Kinetics of CO2 absorption into a novel 1‐diethylamino‐2‐propanol solvent using stopped‐flow technique

A stopped‐flow apparatus was used to measure the kinetics of carbon dioxide (CO₂) absorption into aqueous solution of 1‐diethylamino‐2‐propanol (1DEA2P) in terms of observed pseudo‐first‐order rate constant (k_o) and second‐order reaction rate constant (k₂), in this work. The experiments were conducted over a 1DEA2P concentration range of 120–751 mol/m³, and a temperature range of 298–313 K. As 1DEA2P is a tertiary amine, the base‐catalyzed hydration mechanism was, then, applied to correlate the experimental CO₂ absorption rate constants obtained from stopped‐flow apparatus. In addition, the pK_a of 1DEA2P was experimentally measured over a temperature range of 278–333 K. The Brønsted relationship between reaction rate constant (obtained from stopped‐flow apparatus) and pK_a was, then, studied. The results showed that the correlation based on the Brønsted relationship performed very well for predicting the absorption rate constant with an absolute average deviation of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3502–3510, 2014     

Amine‐functionalized mesoporous silica: A material capable of CO2 adsorption and fast regeneration by microwave heating

The surface of ordered mesoporous (MCM‐48) silica has been subjected to covalent grafting with silane molecules containing one to three amino groups. The dielectric properties of the materials were studied in detail, and the functionalized materials were used for CO₂ adsorption at room temperature, followed by regeneration under either conventional heating or microwave irradiation. It has been found that, as the intensity of functionalization with amino groups increases (from mono‐ to tri‐amino silanes) both the CO₂ load and the dielectric response at microwave frequencies increase. In particular, functionalization with a tri‐amino silane derivative gave the highest CO₂ adsorption and the fastest microwave heating, resulting in a fourfold acceleration of adsorbent regeneration. The grafted material was fully stable for at least 20 adsorption‐regeneration cycles, making it an ideal candidate for microwave‐swing adsorption (MWSA) processes. © 2015 American Institute of Chemical Engineers AIChE J, 62: 547–555, 2016     

Exploring Potential Methods for Anchoring Amine Groups on the Surface of Activated Carbon for CO2 Adsorption

Activated carbon can be effectively modified for CO₂ adsorption with amine groups due to their high affinity for CO₂. Using approaches such as impregnation, some modifiers containing amine groups are physically adsorbed on the surface of carbon, whereas other amine groups can be directly or indirectly chemically bound to the activated carbon matrix. In the context of exploring potential techniques for grafting amine groups onto activated carbon surfaces, we herein review the literature on modifications applied to different materials and supports for a variety of applications, limited to neither activated carbon nor CO₂-adsorption applications. We focus on the processes of grafting amine groups and the parameters influencing these processes. Moreover, the mechanism of CO₂ adsorption involving amine groups is discussed.     

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     

PtZn‐ETS‐2: A novel catalyst for ethane dehydrogenation

Catalysts having unprecedented selectivity toward ethane dehydrogentation were prepared by combining platinum and zinc on the surface of the titanate ETS‐2. This high surface area, sodium titanate ion exchanger affords high metal dispersion, presents many active sites to the gas stream, and is free of any pore structure that can influence mass transfer to and away from the active sites. It was determined that the addition of zinc to platinum‐loaded ETS‐2 changes the electronic properties of the metals and significantly improves the specificity of the catalyst. By changing the zinc‐to‐platinum ratio, and by manipulating the space velocity of the gas, the production of side products and coke can be suppressed or eliminated. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4367–4376, 2015     

Vapour–liquid equilibrium of CO2 in aqueous solutions of N‐methyl‐2‐ethanolamine

The equilibrium solubility of CO₂ into aqueous solution of sterically hindered N‐methyl‐2‐ethanolamine or methyl amino ethanol (MAE) was investigated in the temperature range of 303.1–323.1 K and total CO₂ pressure in the range of 1–350 kPa. The N‐methyl‐2‐ethanolamine aqueous solutions studied were 0.968, 1.574, 2.240 and 3.125 mol kg^?1 of solvent. © 2011 Canadian Society for Chemical Engineering     

有机胺功能化介孔固体吸附剂吸附分离CO2性能研究

针对当前固体胺CO₂吸附剂存在吸附容量小、循环稳定性差等问题,采用高比表面积、易嫁接胺的介孔SBA-15作为载体,研究分子筛模板剂脱除方法和有机胺改性方法对制备的固体吸附剂吸附性能的影响,并采用N₂物理吸附、X射线衍射、红外光谱、热失重分析等表征技术并对样品进行表征。实验结果表明,通过嫁接和浸渍能够合成出不同有机胺负载量的胺功能化吸附剂,其中混合胺嫁接法改性的APTES-SBA（U）-T60吸附剂其吸附容量最大,在75℃下的纯CO₂气氛中吸附量达到192.05 mg/g,优于溶剂萃取和煅烧法去除模板剂。此外,混合胺嫁接法制备的样品在多次的吸/脱附操作下,CO₂吸附稳定性良好,表明混合胺修饰的吸附剂具有很好的稳定性和再生性。     

Screening CO2/N2 selectivity in metal‐organic frameworks using Monte Carlo simulations and ideal adsorbed solution theory

Selective adsorption of CO₂ over N₂ is important in the design and selection of adsorbents such as metal‐organic frameworks (MOFs) for CO₂ capture and sequestration. In this work, single‐component and mixture adsorption isotherms were calculated in MOFs using grand canonical Monte Carlo (GCMC) simulations at conditions relevant for CO₂ capture from flue gas. Mixture results predicted from single‐component isotherms plus ideal adsorbed solution theory (IAST) agree well with those calculated from full GCMC mixture simulations. This suggests that IAST can be used for preliminary screening of MOFs for CO₂ capture as an alternative to more time‐consuming mixture simulations or experiments. © 2011 Canadian Society for Chemical Engineering     

改性蜂窝状活性炭吸附二氧化碳和氮气的热力学

蜂窝状活性炭具有较高的比表面积、多孔道、压降低、吸脱附速率快、不易堵塞等优点,因此被认为是捕集烟道气中CO₂重要吸附材料。选用蜂窝状煤基和椰壳两种活性炭吸附剂,采用磁悬浮热天平分别测定了CO₂和N₂的吸附等温线。采用1 mol·L^-1 K₂CO₃对蜂窝状活性炭材料进行浸渍改性,提高在低二氧化碳分压下的CO₂吸附性能。采用Langmuir、multi-site Langmuir和Virial 3种模型对吸附平衡数据进行拟合,得出热力学参数,为后续吸附工艺优化设计提供基础数据。结果表明在实验范围内3种模型均能对实验测量的等温线进行较好的拟合,Langmuir模型总体拟合效果最好。     

二氧化碳捕集技术研究进展

随着全球工业的快速发展,二氧化碳的大量排放被认为是造成气候变暖最主要原因,二氧化碳的捕集和封存已经成为研究的热点,本文综述了近年来CO2捕集技术的研究进展,主要有燃烧后捕集、燃烧前捕集和富氧燃烧三条技术路线,最后提出了可以提高二氧化碳捕集能力的策略与展望。     

Radiation grafting of acrylic acid and N‐vinyl imidazole onto polyethylene films for lead‐ion removal: A two‐dimensional correlation infrared spectroscopy investigation

Two‐dimensional infrared (IR) correlation spectroscopy was used to follow the γ‐radiation grafting of N ‐vinyl imidazole (VIm) and acrylic acid onto polyethylene films. Grafting was confirmed by the appearance of new characteristic IR bands at 1715, 1735, 1475, and 1405 cm^?1, which were assigned to carboxylic groups and the stretching vibrations of aromatic C?N and C? N bonds, respectively. The adsorption of lead ions by the grafted polymer increased with the degree of grafting, and it showed a tendency to be altered by both the chemical structure of the matrix polymer and the steric hindrance of Pb²⁺ ions. The previous two factors decreased the basic chelating group activity, imposed steric constraints on the formation of complexes between the Pb²⁺ and VIm groups, and controlled the coordination of Pb²⁺ with the ? COO^? groups. IR spectroscopy combined with two‐dimensional correlation spectroscopy provided a powerful tool for investigating the interactions between heavy metals and functional groups. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44781.     

超临界CO2协助固相接枝改性聚丙烯的研究进展

介绍了超临界CO2协助单体固相接枝聚丙烯的研究方法以及采用此方法,在不同温度、压力和时间的条件下,超临界CO2对接枝改性聚丙烯性能的影响。     

Versatile Synthesis of Pyrrole‐2‐acetic Esters and (Pyridine‐2‐one)‐3‐acetic Amides by Palladium‐Catalyzed,Carbon Dioxide‐Promoted Oxidative Carbonylation of (Z)‐(2‐En‐4‐ynyl)amines

The oxidative carbonylation of readily available (Z)‐(2‐en‐4‐ynyl)amines, catalyzed by the PdI₂‐KI system, selectively afforded in satisfactory yields (40–95 %) either pyrrole‐2‐acetic ester or (pyridine‐2‐one)‐3‐acetic amide derivatives, depending on the susbtitution pattern of the substrate and the reaction conditions. The presence of an excess of carbon dioxide proved in most cases to be beneficial to both the reaction rate and product selectivity.     

Technico‐economical assessment of MFI‐type zeolite membranes for CO2 capture from postcombustion flue gases

A detailed survey of the effect of moisture on the CO₂/N₂ permeation and separation performance of Mobile Five (MFI) zeolite membranes in view of downstream postcombustion CO₂ capture applications in power plants and incinerators is presented. The membranes, displaying a nanocomposite architecture, have been prepared on α‐alumina tubes by pore‐plugging hydrothermal synthesis at 443 K for 89 h using a precursor clear solution with molar composition 1 SiO₂:0.45 tetrapropylammonium hydroxide:27.8 H₂O. The synthesized membranes present reasonable permeation and CO₂/N₂ separation properties even in the presence of high water concentrations in the gas stream. A critical discussion is also provided on the technico‐economical feasibility (i.e., CO₂ recovery, CO₂ purity in the permeate, module volume, and energy consumption) of a membrane cascade unit for CO₂ capture and liquefaction/supercritical storage from standard flue gases emitted from an incinerator. Our results suggest that the permeate pressure should be kept under primary vacuum to promote the CO₂ driving force within the membrane. © 2011 American Institute of Chemical Engineers AIChE J, 58: 3183–3194, 2012     

改性活性炭吸附脱除二氧化碳中微量乙烷

我国对食品级二氧化碳要求较高,在其生产过程中乙烷的脱除是难点。文章首先考察了市售的不同吸附剂,包括Y型、X型、A型等分子筛类,椰壳和煤基活性炭以及吸附树脂等吸附剂对CO2中微量C2H6的吸附效果,之后考察了不同浓度盐酸酸改性与氢氧化钠碱改性、双氧水氧化改性、氨水还原改性等改性条件对吸附剂吸附性能的影响。研究表明,具有高比表面积、丰富微孔和适量中孔结构的活性炭更有益于二氧化碳中微量乙烷的吸附;浓度为1%的盐酸溶液浸渍活性炭3 h后,能增强其对CO2中微量C2H6的吸附能力;浓度3%、浸渍时间6 h为氢氧化钠碱溶液改性活性炭的最佳条件;弱氧化剂双氧水改性能略微提高活性炭对二氧化碳中乙烷的吸附能力,弱还原剂氨水改性对吸附效果无明显影响。     

Sulfated katira gum‐graft‐poly(N‐vinyl imidazole): A useful scavenger of mercury(II) ions

Katira gum-graft-poly(N-vinyl imidazole) was synthesized in a water medium with potassium perdisulfate as the free-radical initiator at 70 ± 1 °C. The graft copolymer was sulfated by chlorosulfonic acid in the presence of pyridine and formamide. Various characterization techniques, including Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy, were used to characterize both the unsulfated and sulfated graft copolymers. The sulfated graft copolymer was used for the adsorption of Hg(II) ions from its aqueous solution. The operating variables affecting the Hg(II) adsorption, including the solution pH, amount of sulfated graft copolymer, contact time, and concentration of Hg(II), were investigated extensively. The sulfated graft copolymer was also used for competitive metal-ion removal with Pb(II), Cd(II), Cu(II), and Zn(II). Metal complexation was studied with FTIR spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and cyclic voltammetry analysis. The Hg(II) adsorption data of the sulfated graft copolymer were described well by the pseudo-second-order rate equation. The Langmuir adsorption isotherm provided the best correlation for the adsorption data. Various thermodynamic parameters for the adsorption were calculated. FTIR and UV–vis spectroscopy and cyclic voltammetry analysis before and after the adsorption of Hg(II) on the sulfated graft copolymer showed that columbic attraction was mainly responsible for the binding of the Hg(II) ions with the  groups present in the sulfated graft copolymer. The sulfated graft copolymer showed a better adsorption performance than the graft copolymer itself under optimized conditions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44565.     

Theoretical analysis and experimental study on SO2 adsorption onto pistachio‐nut‐shell activated carbon

The adsorption study of SO₂ onto the activated carbon prepared from pistachio‐nut shell was studied theoretically and experimentally. A single‐particle sorption model known as concentration‐dependent surface diffusivity micropore, surface and macropore diffusion control model incorporating micropore, macropore and surface diffusions, together with a nonlinear isotherm at the micropore mouth, has been derived and solved by a finite difference method. The effects of different types of nonlinear isotherms and concentration dependent surface diffusivities have been thoroughly studied. The effects of adsorbate concentration and temperature on adsorption were studied experimentally. Good agreement was found between the model predictions and the experimental results. The value of the tortuosity factor and the extracted diffusion coefficients obtained are consistent with their corresponding values reported. © 2008 American Institute of Chemical Engineers AIChE J 2009