吸附容量也越大。所制备的C-KOH-1材料在101325 Pa和298 K条件下,对CO₂的吸附量达到4.2 mmol·g^-1,其对CO₂的吸附热明显高于其对CH₄吸附热,其对CO₂/CH₄吸附选择性为3.7～4.26,同时本文通过对材料的水蒸气吸附等温线进行测试,结果表明所得材料主要表现为中等憎水性,这对材料在实际工况的应用奠定了基础。     

Effect of Zr-SBA-15 support on catalytic functionalities of Mo, CoMo, NiMo hydrotreating catalysts

SBA-15 and ZrO₂ (10–50 wt.%) containing SBA-15 mesoporous materials were prepared by direct and post-synthesis methods. Characterization using low angle XRD, pore size distribution, CO₂ chemisorption indicate that hexagonal mesoporous structure is retained even after ZrO₂ addition (25 wt.%). Mo, CoMo and NiMo catalysts prepared using these supports were examined by XRD, oxygen chemisorption, temperature programmed reduction (TPR). The catalysts were tested for hydrodesulfurization (HDS) of thiophene and hydrogenation (HYD) of cyclohexene. HDS of thiophene for 8%Mo, 3%Co8%Mo, and 3%Ni8%Mo increases with increasing ZrO₂ loading in SBA-15 up to 25 wt.%. Oxygen chemisorption and TPR hydrogen consumption indicated that the molybdenum dispersion and anion vacancies, and catalytic activities are significantly influenced by ZrO₂ content in Zr-SBA-15. A comparison indicated that TiO₂-SBA-15, ZrO₂-SBA-15 supported CoMo catalysts show higher activities for hydrodesulfurization.     

Efficient CO2 adsorption and mechanism on nitrogen-doped porous carbons

In this work, nitrogen-doped porous carbons (NACs) were fabricated as an adsorbent by urea modification and KOH activation. The CO₂ adsorption mechanism for the NACs was then explored. The NACs are found to present a large specific surface area (1920.72– 3078.99 m²·g⁻¹) and high micropore percentage (61.60%–76.23%). Under a pressure of 1 bar, sample NAC-650-650 shows the highest CO₂ adsorption capacity up to 5.96 and 3.92 mmol·g⁻¹ at 0 and 25 °C, respectively. In addition, the CO₂/N₂ selectivity of NAC-650-650 is 79.93, much higher than the value of 49.77 obtained for the nonnitrogen-doped carbon AC-650-650. The CO₂ adsorption capacity of the NAC-650-650 sample maintains over 97% after ten cycles. Analysis of the results show that the CO₂ capacity of the NACs has a linear correlation (R² = 0.9633) with the cumulative pore volume for a pore size less than 1.02 nm. The presence of nitrogen and oxygen enhances the CO₂/N₂ selectivity, and pyrrole-N and hydroxy groups contribute more to the CO₂ adsorption. In situ Fourier transform infrared spectra analysis indicates that CO₂ is adsorbed onto the NACs as a gas. Furthermore, the physical adsorption mechanism is confirmed by adsorption kinetic models and the isosteric heat, and it is found to be controlled by CO₂ diffusion. The CO₂ adsorption kinetics for NACs at room temperature and in pure CO₂ is in accordance with the pseudo-first-order model and Avramís fractional-order kinetic model.     

Surface sol–gel modification of mesoporous silica molecular sieve SBA-15 with TiO2 in supercritical CO2

Mesoporous silica molecular sieve SBA-15 has been grafted with monolayer and doublelayer of titanium dioxide via surface sol–gel process in supercritical carbon dioxide (SC CO₂). The materials were characterized by nitrogen adsorption, X-ray photoelectron, X-ray diffraction (XRD), and Raman spectroscopy. The results suggest that the incorporated titanium dioxide is present mainly as anatase phase. The pore diameter decreases with the modification cycle number, and the titanium dioxide exists as a 5 Å thick film chemically anchored on the mesopores of SBA-15.