PAN基活性炭纤维的氮吸附

通过对不同活化方法制备相同原料聚丙烯腈基活性炭纤维进行氮吸附研究,结果表明由不同活化方法所制备的活性炭纤维的孔结构存在较大差异,并对随着活化程度的改变其孔结构的发展进行了研究.结果表明通过简单的改变活化方法即可以制得不同孔隙占主导地位的的炭质吸附剂,由此也预示着对于不同的活化方法其活化机理的差别.     

用LA催化预处理粘胶纤维的炭化活化过程研究

粘胶纤维毡由化学药品ＬＡ催化预处理，然后经高温８２０～８５０℃下水蒸汽活化来制备粘胶活性炭纤维，其孔结构受热解炭化和活化过程的影响。本文研究了不同升温速率、不同温度下通入水蒸汽以及不同空速对活化结果的影响；同时考察了粘胶炭纤维与水蒸汽反应的动力学以及粘胶活性炭纤维的吸附性能。     

纤维氧化铝的孔结构特征

本文系统地研究了不同类型纤维Al_2O_3孔结构特征,并对不同孔结构的纤维Al_2O_3-Pt催化剂作了环己烷脱氢性能考察。试验结果表明,将普通的纤维Al_2O_3在900℃以下活化为含微孔的中孔物质,改变制备方法可获得高表面积、高活性的纤维Al_2O_3,或者基本上为微孔结构的纤维。所以,可以通过不同手段获得不同结构的纤维Al_3O_3,以适应各种不同的用途。     

浸渍金属盐二次活化制备中孔沥青基球形活性炭的研究

以煤焦油沥青为原料,水蒸气活化法制备具有一定孔隙结构的预活化沥青基球形活性炭:通过在预活化球形活性炭中浸渍Fe(NO3)3、Co(NO3)2、Ni(NO3)2水蒸气二次活化,制备得到具有不同中孔孔径分布和较高强度的球形活性炭;研究了金属Fe、CO、Ni在二次活化过程中对预活化球形活性炭的孔结构参数和VB12吸附性能的影响,实验结果表明,预活化球形活性炭通过浸渍硝酸盐二次活化能够有效提高中孔孔容和中孔含量,其中浸渍CO(NO3)2二次活化对中孔孔容的增加最为明显,其中孔孔容达0.50cm3/g,占总孔孔容的65%.随着浸溃Co(NO3)2二次活化时间的延长,预活化球形活性炭中孔孔容增加,孔径分布变宽.     

多微孔活性炭的制备及对二甲苯的吸附研究

研究了以木质活性炭颗粒为原料,通过KOH再活化的方法制备多微孔活性炭的方法。考察了活性炭和KOH的最佳质量比例,并通过低温氮吸附、SEM、XRD等手段表征了样品的比表面、孔结构、孔分布、颗粒形貌和晶体结构;通过对含间二甲苯50mg.L-1的气流的吸附实验表征了所制备活性炭的二甲苯去除能力,实验结果表明,经过KOH再活化显著调高了样品的间二甲苯吸附容量,这很可能和样品中发达的微孔结构有关。     

活性炭纤维对铂离子的还原吸附特征

利用不同的活化工艺,制备了水蒸汽活化和磷酸或氯化锌活化活性炭纤维,并借助扫描电镜(SEM)、X-射线衍射(XRD)和光电子能谱(XPS)等技术,研究了这些活性炭纤维对铂的还原吸附特征。结果表明,各活性炭纤维均能还原吸附铂离子,吸附容量为30mgPt/gC至90mgPt/gC之间。依据活性炭纤维种类的不同,还原吸附的铂呈粒状或放射性簇状存在于活性炭纤维表面,铂颗粒的粒径为几十nm至1μm之间。对纤维表面铂的XRD分析表明,还原吸附的铂呈无定型结构,但经过400℃高温处理后,颗粒转化为金属铂结晶形态。还原吸附铂后,活性炭纤维表面的含氧基团相应增加,显示其表面被氧化为羟基和羰基。     

活性碳纤维的结构修饰及其吸附氙性能的研究

活性炭纤维对氙的吸附容量与其孔结构密切相关，为了提高活性炭纤维对氙气的吸附容量，本文分别用亚甲基蓝、对硝基苯酚等有机物，或氯化钠、碘等无机化合物填充的方法修饰活性炭纤维的孔结构；以及利用高锰酸钾或硝酸等氧化处理修饰活性炭纤维的表面化学性质，同时，利用低温氮等温吸附表征了这些改性活性炭纤维的孔结构，以及通过光电子能谱表征了改性活性炭纤维的表面化学结构，上述化合物充填或氧化改性活性炭纤维对氙的吸附性能的研究结果表明，适量化合物填充，或合适浓度硝酸对活性炭纤维的表面处理，可以有效地修饰活性炭纤维的孔结构或改变活性炭纤维表面对氙的亲和力。因而可有效地提高改性活性炭纤维对氙的吸附容量。     

多微孔活性炭的制备及对二甲苯的吸附研究

研究了以木质活性炭颗粒为原料, 通过KOH再活化的方法制备多微孔活性炭的方法。考察了活性炭和KOH的最佳质量比例, 并通过低温氮吸附、SEM、XRD等手段表征了样品的比表面、孔结构、孔分布、颗粒形貌和晶体结构;通过对含间二甲苯50 mg·L^-1的气流的吸附实验表征了所制备活性炭的二甲苯去除能力, 实验结果表明, 经过KOH再活化显著调高了样品的间二甲苯吸附容量, 这很可能和样品中发达的微孔结构有关。     

水蒸气活化制备烟杆基颗粒活性炭的研究

以烟杆废弃物为原料,以木焦油为主的复合粘结剂,通过水蒸气活化制备了烟杆基颗粒活性炭.对影响颗粒活性炭吸附性能和收率的因素如活化温度、活化时间、水蒸气流量进行了系统研究,得到了最佳工艺条件:活化温度为900℃,活化时间为60 min,水蒸气流量为3.31 g/min.该工艺条件下,烟杆基颗粒活性炭对碘的吸附值为1028 mg/g,对亚甲基蓝的吸附值为285 mg/g,收率为24.39%.同时,测定了该活性炭氮吸附,通过BET计算了活性炭的比表面积,并通过密度函数理论(DFT)表征了活性炭的孔结构.结果表明,该活性炭为微孔型,BET比表面积为1073 m2/g,总孔容为0.8152 ml/g.     

KOH活化糠醛渣制备活性炭机理与表征

以糠醛渣为原料、KOH为活化剂,采用两步活化法制备了活性炭。考察了活化温度、活化时间、碱炭比和浸渍时间对活性炭孔结构及吸附性能的影响。采用低温N2吸附、BET、BJH及DFT理论对活性炭孔结构进行了表征分析,利用傅里叶变换红外-拉曼光谱仪检测其表面官能团,分别使用扫描电镜和X射线衍射对其进行表观形貌观察和晶型分析。结果表明,制备活性炭的最佳工艺条件为:活化温度800℃、活化时间3h、碱炭比3∶1、浸渍时间12h。所制备的糠醛渣活性炭的吸附孔径分布集中,吸附孔容为0.8825cm2/g,DFT总比表面积为3290.5m2/g,其碘吸附值和亚甲基蓝吸附值分别为2107.32mg/g和39.67mL/0.1g。     

CsxH3-xPW12O40的孔结构

Ｎ２静态吸附容量法的测定结果表明，磷钨酸铯盐（ＣｓｘＨ３－ｘＰＷ１２Ｏ４０）的孔窝和孔分布与ｘ值的大小相关。ｘ〈１．５的ＣｓｘＨ３－ｘＰＷ１２Ｏ４０孔容相近，孔分布近似；当ｘ〉１．５时，ＣｓｘＨ３－ｘＰＷ１２Ｏ４０的孔主要是孔径小于１０ｎｍ的中孔和微孔，平均孔径及孔容随ｘ的增加而增大。ＳＥＭ和ＴＥＭ的观测结果表明，ＣｓｘＨ３－ｘＰＷ１２Ｏ４０的孔是微细粒子堆积留下的空隙孔，可能不存在晶内孔。     

Modelling of the pore structure variation with pH for pore-filled pH-sensitive poly(vinylidene fluoride)–poly(acrylic acid) membranes

Pore structure variation as a function of pH was investigated for the pore-filled pH-sensitive poly(acrylic acid)-poly(vinylidene fluoride) membranes. The pore radius reduced drastically as the poly(acrylic acid) gel incorporated inside the nascent substrate, which is from 113 nm of nascent substrate to as low as 7.0 nm of pore-filled membranes at pH acidic. For the membranes, the pore radii at pH neutral estimated by the extend Nernst–Planck equation (2.76–4.20 nm) and by the Spiegler–Kedem model with the steric-hindrance pore model (3.4–4.1 nm) are close to each other and comparable with that calculated from the poly(acrylic acid) gel correlation length (1.79–2.93 nm). The calculated pore density at pH neutral (49–258 × 10¹⁴ m⁻²) is much higher than that at pH acidic (2.8–39.8 × 10¹⁴ m⁻²). The results are interpreted in terms of the gel structure in the pore-filled membranes.     

几种植物基活性炭材料的孔结构与吸附性能比较——(I)孔结构表征

测定了3种植物基活性炭材料:椰壳活性炭 (CAC4)、剑麻茎基活性炭 (SSAC) 和剑麻基活性碳纤维 (SACF) 的氮吸附等温线,并用不同的理论方法对其孔结构进行了分析和表征。结果表明:CAC4为微孔型,孔径分布集中且大部分是0.7nm以下的极微孔;在相同条件下制备的SSAC和SACF孔分布较为相似,都呈多分散性,结构中除微孔外,还含有丰富的中孔,中孔率均超过50%以上。两者相比,SACF的中孔量和平均孔径更大。3个样品的形态特征和孔结构虽然不同,但其吸附过程都可以用微孔多段填充机理来解析。     

Permeability of hydrophilic and hydrophobic Shirasu-porous-glass (SPG) membranes to pure liquids and its microstructure

Morphological properties of hydrophilic and hydrophobic Shirasu-porous-glass (SPG) membranes were investigated over a wide range of mean pore sizes (0.252–20.3 μm) by liquid permeability measurements, scanning electron microscopy and Hg porosimetry. Hydrophobic modification of membrane surface was made by surface coating with silicone resin. The results are discussed using the non-uniform capillary bundle model of membrane permeability. The mean pore tortuosity of 1.28 was kept constant over the whole range of mean pore sizes investigated. The SEM images confirmed that the geometry of pore network was similar for all SPG membranes, irrespective of their mean pore size. The span of pore size distribution ranged from 0.28 to 0.68 and the number of pores per unit cross-sectional membrane area from 10⁹ to 10¹³ m⁻². The membrane resistance was unchanged after surface treatment with silicone resin, which means that the pores were not plugged by the resin, even in the submicron range of mean pore sizes.     

In situ physical or covalent trapping of phthalocyanine macrocycles within porous silica networks

An effective way of trapping phthalocyanines inside porous silica has been achieved when an aqueous solution of these macrocyclic species is reacted in situ with silicon alkoxide. The resultant porous gel network can encapsulate a myriad of metal phthalocyanine molecules at relatively high concentrations and, most importantly, in a disaggregated way. By employing this method metal sulfophthalocyanines of Fe, Co, Ni, Cu, Al, Eu or Sm can be encapsulated within SiO₂ xerogels. Here, the chemical entrapment of phthalocyanines inside silica gel pore networks is accomplished by the attachment of bifunctional groups to the walls of these substrates; while one of these moieties is directly linked to the macrocycle end groups, the other one is covalently bonded to the silanol groups resting on the SiO₂ walls. Furthermore, when the proper concentrations of phthalocyanine species, H₂O, silicon alkoxide, and HCl are reacted together, it is possible to obtain monolithic translucent silica xerogels. This latter property provides straightforward evidence of the innate fluorescence of the trapped macrocycles. The average size of the cavities encapsulating the macrocyclic molecules range from 2.0 to 3.6 nm; the precise size depends on the cation present in the complex and on the identity and position of the substituent groups at the periphery of the macrocycle. When the silica network is prepared from standard and/or organo-substituted alkoxides, the aggregation, degradation or stability of the macrocyclic species trapped in silica cavities depends on the nature of the alkyl group attached to the pore walls.     

Peptide pore accessibility in reversed-phase chromatography

The effect of salt or peptide concentration on peptide porosity (i.e. the porosity accessible to a given peptide) is investigated on six different reversed-phase stationary phases. The peptide porosity is found to increase with the local concentration of negative charges following a saturation-type function within the same porosity boundaries for both cases. This can induce the formation of anti-Langmuirian peaks in non-adsorbing conditions since the local increase of the ionic strength due to the peptide concentration increases the porosity accessible to the peptide. This behavior can be well reproduced by the ideal model of chromatography assuming non-constant porosity. The acetonitrile adsorption isotherm was also measured on all the considered reversed-phase stationary phases. A comparison between the stationary phases shows a correlation between the amount of acetonitrile accumulated in the pores and the reduced pore accessibility for the peptide.     

几种新型分子筛吸附性能的研究

在Na_2O-CaO-B_2O_3-Al_2O_3-R-H_2O水热体系中,首次合成了四种新型微孔硼铝酸盐。吸附性能的测定及孔径分布的计算表明,它们均表现有分子筛吸附性能,且其孔径分布集中在0.5～0.7nm之间。     

作为吸附载体用微孔玻璃珠的研制

研制出Na_2O-B_2O_3－Al_2O_3－SiO_2系统玻璃，粉碎成一定粒度的颗粒，制成2mm左右的玻璃珠，经过热处理分相、酸溶、水洗、烘干，得到了气孔率为24％左右的微孔玻璃珠，利用微孔的吸附特性及极大的比表面积，可做为良好的吸附载体材料。     

SYNTHESIS OF MACROPOROUSCOPOLYMER OF VCA AND DVB

1.INTRODUCTIONVinylacetate(VAc)isacommonandcheapmonomeLUsuallyitisusedtopreparelinearhomopolymerorcopolymeLHowever,becauseoftheusefulestergrouppresentinVAc,italsoat'tractsthegreatinterestsofsomescientistswhoworkintheareaoffunctionalpolymers.Recently,alotofreporthaveappearedusingVAcasamainmonomertopreparecrosslinkedpolymersII~sl.ThesereportsmainlyfocustheinterestsonthesynthesisandapplicationoftheVAccontainingcrosslinkedpolymers.Noreportshavebeenfoundtostudythekineticsofthesynthesisofc…     

Porous polystyrene packings: Characterization through pore structure determination

Summary In this paper the pore structure of several porous polystyrene pearls as used in chromatography is investigated by N2-adsorption and by the inverse size exclusion chromatography (SEC) of Halász. The results indicate that only the inverse SEC measurements give valuable information about the polystyrene packing materials although the obtained pore size distribution is too broad. Reasons for the shortcomings of inverse SEC are discussed.