碱式碳酸镁催化酚醛聚合制备多孔炭及其CO2吸附性能

利用碱式碳酸镁的催化功能及易分解特性,实现间苯二酚、甲醛的快速凝胶,炭化得到孔隙发达的整体式多孔炭(MCM-Mg),其轴向抗压强度达9.4 MPa。与普通碳酸盐催化的样品相比,MCM-Mg孔隙更为发达。273 K下该系列样品的静态CO₂吸附量可达3.49~4.50 mmol·g^-1 (0.1 MPa),0.015 MPa最高可达1.87 mmol·g^-1。研究发现,微孔对材料吸附性能起主导作用;MCM-Mg的单位微孔比表面积可吸附7.15 μmol CO₂,超过了大部分活化法制备的炭材料。多组分动态穿透实验表明,该系列材料可实现CO₂/N₂的完全分离;材料具有良好的耐水汽性能和循环吸附-脱附性能,室温下经惰性气体吹扫即可实现再生。     

季铵型多孔超交联离子聚合物催化二氧化碳环加成合成环状碳酸酯

以双(三苯基膦)氯化铵为单体，通过傅-克烷基化反应制备一种季铵型多孔超交联离子聚合物(QA-PHIP)。采用傅里叶变换红外光谱、扫描电镜和N₂吸附-脱附等对QA-PHIP进行表征。结果表明，QA-PHIP的比表面积为903.7 m²·g^-1,在0.1 MPa和0℃条件下CO₂的吸附量为52.1 cm³·g^-1。将QA-PHIP应用于催化CO₂与环氧化物合成环状碳酸酯的反应，考察反应温度和催化剂用量等因素对催化性能的影响。QA-PHIP表现出良好的催化性能，在120℃和1.0 MPa条件下反应12 h,可获得99.6%的环氧氯丙烷转化率和97.3%的氯甲基二氧杂戊环酮收率。QA-PHIP表现出良好的底物扩展性和重复使用性。     

拟薄水铝石负载PEI/AMP吸附CO2性能

用富含胺基的物质对多孔材料进行修饰可以得到高CO₂吸附量的吸附剂。采用浸渍法将聚乙烯亚胺(PEI)和2-氨基-2-甲基-1-丙醇(AMP)负载在拟薄水铝石上,考察了CO₂压力、胺类物质负载量等对吸附性能的影响。采用低温N₂吸附/脱附法(BET)、扫描电镜(SEM)、傅里叶变换红外线光谱分析仪(FTIR)等手段表征了吸附剂的结构特征及其物理性质,并使用重量法微天平实验装置对吸附剂的性能进行了评价。实验结果表明,当温度恒定为50℃,压力小于1 MPa时,负载PEI的吸附剂最高的CO₂吸附量为77.53 mg CO₂·(g吸附剂)^-1,最佳负载量为85%;压力大于1 MPa时,负载PEI的吸附剂最高的CO₂吸附量为123.79 mg CO₂·(g吸附剂)^-1,最佳负载量为10%。负载AMP的吸附剂最高的CO₂吸附量为128.01 mg CO₂·(g吸附剂)^-1,最佳负载量为85%。CO₂吸附稳定性实验表明,吸附剂对CO₂的吸附性能稳定。     

利用煤焦油中酚类物质St?ber法制备碳纳米球用于CO2吸附

煤焦油的排放和直接利用会造成严重的环境污染，开发高附加值材料的绿色合成方法及应用是煤焦油利用的关键。本文采用St?ber法以间苯二酚和中低温煤焦油为碳源与甲醛聚合制备了多孔碳纳米球CO₂吸附剂，通过扫描电子显微镜、N₂吸附-脱附测试、傅里叶变换红外吸收光谱、X射线衍射等手段对样品进行测试和分析。考察了预聚温度、水热温度和煤焦油添加量对碳纳米球的孔结构和CO₂吸附性能的影响。预聚温度为60℃、水热温度为200℃时，产物具有最优异的比表面积和CO₂吸附性能。C₁-R₁-RT-200吸附剂的比表面积达到787m²/g,CO₂最大吸附量为4.64mmol/g。当煤焦油占总投料质量的50%～76%时，产物的CO₂吸附性能较好，优于纯的间苯二酚模型化合物。所制备的多孔碳纳米球的CO₂吸附等温线可以很好地吻合Langmuir等温线模型，说明多孔碳纳米球对CO₂的...     

容量法测量5 A分子筛静态吸附CH4、CO和CO2的研究

采用容量法分别测量CH₄、CO和CO₂在5A分子筛上的等温吸附曲线,探究吸附温度和吸附压力对CH₄、CO和CO₂吸附量的影响。实验结果表明,吸附量随着吸附压力的上升逐渐增大。设定吸附温度在30 ℃、50 ℃和70 ℃时,5A分子筛在30 ℃时对CH₄吸附量最大,为13.60 cm³·g^-1;对CO和CO₂吸附量均在50 ℃时呈现最大值,分别为17.68 cm³·g^-1 和94.38 cm³·g^-1。而吸附温度70 ℃时,对3种气体的吸附量均减小。     

用于燃烧前CO2捕集的微孔Nb2O5膜的制备及其水热稳定性能

以五正丁氧基铌为前驱体,通过溶胶-凝胶法制备出稳定的Nb₂O₅聚合溶胶,详细考察了溶胶制备过程参数(体系酸度、水解比、反应温度、反应时间和螯合剂用量)对溶胶尺寸、稳定性以及制备重复性的影响。采用平均粒径为4.8 nm的Nb₂O₅溶胶,通过浸浆法在平均孔径为3 nm的γ-Al₂O₃中孔膜上制备出Nb₂O₅微孔膜。利用TG、XRD、NH₃吸附-脱附、CO₂吸附、吡啶吸附傅里叶变换红外光谱(Py-IR)和单组分气体渗透实验等手段对Nb₂O₅粉体及微孔膜的性能进行了表征,结果表明:在200℃、0.3 MPa条件下,350℃烧成的微孔Nb₂O₅膜对H₂的渗透率和H₂/CO₂的理想分离因子分别为3.1×10^-9 mol·m^-2·s^-1·Pa^-1和21。此外,微孔Nb₂O₅膜经150 kPa的水蒸气处理8 h后,膜的渗透性能以及H₂/CO₂理想选择性基本保持不变。     

CO/N2/CO2在MOF-74(Ni)上吸附相平衡和选择性

主要研究了MOF-74(Ni)材料对CO/N₂/CO₂的吸附分离性能。应用水热法合成制备MOF-74(Ni),分别采用全自动表面积吸附仪、P-XRD、扫描电子显微镜对材料的孔隙结构和晶体形貌进行了表征,应用静态吸附法测定了CO、N₂和CO₂在MOF-74(Ni)上的吸附等温线,应用DSLF方程模拟了3种气体MOF-74(Ni)上的吸附等温线,依据IAST理论模型计算了MOF-74(Ni)对CO/N₂二元混合物和CO/CO₂二元混合物的吸附选择性。研究结果表明:在0.1 MPa和常温条件下,MOF-74(Ni)材料对CO吸附容量高达6.15 mmol·g^-1,而相同条件下N₂的吸附量只有0.86 mmol·g^-1。MOF-74(Ni)在低压下(0～40 kPa)对CO的吸附量明显高于其对CO₂的吸附量。应用IAST模型估算MOF-74(Ni)对二元混合物吸附选择性的结果表明:MOF-74(Ni)对CO/N₂混合物的吸附选择性在1000以上;MOF-74(Ni)对CO/CO₂的吸附选择性在4～9范围,在所研究的二元气体混合物吸附体系中,MOF-74(Ni)都能优先吸附CO。     

温度对MOF-74(Ni)吸附分离丙烯丙烷机理和选择性的影响

采用水热法成功制备了MOF-74(Ni),使用PXRD、孔径分析对材料进行了表征,测定了材料在不同温度下的C₃H₆和C₃H₈吸附等温线,应用程序升温脱附技术估算了脱附活化能,并使用IAST理论预测了材料对C₃H₆/C₃H₈二元体系的吸附选择性。讨论了温度对吸附机理和吸附选择性的影响。结果显示,MOF-74(Ni)的BET比表面积高达1306 m²·g^-1。在298 K下,C₃H₆的吸附量高达7.4 mmol·g^-1。随着温度升高,C₃H₈的吸附量大幅降低,而C₃H₆的吸附量下降程度较小,导致材料对C₃H₆/C₃H₈吸附选择性升高。当温度为328K时,MOF-74(Ni)对C₃H₆/C₃H₈二元气体混合物的吸附选择接近12。程序升温脱附的实验结果显示,C₃H₆在MOF-74(Ni)上的脱附活化能大于C₃H₈,分别为68.92 kJ·mol^-1和50.80 kJ·mol^-1。C₃H₆是通过与MOF-74(Ni)的不饱和金属位点Ni²⁺以p络合作用方式吸附,作用力较强,而C₃H₈与Ni²⁺之间的作用力较弱。根据吸附机理不同的特点,适当提高温度,将有助于提高MOF-74(Ni)吸附分离C₃H₆/C₃H₈混合物体系的吸附选择性。     

不同氨基修饰条件对NH2-MIL-53(Al)CO2吸附性能的影响

采用水热合成法,通过改变配体中2-氨基对苯二甲酸的含量制备了不同氨基含量的NH₂-MIL-53（Al）,考察了氨基含量,氨基功能化方法和氨基种类对NH₂-MIL-53（Al）的CO₂吸附性能的影响。傅里叶变换红外光谱表征（IR）发现在3500～3900 cm^-1处存在-NH₂基的伸缩振动带,氨基修饰成功。低压下,NH₂-MIL-53（Al）的CO₂吸附容量随氨基含量的增加而增大,且当氨基含量100%时,其CO₂吸附性能优于直接合成的NH₂-MIL-53（Al）。合成前修饰比合成后修饰,更有利于提高CO₂吸附容量。采用乙醇胺、1,8-二氮杂二环[5.4.0]十一碳-7-烯、N,N'-二亚乙基三胺进行后氨基功能化都不能提高MIL-53的CO₂吸附能力。     

超枝化固体胺吸附分离烟气中二氧化碳

采用浸渍方法将四乙烯五胺（TEPA）负载到KIT-6介孔硅材料孔道表面上合成超枝化固体胺KIT-6(TEPA),并对其吸附CO₂性能进行研究。结果表明,随着温度的升高,KIT-6(TEPA)的CO₂吸附量呈增长趋势,343 K时获得最大吸附量（3.1 mmol·g^-1）。继续升高温度吸附量则呈下降趋势。KIT-6(TEPA)吸附CO₂过程以化学吸附为主,化学吸附量占总吸附量的97.2%以上（323相似文献   

Preparation and CO2 adsorption of amine modified Mg–Al LDH via exfoliation route

In response to the recent focus on reducing carbon dioxide emission, the preparation and characterization of organically functionalized materials for use in carbon capture have received considerable attention. In this paper the synthesis of amine modified layered double hydroxides (LDHs) via an exfoliation and grafting synthetic route is reported. The materials were characterized by elemental analysis (EA), powder x-ray diffraction (PXRD), diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) and thermogravimetric analysis (TGA). Adsorption of carbon dioxide on modified layered double hydroxides was investigated by TGA at 25–80 °C. 3-[2-(2-Aminoethylamino) ethylamino]propyl-trimethoxysilane modified MgAl LDH showed a maximum CO₂ adsorption capacity of 1.76 mmol g^?1 at 80 °C. The influence of primary and secondary amines on carbon dioxide adsorption is discussed. The carbon dioxide adsorption isotherms presented were closely fitted to the Avrami kinetic model.     

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.     

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     

Preparation of silica xerogel with high silanol content from sodium silicate and its application as CO2 adsorbent

In this study, silica xerogels with high silanol content were synthesized by using sodium silicate as low-cost silica source in the presence of hydrochloric acid and acetic acid via sol–gel process for CO₂ adsorption purpose. The effect of amount of acetic acid on the surface and structural properties of silica xerogel was investigated. Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) revealed that the silanol groups existed on the surface of silica xerogel products and their concentration increased with increasing the amount of acetic acid. The BET surface area and total pore volume of the silica xerogel prepared using 6 mL of acetic acid (MMS-6) were found to be 1021 m²/g and 0.72 cm³/g, respectively. The pore structure of silica xerogel products consisted of the interparticle voids between the nanoparticles aggregates, and the interconnected wormhole microporous structure. The latter pore structure was more uniform on increasing the amount of acetic acid. CO₂ adsorption/desorption measurements were carried out using TGA unit with high purity CO₂ (99.999%). The highest CO₂ sorption capacity (83.6 mg_CO2/g_sorbent) was obtained with MMS-6 product. Thermal swing adsorption studies showed that the silica xerogel products exhibited strongly reversible CO₂ adsorption capacity and stable during 5-repeated cycle of adsorption/desorption experiment at 35 °C.     

Simplified synthesis of layered double hydroxide using a natural source of magnesium

The dolomite is a double carbonate; it is a natural source of calcium and magnesium ions. In this study, Mg–Al–CO₃ layered double hydroxide was synthesized from the dolomite by a simple method. The effect of synthesis parameters, such as M²⁺/Al³⁺ ratio, reaction temperature and pH on their structure, and textural properties were studied. The structure of materials was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and Brunauer, Emmett, and Teller (BET) measurements.     

Simultaneous modification of hydrotalcite–silicate nanolayers as reinforcement of a new polyamide: thermal properties and flammability study

New polyamide/clay–layered double hydroxide nanocomposites (PACLN) were prepared from a synthesized aliphatic–aromatic polyamide (AAPA) and organically modified layered double hydroxide–clay (MLC) nanohybrid. MLC was obtained by simultaneous modification of montmorillonite and hydrotalcite nanolayers with cationic–anionic polyethyleneimine/poly(acrylic acid)-co-poly(2-acrylamido-2-methylpropanesulfonic acid) in an ion-exchange reaction. The analysis results indicated that the modification successfully occurred in MLC with increasing interlayer spacing. PACLN were prepared from AAPA and MLC using the solvent-casting technique. The thermal and combustion properties, morphology and structure of the resulting nanocomposites were studied using thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), scanning and transmission electron microscopies, Fourier transform infrared spectroscopy and X-ray diffraction. The results indicated that the silicate and hydrotalcite nanosheets were dispersed in the AAPA matrix. In other words, the silicate and hydrotalcite nanosheets were placed in the AAPA matrix as a new two-dimensional rearranged structure by self-assembly. The TGA results of nanocomposites in N₂ environment showed that PACLN is more heat resistant than AAPA. The 5% mass degradation temperature of PACLN containing 5 mass% of MLC was obtained as almost 60 °C more than that of AAPA. According to MCC results, the peaks of heat release rate were reduced from 156 to 91 W g⁻¹ for AAPA containing 5 mass% of MLC. © 2022 Society of Industrial Chemistry.     

Causticization of sodium carbonate with rock-salt type magnesium aluminium oxide formed by the thermal decomposition of hydrotalcite-like layered double hydroxide

The causticization behaviour of Na₂CO₃ with rock-salt type oxide, Mg_2(1-x/(2+x) O (M = Al³⁺ and Fe³⁺, x = 0.2 and 0.33), produced by the thermal decomposition of hydrotalcite-like layered double hydroxide was investigated at 30–60°C. The degree of causticization increased with increasing the molar ratio of [rock-salt type oxide]/[Na₂CO₃] and increasing the temperature but decreased with increasing the initial concentration of Na₂CO₃. The causticization behaviour could be adequately described by the equation of anion exchange equilibria between CO₃^2- and OH^? for layered double hydroxide.     

Surface functionalization of SBA-15 nanorods for anticancer drug delivery

SBA-15 nanorods with high surface area (1010 m² g⁻¹) were functionalized by post grafting method with three different alkoxysilanes including (3-aminopropyl) triethoxysilane (APTES), 3-[bis(2-hydroxyethyl)amino] propyl triethoxysilane (HAPS) and 3-[2-(2-aminoethylamino) ethylamino] propyl trimethoxysilane (AEPS). The prepared materials were used as nanocarriers for an anticancer drug (gemcitabine). The obtained samples were characterized by SAXS, elemental analysis, TGA, N₂ adsorption/desorption, SEM, TEM, FTIR and UV spectroscopies. The adsorption and release properties of all samples were investigated. It was found that the surface functionalization increases the interaction between the carrier and gemcitabine and results in the loading enhancement of the drug. In addition, the adsorption of gemcitabine on the modified mesoporous matrix depends on the type and the amount of alkoxysilanes groups. The maximum content of the deposited drug in the modified SBA-15 nanorods is close to 22 wt.%. The rate of the drug release from the modified samples containing NH₂ groups on their surfaces is pH dependent.