1-氨丙基-3-甲基咪唑溴功能型离子液体对CO2的吸收性能

1-氨丙基-3-甲基咪唑溴盐([APMIm])对CO₂等酸性气体具有较强的选择性吸收性能,在能源及环保领域有较好应用前景。运用等容饱和吸收法在高压不锈钢反应釜中测得CO₂在3种不同含水量的1-氨丙基-3-甲基咪唑溴盐水溶液中的溶解度数据,实验的温度范围为278.15~348.15 K,实验压力由低于大气压到最高6.5 MPa。实验结果表明,当水的质量分数达到60.84%以上,离子液体水溶液吸收CO₂的能力和速率才会得到显著提升。尤其值得注意的是,在278.15 K、120 kPa达到吸收平衡时,CO₂在含水质量分数为60.84%的1-氨丙基-3-甲基咪唑溴盐水溶液中的溶解度达到0.459 mol CO₂ ·(mol IL)^-1,接近理论最大吸收值0.5 mol CO₂·(mol IL)^-1。在较高压力下(3.9 MPa)最大CO₂吸收量为1.894 mol CO₂·(mol IL)^-1。     

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。     

氨水吸收CO2的吸收热预测模型

基于e-NRTL模型,利用Aspen Plus软件建立了氨水吸收CO₂的吸收热预测模型,验证了NH₃-CO₂-H₂O体系的汽液平衡、液相组成形态并与前人的实验数据做了对比,进而结合负载CO₂的氨水溶液中各离子及分子的变化特征,对CO₂吸收过程的反应热随着CO₂负载量的变化规律进行了预测并与已发表的数据进行了比较。结果表明,该吸收热模型能够准确地实现氨水吸收CO₂过程中汽液平衡、液相反应以及吸收热的计算。氨水吸收CO₂的反应热主要受H₂O的电离、NH₃的电离、NH₂COO^-的生成与水解、CO₂的溶解等反应过程的影响,H₂O的电离过程受NH₃的电离过程的抑制,对于总吸收热的贡献最大, NH₂COO^-的反应则随着CO₂负载量的增加先放热再吸热。随着温度的升高,总吸收热有所降低,当温度为80℃时,在较低的CO₂负载区间[0.2～0.5 mol CO₂·(mol NH₃)^-1],总吸收热约为70.5 kJ·(mol CO₂)^-1。     

Na2CO3基吸附剂颗粒制备及其脱碳性能

采用挤压-滚圆法制备Na₂CO₃基CO₂吸附剂微球颗粒,在自行设计的CO₂吸收系统中对制备的样品进行脱碳性能测试。结合相关表征测试,探明不同载体、不同负载量的Na₂CO₃基吸附剂的微观结构、脱碳性能以及机械性能的变化规律和内在原因。研究表明：不同载体的Na₂CO₃基吸附剂颗粒脱碳性能存在明显差异,其中氧化铝负载的吸附剂（Na₂CO₃/Al₂O₃）的脱碳性能最好,可达1.14mmol/g。铝酸钙水泥负载的吸附剂（Na₂CO₃/CA）机械性能较好,但其脱碳性能最差。结合吸附剂脱碳和机械性能的综合考量,Na₂CO₃/Al₂O₃是最为合适的CO₂吸附剂,并进一步研究不同Na₂CO₃负载量的影响。研究发现随着Na₂CO₃负载量的变化,吸附剂的微观结构、脱碳性能以及机械性能都存在明显的差异。虽然60%负载量的Na₂CO₃/Al₂O₃吸附剂颗粒的机械性能和脱碳效果较好,但其成球度较差,影响其实际应用。质量分数40%负载量的Na₂CO₃/Al₂O₃吸附剂颗粒具有良好的脱碳性能、机械性能以及成球度,CO₂脱除量为1.36mmol/g。总体而言,利用挤压-滚圆法制备的Na₂CO₃基吸附剂颗粒具有良好的流动特性、脱碳性能和机械性能,适用于电厂烟气中的CO₂脱除。     

Zn(OAc)2/AC催化固定床上CO2与1,2-丙二醇合成碳酸丙烯酯及其反应机理

以负载型乙酸锌为催化剂,在固定床上实现了CO₂和1,2-丙二醇(PG)合成碳酸丙烯酯(PC)反应。考察了不同载体和负载量对负载型乙酸锌催化性能的影响以及反应条件对PC合成反应的影响。结果表明:负载量为40% (质量分数)的Zn(OAc)₂/AC催化性能最好。CO₂与PG合成PC适宜的反应条件为:PG、乙腈和CO₂的摩尔比为1:1.8:11,CO₂ 压力 4.0 MPa,反应温度160 ℃和液空速0.9 h^-1。在此条件下,PC收率和选择性分别为6.3%和49.0%。采用原位红外结合设计实验研究了无水乙酸锌分别与CO₂和PG之间的相互作用,发现CO₂与乙酸锌之间的化学吸附比较弱,而PG与乙酸锌之间的化学吸附较强,能够活化PG。据此推测了乙酸锌催化CO₂与PG合成PC的反应机理。     

CO2在PET熔体中的溶解度

通过高温高压磁悬浮天平(MSB)测定表观溶解度、高温高压视窗釜进行溶胀度校正的方法研究了CO₂在PET熔体中的溶解度,考察了温度、压力对改性前后PET在CO₂环境中的溶胀度和CO₂溶解度的影响。结果表明,PET在CO₂环境中的溶胀度和CO₂溶解度均随温度的增加而减小,随压力增加而增加,但高压下溶胀度的增加趋势减缓并趋于某定值;与常规线性PET相比,改性PET具有较小的溶胀度和溶解度。在250~280℃,4~6 MPa下,CO₂在PET熔体中的溶解度具有10^-2 g CO₂·(g PET melt)^-1的量级。1~6 MPa下CO₂在PET熔体中的溶解行为符合亨利定律,利用最小二乘法拟合得到了CO₂在PET熔体中的溶解热。     

PEI改性SBA-15吸附分离COS/N2

聚乙烯亚胺(PEI)改性SBA-15的吸附剂用于脱除低浓度羰基硫(COS),吸附剂采用XRD、化学吸附仪和红外光谱进行表征.PEI改性SBA-15后,SBA -15结构没有太大变化,比表面积有所下降,吸附过程中存在化学吸附.在28℃下,PEI负载量为50％(质量分数)时对COS吸附效果最佳,穿透吸附量可达5.383 mg/g,饱和吸附量可达11.698 mg/g;60℃为最佳吸附温度,穿透吸附量可达11.724 mg/g,饱和吸附量可达32.38 mg/g;吸附剂可在100℃下用氮气吹扫再生.     

H2S对铝基固态胺吸附剂吸附CO2性能的干扰机制

H₂S杂质对固态胺吸附剂吸附CO₂性能的干扰机制还缺少全面研究。以Al₂O₃为载体负载聚乙烯亚胺(PEI)制备铝基固态胺吸附剂(PEI@Al₂O₃),系统探究了H₂S对其CO₂吸附容量、吸附速率和循环吸附性能的影响规律。结果表明：H₂S与CO₂共存时,会相互抢占吸附剂上的胺基活性位点,从而发生竞争性吸附,但在模拟沼气条件(40%CO₂+59.5%CH₄+0.5%H₂S)下,H₂S的吸附竞争力远小于CO₂,H₂S吸附被抑制,且二者的最佳吸附温度不一致,在CO₂最佳吸附温度下,PEI@Al₂O₃的CO₂吸附容量和循环稳定性均不受H₂S干...     

镍铈改性甘蔗基活性炭吸附二氧化硫研究

以甘蔗为前驱体，制备了甘蔗基活性炭，并通过Ni O、Ce O₂进行改性，对SO₂进行吸附实验研究，结果表明，Ni O、Ce O₂的加入对甘蔗基活性炭的比表面积增大、吸附量的提高具有有利影响，Ni O的最佳添加量为2.5%,Ce O₂的最佳添加量为5%，吸附剂最佳吸附应条件为：吸附温度为60℃，SO₂初始浓度为1000×10^-6，空速为1200h^-1。在最佳反应条件下，2.5%NiO/5.0%CeO₂-甘蔗基活性炭的SO₂吸附量为56.39m²·g^-1。     

燃煤烟气中SO2对氨法脱碳的影响

利用湿壁塔实验台对燃煤烟气中SO₂对氨水溶液［1%～7%(质量）］吸收CO₂的影响进行了实验研究,具体分析了不同反应温度（20～80℃）和CO₂体积分数（5%～20%）条件下,CO₂传质通量及传质系数随SO₂浓度和SO₂负载量的变化规律。结果表明, SO₂浓度由0增至11428 mg·m^-3,CO₂传质通量及传质系数均有一半左右降幅,而SO₂负载量［0.1～0.4 mol SO₂·（mol NH₃）^-1］的增加,同样导致CO₂传质通量及传质系数明显减小。氨水浓度及反应温度增加可有效提高CO₂传质通量和传质系数,相对降低SO₂对CO₂传质的影响。CO₂浓度的增加可明显提高其传质通量,但是CO₂的传质系数有所降低。     

CO2 adsorption performance of polyethyleneimine-modified ion-exchange resin

A series of solid amine adsorbents were prepared by the template method with ion-exchange resin (D001) as the carrier and polyethyleneimine (PEI) as the modifier. The absorbents were characterized by energy disperse spectroscopy (EDS), scanning electron microscope (SEM), N₂ adsorption–desorption, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) techniques. The effects of PEI loading, adsorption temperature and influent velocities on CO₂ adsorption capacity in a fixed-bed reactor were investigated. The results show that the solid amine adsorbent prepared by the template method had a better PEI dispersion, stability and CO₂ adsorption capacity. The maximum CO₂ adsorption capacity was 3.98 mmol·g^?1 when PEI loading was 30%, the adsorption temperature was 65°C and the influent velocity was 40 mL·min^?1. The CO₂ adsorption capacity decreased only by 9.50% after 10 cycles of adsorption–desorption tests. The study of kinetics indicates that both chemical adsorption and physical adsorption occurred in the CO₂ adsorption process. The CO₂ adsorption process included fast breakthrough adsorption and gradually approaching equilibrium stage. The particle internal diffusion process was the control step for CO₂ adsorption.     

Amine modified mesocellular siliceous foam (MCF) as a sorbent for CO2

Adsorption is considered a promising method for carbon capture. CO₂ adsorbents take a variety of forms - but one approach is to fill mesoporous substrates with a polymeric CO₂ selective sorbent. SBA-15 and mesocellular siliceous foam (MCF) are high pore volume, high surface area ordered mesoporous materials for which modification with amine should result in high capacity, highly selective adsorbents. SBA-15 and MCF were separately loaded with approximately one pore volume equivalent of linear polyethyleneimine (PEI) (M_w = 2500) or branched PEI (M_n = 1200). CO₂ adsorption/desorption isotherms under dry CO₂ were obtained at 75, 105 and 115 °C. The CO₂ adsorption/desorption kinetics were improved with temperature, though the CO₂ capacities generally decreased. The adsorption capacity for MCF loaded with branched PEI at 105 and 115 °C were 151 and 133 mg/g adsorbent, respectively (in 50% CO₂/Ar, 20 min adsorption time). These are significantly higher than the adsorption capacity observed for SBA-15 loaded with branched PEI under same conditions, which were 107 and 83 mg/g adsorbent, respectively. Thus the results indicate that, on a unit mass basis, amine modified MCF's are potentially better adsorbents than amine modified SBA-15 for CO₂ capture at modestly elevated temperature in a vacuum swing adsorption process.     

Preparation and adsorption properties of polyethylenimine containing fibrous adsorbent for carbon dioxide capture

We successfully prepared a novel fibrous adsorbent for carbon dioxide (CO₂) capture by coating polyethylenimine (PEI) on a glass fiber matrix, using epoxy resin (EP) as crosslinking agent. The physicochemical properties of the fibrous adsorbents were characterized in terms of Fourier transform infrared spectrometry and thermogravimetric analysis. Factors that affected the adsorption capacity of the fibrous adsorbent were studied, including the crosslinking agent dosage, coating weight, moisture, adsorption temperature, and CO₂ concentration of the simulated flue gas. The experimental results indicate that the properly crosslinked fibrous adsorbent had a high thermal stability at about 280°C. With a PEI/EP ratio of 10:1, a maximum adsorption capacity of 276.96 mg of CO₂/g of PEI was obtained at 30°C. Moisture had a promoting influence on the adsorption of CO₂ from flue gas. The CO₂ adsorption capacity of the fibrous adsorbent in the presence of moisture could be 19 times higher than that in dry conditions. The fibrous adsorbent could be completely regenerated at 120°C. The CO₂ adsorption capacity of the regenerated fibrous adsorbent was almost the same as that of the fresh adsorbent. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

CO2 adsorption on amine-modified mesoporous silicas

Mesoporous silicas with enhanced pore structures were synthesized and polyethylenimine (PEI) was immobilized in them to produce adsorbents for CO₂. The prepared samples were characterized by N₂ adsorption–desorption isotherms and small angle X-ray diffraction, and their CO₂ adsorption performance were evaluated. CO₂ adsorption capacity increased with operating temperature initially and then decreased. Besides, CO₂ adsorption capacity increased due to the PEI loading with more amine sites. The results showed that the structure of support played an important role in the CO₂ adsorption capacity. High surface area and large pore volume also favored the CO₂ adsorption capacity.     

Adsorption behavior and kinetics of CO2 on amine-functionalized hyper-crosslinked polymer

A hyper-crosslinked polymer (XAD-4-pc) was developed by modifying the commercial polystyrene resin (XAD-4) through a Friedel–Crafts reaction, followed by impregnation with polyethyleneimine (PEI) for CO₂ capture. The physicochemical properties of the as-synthesized adsorbents were analyzed by different characterization techniques, and the adsorption behavior of CO₂ on these adsorbents was evaluated in a self-assembled adsorption setup with gas chromatography. Experimental results found that the Brunauer–Emmett–Teller surface area and pore volume of XAD-4-pc were significantly higher than that of XAD-4, which was favorable to the improvement of PEI loading and CO₂ adsorption. The maximum CO₂ uptake for PEI-functionalized XAD-4-pc was 3.24 mmol g⁻¹ at 25 °C. The adsorption isotherm of CO₂ on the adsorbent was well described by the Langmuir equation, and the kinetics data could be accurately described by Avrami model over the entire adsorption range. The diffusion mechanism study showed that the film diffusion and intraparticle diffusion were mainly the rate-limiting steps. Moreover, this adsorbent could be well regenerated at relatively low temperature and exhibited stable regenerability after five adsorption-regeneration cycles, showing its high potential for the capture of CO₂ from flue gases. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48479.     

CO2 capture of amino functionalized three-dimensional worm-hole mesostructured MSU-J silica

Tetraethylenepentamine (TEPA) was employed to functionalize the large-pore mesoporous silica (denoted MSU-J) with 3D worm-hole framework structures which was prepared through a supramolecular hydrogen-bonding assembly pathway from low-cost H₂NCH(CH₃)CH₂[OCH₂CH(CH₃)]₃₃NH₂ (D2000) as structure-directing porogens and tetraethylorthosilioate as the silica source for capturing CO₂. The resultant adsorbents were characterized by FT-IR, Transmission electron microscopy (TEM), N₂ adsorption/desorption and thermogravimetric analysis. Textural properties, elemental analysis and TEM measurement of the samples showed a severe pore filling of MSU-J as TEPA loading was increased to 70 wt%. CO₂ adsorption isotherms measured at different temperatures revealed the optimal adsorption temperature is 25 °C. The adsorption capacity of MSU-J with different TEPA loading contents was calculated. As a result, 50 wt% of TEPA supported on as-synthesized MSU-J achieved the highest capacity with the value of 164.3 mg/g under the conditions of 99.99 % CO₂ at 25 °C and 0.1 MPa. Repeated adsorption/desorption cycles revealed that amine-impregnated materials was very efficient for less apparent decrease in CO₂ adsorption capacity even after 6 adsorption–regeneration cycles.     

CO2 sorption performance by aminosilane functionalized spheres prepared via co‐condensation and post‐synthesis methods

Amine functionalized silica microspheres were synthesised via a modified Stöber reaction for carbon dioxide (CO₂) adsorption. A number of adsorbents were synthesized by co‐condensation and post synthesis immobilization of amines on porous silica spheres. CO₂ adsorption studies were carried out on a fixed bed gas adsorption rig with online mass spectrometry. Amine co‐condensed silica spheres were found to adsorb up to 66 mg CO₂ g^?1 solid in a 0.15 atm CO₂ stream at 35°C. Simple post‐synthesis addition of aminopropyltriethoxysilane to amine co‐condensed silica was found to significantly increase the uptake of CO₂ to 211 mg CO₂ g^?1 under similar conditions, with CO₂ desorption commencing at temperatures as low as 60°C. The optimum temperature for adsorption was found to be 35°C. This work presents a CO₂ adsorbent prepared via a simple synthesis method, with a high CO₂ adsorption capacity and favorable CO₂ adsorption/desorption performance under simulated flue gas conditions. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2825–2832, 2016     

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。     

Carbon dioxide capture under postcombustion conditions using amine-functionalized SBA-15: Kinetics and multicyclic performance

ABSTRACT

In this work, ordered mesoporous SBA-15 was synthesized and functionalized by polyethyleneimine (PEI). The morphological properties were characterized by N₂ adsorption/desorption, field–emission scanning electron microscopy (FE-SEM), high–resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FTIR) spectroscopy methods. The carbon dioxide (CO₂) uptake on the sorbents, kinetics of CO₂ adsorption/desorption and long-term multicycle stability of PEI-impregnated sorbent were measured. An optimal amine loading of 50 wt.% showed a CO₂ adsorption capacity ~3.09 mmol g^?1 using 10% pre-humidified CO₂ at 75°C. The presence of moisture in flue gas showed a promoting effect in CO₂ sorption capacity. The temperature swing adsorption/desorption cycles showed excellent multicycle stability over 60 cycles during 65 h of operations under humid CO₂.     

Investigation of CO2 adsorption by bagasse-based activated carbon

Bagasse-based activated carbon (BAC) and amine-modified BAC were prepared and investigated for CO₂ adsorption capacity. Modifying BAC with amines resulted in a decrease of surface area, but the decreasing magnitude varied depending on type and loading rate of amines. At room temperature, the unmodified BAC was able to adsorb more CO₂ than the amine-modified BAC. This ability was related to the higher surface area of unmodified than that of the modified BAC. When temperature increased, CO₂ adsorption capacity of all absorbents was decreased. However, above 323 K and a concentration of CO₂ lower than 30% v/v, the BAC modified with PEI at 5 and 25 wt% showed higher adsorption capacity. Among all adsorbents under 15% CO₂ and 348 K, BAC-PEI25 showed the highest adsorption capacity (0.20 mmol/g).