大孔径多孔碳的初步研究

介绍了氯碱工业用大孔径多孔碳素烧碳管的使用情况和研制实验,并与国外样品进行了性能对比分析。     

多孔陶瓷孔径及其分布测定方法研究进展

孔径及其分布决定了多孔陶瓷的性能及应用,因此对其测定和定量表征非常重要。本文综述了多孔陶瓷孔径及孔径分布的常见测定方法,包括气泡法、压汞法、气体透过法、气体吸附法、气体渗透法、液-液法、悬浮液过滤法、X射线小角度散射法、核磁共振成像法、X射线断层扫描法以及电子显微镜图像分析法。比较了各种测试方法的优缺点,认为电子显微镜图像分析法是最直接有效的测定方法,并对多孔陶瓷的测试表征方法提出了展望。     

混合塑料与改性煤矸石模板制备多孔碳材料及其吸附性能的研究

以塑料为原料、改性煤矸石为模板,在管式炉中用KOH进行活化制备多孔碳材料(PCM)。利用SEM、FT-IR、XRD和氮气吸-脱附对样品的形貌、成分及孔结构进行表征,并以亚甲基蓝(MB)为模拟污染物研究碳材料的吸附性能。结果表明,10 mg PCM在240 min内可使初始质量浓度为100 mg/L的MB几乎完全吸附,吸附量达498. 35 mg/g,降解率达99. 67%。对吸附过程进行拟合后得出,准二级动力学模型可以更好地描述该吸附过程,吸附等温模型符合Langmuir吸附等温模型。     

一种孔径分布能控制的多孔陶瓷

本文介绍了一种主要是通过控制球状二次粒子原料的粒么的工艺方法制备的多孔陶瓷，其孔径分布可以控制在很狭窄的尺寸范围之内。相信这种性质具有很大的潜在使用价值。文章研究了二次粒子粒径变化对孔径分布的影响及有关问题。     

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。     

粉煤灰基质多孔吸附材料的研制

研究了以粉煤灰为基质，以水泥为主要粘结剂制成的多孔吸附材料的工艺参数及其对材料性能的影响，对该材料掺入补加剂后在结构上产生的变化进行了探讨，并阐明了这种材料的一些性能特点和较佳制备工艺参数。     

一种孔径分布能控制的多孔陶瓷

本文介绍了一种主要是通过控制球状二次粒子原料的粒径的工艺方法制备的多孔陶瓷,其孔径分布可以控制在很狭窄的尺寸范围之内。相信这种性质具有很大的潜在使用价值。文章研究了二次粒子粒径变化对孔径分布的影响及有关问题。     

多孔玻璃微珠的研制及其吸附性能研究

对多孔玻璃微珠作为多孔性固体吸附剂的研制及其在液相中的吸附性能作了初步研究，研制出适合于制作多孔玻璃微珠的Na2O-B2O3-SiO2系统玻璃组分，设计了新型的玻璃微珠成珠设备及工艺，利用该组分的玻璃经研磨，成珠、分相、酸溶和膜化等处理方法，制得了直径为1～10μm，孔径约为10nm的多孔玻璃微珠，用氮吸附静态容量法，测得了多孔玻璃微珠的氮吸附等温线、比表面和孔分布曲线，通过多孔玻璃微珠对苯酚、聚氧乙烯醚和聚丙二醇等有机物的吸附实验，给出多孔玻璃微珠对它们的吸附等温线，并指出合理的吸附温度，大的比表面和适当的膜化工艺对提高多孔玻璃微珠的吸附量都是有效的。     

硼碳氮多孔材料的制备及其吸附再生性能研究

硼碳氮(BCN)多孔材料因其具有高的比表面积、优异的化学稳定性而被认为是一种优异的吸附材料。本文以废弃椰壳、硼酸(H₃BO₃)和尿素(CO(NH₂)₂)为原料,采用冷冻干燥法制备多孔生胚,并在NH₃气氛下通过高温固相反应法在不同的反应温度下合成BCN多孔材料。结果表明,随着反应温度的升高,BCN多孔材料孔径逐渐变大,当反应温度为950 ℃时平均孔径为2.1 nm。将BCN多孔材料用于吸附水中孔雀石绿(MG)有机染料,其最大吸附量可达1 239.8 mg·g^-1,5次循环再生后吸附量平均值仍高达1 138.6 mg·g^-1,说明BCN多孔材料具有优异的循环吸附性能。采用Langmuir和Freundlich等温吸附模型、准一级和准二级吸附动力学模型研究了浓度、吸附时间和平衡吸附量之间的关系。结果表明,BCN多孔材料的吸附与准二级吸附动力学模型吻合,其对MG的吸附属于均匀表面单层分子的Langmuir等温吸附。BCN多孔材料展现出优异的吸附能力,是一种非常有应用前景的新型吸附剂。     

基于逾渗理论的多孔过滤介质孔径分布估计方法

结合逾渗理论和网格模型,建立了过滤系数与过滤介质孔径分布的联系方程。利用此方程结合过滤实验数据获得过滤介质孔径分布的统计参数,同时与其他方法获得孔径分布参数以及其他文献中的数据进行比较,并利用计算机模拟过滤过程验证了获得的孔径分布参数,结果表明基于逾渗理论的过滤模型用于孔径分布参数的估计是比较准确和有效的。     

A new analysis method for the determination of the pore size distribution of porous carbons from nitrogen adsorption measurements

A new analysis method has been developed for the determination of the pore size distribution of porous carbons from nitrogen adsorption measurements. The method is based on a molecular model for the adsorption of nitrogen in porous carbon. It allows, for the first time, the distribution of pore sizes to be determined over both the micropore and mesopore size ranges using a single analysis method. In addition to carbons, this method is also applicable to a range of adsorbents, such as silicas and aluminas.     

Using the high pressure methane isotherm for determination of pore size distribution of carbon adsorbents

A method of determining pore size distribution, PSD, of carbon adsorbents based on the high pressure methane isotherm is presented. A generic software package, and an IBM compatible PC, have been used to search for a PSD in the form of a histogram. The method relies on a known local isotherm, in this case, assuming a simplified model of infinite slit shaped carbon pores.Three carbons, having very different pore structures: BPL, PX-21, and PVDC, were analyzed using the new method and the results compared with those obtained from subcritical Ar, and N₂ isotherms. The analysis from the high pressure methane isotherm gave results which are different than those from the low pressure low temperature isotherms but not significantly enough to be unrealistic.     

Relationship between pore fluid velocity distribution and pore size distribution

This study investigated the normalized velocity magnitude distribution and normalized pore volume distribution in different porous media with porosity between 13.5% and 85%, including sandstones, carbonates, synthetic silica, sphere packings and fiber scaffolds. It was found that both velocity magnitude and pore size follow the same distribution. These results allow the prediction of the velocity distribution in a porous medium when its pore structure is known or tuning the velocity by controlling the pore structure.     

Synthesis of micro/meso porous carbon for ultrahigh hydrogen adsorption using cross-linked polyaspartic acid

In addition to the specific surface area, surface topography and characteristics such as the pore size, pore size distribution, and micro/mesopores ratio are factors that determine the performance of porous carbons (PCs) in the fields of energy, catalysis, and adsorption. Based on the mechanism of weight loss of polyaspartic acid at high temperatures, this study provided a new method for adjusting the surface morphology of PCs by changing the cross-linking ratio of the precursor, where cross-linked polyaspartic acid was used as precursor without additional activating agents. N₂ adsorption analysis indicated that the specific surface area of the obtained PCs was as high as 1458 m²·g^–1, of which 1200 m²·g^–1 was the contribution of the microporous area and the highest pore volume was 1.13 cm³·g^–1, of which the micropore volume was 0.636 cm³·g^–1. The thermogravimetric analysis results of the precursor, and also the scanning electron microscopy and Brunauer–Emmet–Teller analysis results of the carbonization product confirmed that the prepared PCs presented multilevel pore structure, and the diameters of most pores were 0.78 and 3.97 nm; moreover, the pore size distribution was relatively uniform. This conferred the PCs the ultrahigh hydrogen adsorption capacity of up to 4.52 wt-% at 77 K and 1.13 bar, in addition to their great energy storage and catalytic potential.     

基于阻滞扩散模型估算柴油脱硫吸附剂的适宜孔径分布

通过GC-PFPD色谱分析国Ⅱ、国Ⅲ、国Ⅳ标准0^#柴油中的主要含硫组分,发现苯并噻吩(BT)、二苯并噻吩(DBT)及其烷基取代衍生物是0^#柴油中的主要含硫化合物,C₂-DBT、C₃-DBT是国Ⅳ柴油中的主要含硫化合物。以BT、DBT、4,6-DMDBT为模型化合物,计算含硫化合物在不同大小孔道内的扩散阻滞因子,结合氧化铝堆积孔模型,估算氧化铝基柴油脱硫吸附剂的适宜孔径分布。结果表明,当氧化铝的平均孔径为4～10 nm时,含硫化合物的扩散阻滞因子为0.24～0.65,氧化铝的比表面积为100～250 m²·g^-1,可同时满足较低的扩散阻力和足够大的比表面积。对比分析不同氧化铝的孔分布及其吸附脱硫性能,结果表明氧化铝中4～10 nm范围内的孔面积占总孔面积的百分比与其吸附脱硫性能存在显著的正相关关系,初步推测氧化铝基脱硫吸附剂的适宜孔径分布范围为4～10 nm。     

Effect of alumina fiber content on pore structure and properties of porous ceramics

Porous Al₂O₃ ceramics with different contents of alumina fibers were prepared by gel-casting process. The effects of Al₂O₃ fiber content on pore size distribution, porosity, compressive strength, and load-displacement behavior of the ceramic materials were investigated. Initial results showed that with the increase of Al₂O₃ fiber content, the pore size and porosity of the material is increased, and the compressive strength is decreased. However, upon increasing the fiber content from 50 wt% to 67 wt%, the performance of the samples changed greatly. The compressive strength of the material increased, while the porosity remained unchanged, the pore size increased greatly, and the shape of the load displacement curve changed. It showed that when the fiber content increased from 50 wt% to 67 wt%, the loading body in the fiber-reinforced porous ceramics changed from particles to fibers.     

岩沥青基多孔碳的制备及其吸附性能研究

采用溶剂萃取法净化天然岩沥青矿,得到岩沥青样品。研究溶剂对天然岩沥青萃取率的影响,当石油醚与二甲苯的质量比为1∶9时,其萃取率高达82.15%。以净化后的岩沥青为原料制备多孔碳,采用SEM、TEM和BET等方法对材料进行表征,探究助剂脒基硫脲(AU)和硫酸铵(AS)对多孔碳(PC)形貌和结构的影响。BET分析结果表明:AU/PC和AS/PC的比表面积分别为56 m^(2)/g和466 m^(2)/g,总孔容分别为0.113 cm^(3)/g和0.365 cm^(3)/g,AS/PC的孔径主要分布在1.7~3.0 nm,具有丰富的孔隙结构。同时探究了岩沥青基多孔碳材料对水溶液中Cd(Ⅱ)的吸附性能。     

活性炭孔径分布对乙炔氢氯化低固汞催化剂性能的影响

以煤粉为碳源,加入磷酸氢二钠、磷酸二氢钾为辅助剂,通过水蒸气活化的方法制备了具有不同孔径结构分布的活性炭载体。利用氮气吸脱附曲线、亚甲基蓝吸附曲线、X射线衍射（XRD）及扫描电子显微镜（SEM）分析技术对活性炭载体和催化剂进行表征。在等温固定床反应器中模拟实际生产转换器单管装置,考察了不同孔径分布的载体对催化剂催化性能的影响。结果表明：调节不同的磷酸氢二钠、磷酸二氢钾配比量和活化蒸汽量,可以制得不同比表面积和孔径分布活性炭载体,中孔率可达81%;高中孔含量的催化剂载体有利于活性中心的分散,且由其制备的催化剂在高空速下活性稳定性更好,寿命更长。