不同类型生物炭对CO2吸附性能及其机理

本研究以5种生物质为原料制备了生物炭,并对其进行理化表征,考察了生物炭对CO₂的吸附性能及机理。结果表明,椰壳(YK)、松木(SM)生物炭的比表面积是玉米芯(YM)、芦苇秆(LW)、椰衣(YY)生物炭的1.99～2.90倍。YK、SM对CO₂的吸附量(108.78～118.89 mg/g)高于YM、LW、YY(95.33～105.55 mg/g)。此外,YK中较高的S含量(2.17%)与碱度对CO₂吸附也起着促进作用。研究发现,生物炭的比表面积、孔径、碱度、官能团均是影响CO₂吸附的重要因素,当孔隙差异明显时,孔隙结构对CO₂吸附的影响会掩盖碱度带来的差异。Avrami模型和Langmuir模型可以较好地拟合生物炭对CO₂的吸附过程,表明CO₂在生物炭上的吸附以单层吸附为主。生物炭吸附CO₂是以物理吸附为主伴有化学吸附作用的过程,且受温度影响较大,当温度从0℃升高到65℃时,生物炭对CO₂的...     

掺杂改性锂基材料吸附CO2的研究进展

锂基吸附剂因稳定性强、理论吸附量大、吸附温度较高等优点,成为近年来捕获烟道气中CO₂的研究热点。主要论述了熔融盐掺杂、金属阳离子掺杂和其他元素掺杂的锂基材料对CO₂的捕获效果,并比较了它们的相关性能,对开发锂基吸附材料的研究和发展方向进行了展望。     

微波辅助合成Ni-gallate(镍基没食子酸金属有机框架)用于CO2吸附的性能研究

CO₂排放导致的一系列环境问题,引起广泛关注,金属有机框架(MOFs)因其超高的孔隙率比表面积,被认为是捕集CO₂的理想材料。采用微波辅助合成Ni-gallate(镍基没食子酸金属有机框架),并借助扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)等表征手段进行分析。结果表明：相较于传统水热合成,微波辅助合成的材料有着较高的结晶度和规则的尺寸形貌,在25℃时表现出更高的CO₂吸附量(3.82mmol/g)。结合微波辅助合成快速高效的优点,通过相转化法和聚酰亚胺复合得到的聚合物材料,不仅具有良好的CO₂吸附性能,而且有着优异的机械和热稳定性,有进一步发展成为工业CO₂捕集材料的潜力。     

MgO/Al2O3吸附剂对CO2静态吸附性能研究

采用等体积浸渍法制备MgO/Al2O3吸附剂。利用X光电子衍射(XRD)、氮气吸附、原位红外吸附等手段对材料的结构进行表征,通过静态吸附的方法对其吸附性能进行了测定。实验结果表明,所得到的MgO/Al2O3吸附剂,主要存在3个不同的碱性位,CO2吸附后主要是以碳酸氢盐、双齿碳酸盐和单齿碳酸盐的形式存在的。当MgO的负载量为10wt%时,其对CO2的吸附量是最大的。在30℃条件下,其对CO2的吸附量为54.1mg/g,随着温度的升高,吸附量有所降低,在100℃时,其对CO2的吸附量为31mg/g,吸附量的降低主要是由于碳酸盐的分解所致。     

石墨烯/金属有机物框架复合材料光催化性能研究

采用还原氧化石墨烯（RGO）和铜基金属有机物框架材料（Cu-BTC）同时对TiO₂进行改性,显著提升其光活性。通过SEM观察复合光催化剂材料的形态,并采用罗丹明-B作为模拟污染物对复合物的可见光催化性能进行估计。进一步通过分析光生电子寿命和电子顺磁共振谱,揭示复合物中RGO和Cu-BTC的作用及光催化机理。最后通过优化各组分的质量分数实现协同作用,在紫外光和可见光照射条件下,罗丹明-B的降解率常数分别达到1.44×10⁻¹和9.2×10⁻² min⁻¹。此外,复合光催化剂具有良好的循环使用稳定性。

     

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。     

金属有机框架材料用于光催化CO2还原的研究进展

CO₂光催化还原转化为有价值的碳氢燃料和化工原料是达成“碳中和”目标的重要途径。金属有机框架材料(MOFs)是一种由有机配位体和金属离子或团簇通过配位键形成的有机-无机杂化材料,具有超高的比表面积、可调的孔结构,并易于功能化修饰,在CO₂光催化还原反应中展现出良好的应用前景。总结了基于MOFs的新型功能材料绿色光催化CO₂还原的最新研究进展,探讨了改性及功能化MOFs材料及MOFs衍生物的光催化CO₂还原反应机理,并从理化特性上分析了材料性能优势的成因。总结了提高光催化还原CO₂反应的活性和选择性的策略。在此基础上,对这类新型催化剂面临的主要问题和未来发展进行了总结与展望。     

MOFs材料吸附存储与分离CO2的研究进展

金属有机框架化合物(Metal Organic Frameworks)是近年来备受关注的材料,因其具有特殊的孔结构且拥有大的比表面积,故在气体吸附、分离,光学材料,磁性材料,催化等领域具有重要的研究价值。介绍了近几年国内外MOFs吸附分离与存储CO2的研究进展。     

单宁改性酚醛基炭气凝胶的制备及其CO2吸附性能

基于绿色低成本的单宁所具有的大量反应性羟基,其与醛类反应具有与苯酚或间苯二酚相似的机制。在传统的酚醛树脂基(苯酚-尿素-甲醛)炭气凝胶的基础上,通过添加单宁进行改性,成功制备出新型高效的CO₂吸附用酚醛基炭气凝胶。通过扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)和氮气吸脱附测试对其表面化学和孔隙结构进行了系统表征,同时通过CO₂吸脱附测试对其CO₂吸附量、选择性吸附及吸附热等进行了研究。结果表明：以绿色可再生的生物质原料单宁对原料进行部分取代,不仅可以显著降低产品成本,还可以明显改善其CO₂的吸附性能。当单宁的添加量(15 g)为苯酚用量的50wt%时,样品具有最大的比表面积(1 376.31 m2·g^-1)和微孔体积(0.55 cm3·g^-1),是一种极具潜力的气体吸附材料。其相应的CO₂吸附量高达5.36 mmol·g^-1,选择性吸附和吸附热则分别为16.84和34.49 kJ·mol^-1<...     

13X@SiO2合成及其甲苯吸附性能

常见的吸附剂如13X等的硅铝比较低,具有较强的亲水性,但水和有机挥发份(VOCs)之间的竞争吸附,常常会影响吸附剂对VOCs实际脱除效果。本研究利用CTABr为模板剂,正硅酸乙酯为硅源,对13X进行表面修饰,制备了以13X为核,介孔硅为壳的核壳复合材料13X@SiO₂,并以甲苯作为探针分子在穿透实验装置对改性前后沸石分别进行干/湿条件下的吸附性能测试。结果表明:在干燥条件下, 13X@SiO₂-2.6样品(制备中添加了2.6 mL正硅酸乙酯)相比13X原样的吸附量提升了18%左右。在30%和50%相对湿度下,13X@SiO₂的最优吸附容量分别提高了约53%和90%;循环再生实验表明13X@SiO₂-2.6样品经2次再生后仍保持初始样品90%的甲苯吸附量。     

High pressure carbon dioxide adsorption on nanoporous carbons prepared by Zeolite Y templating

Nanoporous carbons were synthesized by chemical vapor deposition using furfuryl alcohol/butylene as a carbon source and zeolite Y as a hard template (ZYC). The ZYC were characterized by PXRD, N₂ sorption, and SEM. The carbon materials exhibited predominant microporosity, and the specific surface area increased from 2563 to 3010 m² g⁻¹ as the pyrolysis temperature was raised from 800 to 1000 °C. ZYC prepared at 1000 °C showed a CO₂ adsorption capacity of 986 mg g⁻¹_adsorbent at 40 bar 298 K, which surpasses the capacities of commercial carbons and mesoporous carbon CMK-3, and closely approaches the best performance of the metal organic framework MOF-177. The CO₂ adsorption capacities of the adsorbents were found to be closely correlated with the BET surface areas of the materials tested.     

Chemistry and application of flexible porous coordination polymers

Abstract

Porous coordination polymers (PCPs), which are microporous materials, have been given much attention from both scientific and commercial aspects regarding their application to gas storage, gas separation and catalytic reaction because of the regularity of their pore shape and pore size, accompanied with the functionality. Moreover, in recent years, flexible PCPs, which are structurally transformable depending upon external stimuli, have been attractive because they provide unique properties, dissimilar to those of zeolites. In this review, the chemistry and application of flexible crystalline PCPs are summarized and discussed.     

Chemistry and application of flexible porous coordination polymers

Porous coordination polymers (PCPs), which are microporous materials, have been given much attention from both scientific and commercial aspects regarding their application to gas storage, gas separation and catalytic reaction because of the regularity of their pore shape and pore size, accompanied with the functionality. Moreover, in recent years, flexible PCPs, which are structurally transformable depending upon external stimuli, have been attractive because they provide unique properties, dissimilar to those of zeolites. In this review, the chemistry and application of flexible crystalline PCPs are summarized and discussed.     

含氮多孔炭的制备及其在二氧化碳吸附中的应用

以甲醛(F)和间苯二酚(R)为炭源,赖氨酸为催化剂,采用快速溶胶凝胶法所制含氮多孔炭(RFL)对CO2具有较高的吸附能力;为增加RFL的氮含量,引入适量的三聚氰胺(M),制得的多孔炭(RFLM)含N量增加,比表面积和孔体积也有所增加;在合成体系中进一步引入谷氨酸(G),可使聚合反应速率得到控制,且多孔炭(RFLMG)的织构性质也得到进一步优化。RFLM和RFLMG对CO2的吸附能力较RFL弱,说明多孔炭的含N量与其对CO2的吸附能力没有明确的线性关系,而含氮官能团的存在形式会影响多孔炭对CO2的吸附能力。     

High performance activated carbon for benzene/toluene adsorption from industrial wastewater

A coal-tar-derived mesophase was chemically activated to produce a high surface area (∼3200 m²/g) carbon with a porosity made up of both micropores and mesopores. Its adsorption capacities were found to be among the highest ever reported in literature, reaching values of 860 mg/g and 1200 mg/g for the adsorption of benzene and toluene, respectively, and 1200 mg/g for the combined adsorption of benzene and toluene from an industrial wastewater. Such high values imply that the entire pore system, including the mesopore fraction, is involved in the adsorption process. The almost complete pore filling is thought to be due to the high relative concentrations of the tested solutions, resulting from the low saturation concentration values for benzene and toluene, which were obtained by fitting the adsorption data to the BET equation in liquid phase. The kinetics of adsorption in the batch experiments which were conducted in a syringe-like adsorption chamber was observed to proceed in accordance with the pseudo-second order kinetic model. The combined presence of micropores and mesopores in the material is thought to be the key to the high kinetic performance, which was outstanding in a comparison with other porous materials reported in the literature.     

Enhanced microwave absorption performance of nitrogen-doped porous carbon dodecahedrons composite embedded with ceric dioxide

CeO₂/Co/C dodecahedrons composites with excellent microwave absorption performance were synthesized by using a hydrothermal method. ZIF-67/CeO₂ was first prepared by introducing CeO₂ into the precursor of ZIF-67 and then CeO₂/Co/C composite was obtained after heat treatment. Impedance matching of the samples could be well adjusted by controlling the content of CeO₂. Unique dodecahedral structure for more interfacial reflection and cerium dioxide oxygen vacancies enhance microwave absorption performance. Specifically, the CeO₂/Co/C exhibited a minimum reflection loss of ?68.83 dB is observed at 5.92 GHz, while the thickness was 3.69 mm. The introduction of CeO₂ effectively enhanced the impedance matching of the materials and improved the microwave absorption performance. Therefore, this CeO₂/Co/C composite is a promising microwave absorber material with high performance.     

Recovery of nickel and cobalt from organic acid complexes: adsorption mechanisms of metal-organic complexes onto aminophosphonate chelating resin

This study examined the recovery of nickel and cobalt from organic acid complexes using a chelating aminophosphonate Purolite S950 resin. These metal complexes are generated by bioleaching nickel laterite ores, a commercial nickel and cobalt mineral oxide, with heterotrophic organism and their metabolites or organic acid products. Equilibrium adsorption tests were conducted as a function of Ni and Co concentrations (15-2000 mg/L), solution pH (0.01 and 0.1 M acids) and three metabolic complexing agents (citrate, malate and lactate). It was shown that the adsorption of the various Ni- and Co-complexes on Purolite were quite low, 16-18 and 5.4-9 mg/g of resin, respectively, in comparison to the smaller nickel ions and nickel sulfate. This was attributed to the bulky organic ligands which promoted crowding effect or steric hindrance. The adsorption of these complexes was further hampered by the strong affinity of the resin to H+ ions under acidic conditions. Mechanisms of adsorption, as inferred from the fitted empirical Langmuir and Freundlich models, were correlated to the proposed steric hindrance and competitive adsorption effects. Nickel and cobalt elution from the resin were found be effective and were independent of the type of metal complexes and metal concentrations. This study demonstrated the relative challenges involved in recovering nickel and cobalt from bioleaching solutions.     

Solvo- or hydrothermal fabrication and excellent carbon dioxide adsorption behaviors of magnesium oxides with multiple morphologies and porous structures

MgO nano/microparticles with multiple morphologies and porous structures have been fabricated via the surfactant (poly(N-vinyl-2-pyrrolidone, poly(ethylene glycol) (PEG), cetyltrimethylammonium bromide, oleylamine or triblock copolymer P123 or F127) assisted solvo- or hydrothermal route in a dodecylamine or oleic acid solvent. The as-fabricated MgO samples were characterized by means of numerous techniques. It is shown that the obtained MgO samples were single-phase and of cubic in crystal structure; the particle morphology and pore architecture mainly depended upon the surfactant, solvent, and solvo- or hydrothermal temperature adopted. The solvothermal process resulted in polycrystalline MgO, whereas the hydrothermal one gave rise to single-crystalline MgO. Surface areas (8–169 m² g⁻¹) of the MgO samples derived solvothermally were lower than those (181–204 m² g⁻¹) of the MgO counterparts derived hydrothermally, with the mesoporous MgO generated after the PEG-assisted hydrothermal treatment at 240 °C for 72 h possessing the highest surface area. CO₂ adsorption capacities of the MgO samples were in good agreement with their surface areas, and the mesoporous MgO derived hydrothermally with PEG at 240 °C for 72 h exhibited the largest CO₂ uptake (368 μmol g⁻¹) below 350 °C. We believe that such a high low-temperature adsorption capacity renders the mesoporous magnesia material useful in the utilization of acidic gas adsorption.     

聚苯乙烯基球形活性炭的制备及其对二苯并噻吩的吸附性能

通过水蒸气活化法制备了聚苯乙烯基球形活性炭,并研究了其对二苯并噻吩(DBT)的吸附性能.采用扫描电镜(SEM)、N2吸附、热重分析(TG)以及液相吸附试验考察了球形活性炭的结构特征.结果表明:以苯乙烯离子交换树脂为原料,通过水蒸气活化法,可以得到比表面积979m2/g～1672m2/g的球形活性炭.其中,BET比表面积和孔容随活化时间和水蒸气流量的增加而增大,而孔径小于0.7 nm的窄微孔却减小.球形活性炭对DBT的吸附量可达109.36mg/g,吸附量与比表面积和总孔容关系不大,而与小于0.7nm的窄微孔成正比.球形活性炭在对DBT的吸附过程中存在不可逆吸附.球形活性炭所含窄微孔的孔容越大,脱附所需要的温度越高,不可逆吸附量越大.     

聚乙烯亚胺型吸附纤维的制备及其对二氧化碳的吸附性能

以玻璃纤维作为基质复合聚乙撑亚胺（PEI），制得含多胺基的复合型吸附纤维。表征了该吸附纤维的化学结构，评价了不同PEUEP比例、涂布质量以及吸附气体中CO2浓度对CO2吸附容量的影响。研究表明，在饱和水蒸汽环境中，CO2吸附量随PEUEP比例的增加而增加，对二氧化碳的吸附量最高可达89．11mgCO2／g-吸附纤维，相当于276．96mg CO2／g-PEI，但CO2吸附量随涂布质量的增加而降低。吸附气中CO2含量对CO2吸附容量的影响较大，随吸附气中CO2含量的增加，吸附纤维对CO2的吸附容量也增加。