杂多酸的固载化Ⅲ．溶剂对H_4SiW_（12）O_（40）·24H_2O在活性

研究了Ｈ＿４ＳｉＷ＿（１２）Ｏ＿（４０）·２４Ｈ＿２Ｏ（ＳｉＷ＿（１２））在水、乙醇、乙酸、乙酸丁酯中在活性炭上的吸附得出，活性炭微孔结构对ＳｉＷ＿（１２）在其表面的吸附起着分子筛作用。水溶剂化的ＳｉＷ＿（１２）分子可顺利进入活性炭１．７ｎｍ左右的微孔，而其它溶剂化的ＳｉＷ＿（１２）分子，则需较大的孔径。提出了ＳｉＷ＿（１２）在活性炭表面吸附的微孔中孔扩散模型。     

多孔炭物理化学结构及其表征

以碳为基本骨架的多孔炭因具有丰富的孔隙结构和表面化学宫能团,在吸附分离、催化、电子等领域应用广泛.在阐述多孔炭孔结构（物理结构）和表面化学宫能团（化学结构）基础上,重点介绍了透射电镜等可直接观察多孔炭孔结构的表征方法及Dubinin微孔充填理论、平均场密度泛函理论、吸附法、压汞法等表征多孔炭孔结构的主要理论及方法,以及...     

VOCs在吸附剂上吸附性能的热力学研究

采用色谱法与热重(TG)法,测量了正己烷、甲苯和乙酸乙酯在活性炭、5A、NaY、13X、ZSM-5 (SiO_2/Al_2O_3=27、300)、Hβ以及M CM-41等吸附剂上不同温度下的吸脱附行为,并基于反相气相色谱法测得的数据,计算了其吸附热力学参数ΔH、ΔS和ΔG,分析了上述VOCs分子与吸附剂之间的作用机制,并借助FT-IR验证了吸附质在分子筛表面的吸附机制。结果表明,上述吸附过程存在物理吸附和化学吸附两种方式,其中,物理吸附的作用力大小与吸附剂的孔径分布和分子直径相关,而化学吸附的作用力大小依赖于分子筛硅铝比和Ca~(2+)、Na~+、H~+等阳离子及吸附质分子的偶极矩,且强的化学吸附使得部分吸附质分子的脱附温度高于200℃。     

O2、CO2和H2O在UN（001）表面化学吸附的密度泛函理论研究

采用广义梯度近似GGA,修正Perdew—Burke—Ernzerhof交换-关联泛函,以及周期性切片模型对O2、CO2和H2O在UN（001）表面的化学吸附行为进行非白旋极化水平的密度泛函理论计算．在四个对称性化学位置条件下,对化学吸附能与分子和UN（001）表面之间距离的关系曲线进行优化．结果表明O2、CO2和H2O分子的最稳定吸附位置分别为桥式平行、空心平行和桥式H向上,化学吸附能分别为14．127、4．421和5．736kJ／mol．从吸附物UN（001）表面角度考虑,O2与UN（001）表面之间的相互作用最高,然后为CO2和H2O,表明这些相互作用与吸附物的晶体结构相关．O2化学吸附导致UN（001）表面的N原子向基体内部迁移,而CO2和H2O化学吸附对UN（001）表面分别具有中等和忽略不计的效应．计算获得的态密度显示了化学吸附分子S、P轨道和U6d、U5f轨道之间的电子电荷转移行为．     

催化CVD调变PAN-ACF微结构研究

首次采用催化气相沉积法(CVD),以异丙醇为溶剂将催化剂[Ni(NO₃)₂·6H₂O]有效地分散在PAN-ACF较大的微孔上,使其成为积炭的活性位,从而将ACF的孔径调控在分子筛孔径效应范围内.以液氮为吸附质,测定了样品吸附等温线,采用H-K及DFT法计算孔结构,用XRD及SEM表征ACF的显微织构,并对该沉积过程进行了解释.     

硫化钠改性活性炭对Pb(Ⅱ)的吸附性能研究

采用质量分数为3%的Na_2S溶液对活性炭浸渍,在600℃以N_2作为保护气对其进行高温处理,研究Na_2S改性活性炭(SAC)吸附Pb(Ⅱ)的动力学和热力学机理,并对吸附Pb(Ⅱ)前后的改性活性炭进行了表征和分析。结果表明,与改性前活性炭相比,SAC的比表面积和总孔容减小,S元素含量显著提高。SAC对Pb(Ⅱ)的吸附效果显著提高,在Pb(Ⅱ)初始浓度为300mg/L时,SAC对Pb(Ⅱ)最大吸附量为122.56mg/g,并且在吸附过程的前80min内可达到总吸附量的95%以上。SAC对Pb(Ⅱ)的吸附过程可用Langmuir模型描述,动力学特性符合拟二级动力学模型。SAC对Pb(Ⅱ)的吸附的热力学参数ΔG在-80~-20k J/mol之间,ΔH0,ΔS0,表明吸附是自发进行的物理吸附与化学吸附共同作用的放热过程。对吸附前后改性活性炭的傅里叶变换红外谱图分析表明,经过Na_2S改性后,活性炭表面引入了砜基,并且砜基强化了改性活性炭对Pb(Ⅱ)的吸附性能。     

微波再生对活性炭循环吸附SO_2的影响

研究了脱硫活性炭的微波再生及其对烟气中SO2的循环吸附特性。通过扫描电镜、N2吸附、元素分析、Boehm滴定等表征了微波再生对活性炭孔隙结构和表面化学性质的影响,分析了微波再生对活性炭循环吸附烟气中SO2的影响规律。结果表明,微波再生是脱硫活性炭再生的有效手段,在合适的再生功率下,经过多次循环吸附/再生后,活性炭仍然保持较高的吸附容量,吸附17次后再生活性炭仍然高于原始活性炭,但同时由于再生过程中存在C与H2SO4的反应,活性炭存在明显的烧失现象。初次再生后,活性炭的表面酸性官能团在高温下基本完全分解,碱性官能团含量上升,活性炭的SO2吸附容量明显提高;多次吸附/再生循环后,再生反应起到了活化的作用,使活性炭的孔结构变狭长,微孔比表面积和微孔容积呈上升趋势,同时酸性和碱性官能团基本保持稳定,活性炭的SO2吸附容量逐渐增加。     

杂多酸的固载化Ⅲ.溶剂对H4Siw12O40.24H2O在活性炭上吸附的影响

研究了Ｈ４ＳｉＷ１２Ｏ４０．２４Ｈ２Ｏ（ＳｉＷ１２）在水，乙醇，乙酸，乙酸丁酯中在活性炭上的吸附得出，活性炭微孔结构对ＳｉＷ１２在其表面的吸附起着分子筛作用，水溶剂化的ＳｉＷ１２分子可顺利进行活性１．７ｎｍ左右的微孔，而其它溶剂化的ＳｉＷ１２分子，则需较大的孔径，提出了ＳｉＷ１２在活性炭表面吸附的微孔中孔扩散模型。     

活性炭纤维吸附脱除NO过程中NO氧化路径分析

在小型固定床吸附实验台上开展了黏胶基活性炭纤维吸附脱除NO的实验研究。采用H₂O₂溶液浸渍以及热处理方法对活性炭纤维表面进行修饰,以获得表面孔隙结构接近而含氧官能团含量不同的样品;考察样品在惰性氮气气氛、含氧气氛下吸附脱除NO的效果,以及表面含氧含氮官能团的变化规律。探讨了含氧官能团在NO催化氧化过程中的作用及含氧气氛下O₂对于NO转化为NO₂的影响,分析了活性炭纤维表面吸附的NO向NO₂的主要转化途径。结果表明,在氮气气氛下活性炭纤维表面C-O官能团对吸附态的NO起到氧化作用,吸附态NO被C-O官能团氧化生成-NO₂官能团;在含氧气氛下活性炭纤维吸附NO后表面出现-NO₂、-NO₃官能团,通过长时间实验测定三种样品在含氧气氛下对NO吸附的效果,发现三种样品稳定时催化氧化效果一致,表明含氧官能团对初始NO的物理吸附影响较大,而对整个吸附过程影响较小。吸附在活性炭纤维表面上的NO与环境气氛中的游离态O₂发生氧化反应是NO转变为NO₂的主要途径。     

无氧下低浓度硫化氢在浸渍活性炭上的吸附研究

为了考察常温、无氧下浸渍Na2CO3改性、原料气相对湿度对活性炭吸附硫化氢的促进作用,用动态吸附法分别测试了不同湿度下原活性炭和浸渍活性炭对低浓度硫化氢的吸附,同时考察了温度对该吸附过程的影响。结果表明,吸附平衡数据均符合Freundlich吸附等温方程。与原活性炭相比,浸渍活性炭的孔容和比表面积略有降低,但对硫化氢的吸附能力却显著提高,说明硫化氢与浸渍剂在活性炭表面上发生了化学反应。相对湿度增加,活性炭和浸渍活性炭对H2S的吸附能力均显著增强。温度升高,平衡吸附量均略有下降。     

活性炭纤维的微孔结构水吸附

测定了两种活性炭纤维（ACF）的氮气、水吸附等温线和XPS,研究了ACF的微孔结构和表面性质,用αs图分析氮吸附等温线获得了ACF的比表面积、微孔容量和微孔径。XPS表明在ACF表面存在多种不同结合状态的氧。水在ACF上的吸附等温线呈V型,具有很大的脱附滞后环。水通过与ACF表面的氧形成氢键发生吸附。ACF表面的初始吸附点多,则在低、中压时的水吸附量就大。     

Modeling water adsorption in carbon micropores: study of water in carbon molecular sieves

Measurements of water adsorption equilibrium in a carbon molecular sieve are undertaken in order to gain insight into the nature of water adsorption in carbon micropores. The measurements are taken at low concentrations to emphasize the role of oxygen-containing functional groups in the adsorption of water. Comparisons are made with previously published water adsorption data at higher concentrations to provide a data set spanning a wide range of loading. The assembled data set provides an opportunity for comparison of various theories for prediction of water adsorption in carbon micropores. Shortcomings of current theories are outlined, and an analytical theory that is free of these deficiencies is proposed in this investigation. With the consideration of micropore volume and pore size distribution, the experimental data and proposed isotherm model are consistent with previous studies of Takeda carbon molecular sieves. Also investigated is the uptake kinetics of water, which is characterized by a Fickian diffusion mechanism. The Maxwell-Stefan formulation is applied to characterize the dependence of the diffusional mobility upon loading.     

Preparation and performance evaluation of resin-derived carbon spheres for desulfurization of fuels

A polystyrene-based ion-exchange resin was employed as the precursor for preparation of resin-derived carbon spheres(RCSs) through KOH activation with various impregnation ratios.Pore structure,yield and hardness,surface functional groups of the samples and their adsorption performance towards dibenzothiophene(DBT) were investigated.The RCSs with large surface areas(up to 2696m2/g) and total pore volumes(up to 1.46 cm3/g) exhibited larger adsorption capacities than a commercial activated carbon,F400.Polanyi-Dubinin-Mane(PDM) model was applied to fit the adsorption data,which proved that micropore filling was involved during the adsorption process.Moreover,a good linear relationship was observed between the extra-micropore volume and adsorption capacity.Intra-particle diffusion(IPD) model was used to describe the kinetic data of DBT onto the adsorbents.The adsorption processes were divided into three stages according to the different diffusion parameter.The selective adsorption towards DBT in the presence of competing compounds was also investigated and the high selectivity of the RSCs towards DBT may be attributed to the large quantity of acidic oxygen-containing groups.     

Comparative Studies of the Micropore Size Distributions of an Alumina Pillared Montmorillonite and a Molecular Sieve Carbon

The aim of this work is to applicate and to compare various analysis methods for the characterization of the microporous structure from nitrogen adsorption at 77 K of an alumina pillared montmorillonite and a molecular sieve carbon. The adsorption potential distribution (X(A)), the Horvath-Kawazoe (HK) method, the Jaroniec-Gadkare-Choma (JGC) one and a numerical algorithm for the reconstruction of the micropore size distribution (MPSD) from the adsorption equilibrium isotherm have been applied. Comparison of all distributions revealed that the molecular sieve carbon shows smaller micropores and smaller structural hetereogeneity than the alumina pillared montmorillonite.     

Zn-based metal organic framework derivative with uniform metal sites and hierarchical pores for efficient adsorption of formaldehyde

A Zn-containing graphite carbon (Zn-GC) with uniform Zn metal sites and hierarchical pore structure was obtained by pyrolysis of Zn-based metal organic framework (MOF). Zn-GC exhibited excellent adsorption capacity and reproducibility for formaldehyde. The adsorption capacity of Zn-GC was 736 times that of commercial activated carbon and 5.6 times that of ZSM-5 adsorbents. The characterization and experimental results showed that the surface chemical characteristics of the adsorption material play an important role in the adsorption performance. The superior performance was attributed to Zn metal sites and oxygen-containing functional groups on the MOF derivative as well as hierarchical pore structure. The material showed a great potential in the field of organic pollutant removal.     

活性炭孔结构对TiO2/AC复合光催化剂光催化活性的影响

以4种表面化学性质相近, 而孔结构差异较大的活性炭(AC)为原料, 采用酸催化水解法合成了系列TiO2/AC复合催化剂, 考查活性炭孔结构对复合光催化剂活性的影响. 以苯酚为模型物, 考察了催化剂的活性;以低温(77 K)液氮吸附测定活性炭的比表面积、孔容和孔径分布;以Boehm滴定及元素分析定量表征活性炭表面化学性质. 以SEM观测复合催化剂表面TiO2的分散性能;以X射线衍射(XRD)、漫反射光谱(DRS)测试光催化剂晶相结构参数及光吸收阈值. 结果表明, 活性炭孔结构性质对TiO2/AC活性影响显著. AC1、AC2、AC3、AC4对TiO2活性提高的协同系数分别为1.55、2.03、1.28、1.43. 协同系数大小与接触界面面积变化值(⊿S)趋势相似. 具有发达的微孔及适量中孔结构的TiO2/AC复合光催化剂的催化活性最高.     

Structural and sorption properties of carbon replicas obtained by matrix carbonization of organic precursors in SBA-15 and KIT-6

We have carried out a comparative study of matrix carbonization of some organic precursors (sucrose, polydivinylbenzene, polyphenol-formaldehyde, polyacrylonitrile, acetonitrile) in SBA-15 and KIT-6 silica mesoporous molecular sieves. We have shown that carbon mesoporous molecular sieves of the CMK-8 type, obtained in KIT-6 mesopores, have better adsorption characteristics due to the features of the three-dimensional cubic structure, the larger pore volume and thickness of the walls of the framework. The maximum micropore volume is observed in CMK-3 and CMK-8, obtained by carbonization of polyphenol-formaldehyde and polydivinylbenzene, while the greatest specific surface area is observed on carbonization of sucrose, where the maximum hydrogen adsorption capacity is achieved at a level of ∼1.4 wt.% (77 K, 1 atm). We show that the mesopore surface coverage by hydrogen in carbon mesoporous molecular sieves increases as the degree of graphitization increases.     

Influencing the selectivity of zeolite Y for triglycine adsorption

In prior work we studied the adsorption of triglycine on zeolite Y under reference conditions. This study aims to solve the question of which adsorbent properties and process conditions influence the adsorption triglycine from an aqueous solution by zeolite Y. Relevant zeolite parameters to study are: the amount of acidic sites (Si/Al(2) ratio), counter ion, micropore structure. Process conditions that may influence triglycine adsorption are pH, other components such as sugars, amino acids and salts, and temperature. Adsorption of triglycine on zeolite HY is dominated by ionic interaction. The capacity and selectivity of zeolite HY for triglycine can be changed by choosing different Si/Al(2) ratios or changing the counter ion. The presence of cations and basic anions in solutions reduces triglycine adsorption. Fructose and glycine have no significant influence on triglycine adsorption. Temperature only has a slight influence. The pore structure of zeolite Y is not a critical factor for triglycine adsorption, provided pores are accessible to triglycine and in the micropore range (<2 nm). While this allows other zeolites than zeolite Y to be applied, the presence of the supercage structure of zeolite Y is beneficial to obtain better adsorption of triglycine in its neutral form.     

煤焦气化过程中比表面积和孔容积变化规律及其影响因素研究

煤焦的孔隙结构是影响气化反应的重要因素之一，本文通过测定部分气化焦样的比表面积及其孔隙结构，详细地研究了烟煤焦的孔隙结构在气化过程中的变化规律及其影响因素，结果表明，煤焦的孔隙结构在气化过程中的变化不但取决于原煤的性质，而且还取决于气化介质与气化温度；在相同条件下气化至相同气化率时总比表面积和孔体积大小顺序为彬县＞神木＞王封煤焦，总比表面积与微孔比表面积均随温度的升高而降低，在反应的前期CO2与H2O两种气氛下产生的总比表面积与微孔比表面积相当，但在反应后期CO2气氛下能够产生更多的总比表面积与微孔比表面积。     

Hydrogen adsorption in transition metal carbon nano-structures

Templated microporous carbons were synthesized from metal impregnated zeolite Y templates. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were employed to characterize morphology and structure of the generated carbon materials. The surface area, micro- and meso-pore volumes, as well as the pore size distribution of all the carbon materials were determined by N₂ adsorption at 77 K and correlated to their hydrogen storage capacity. All the hydrogen adsorption isotherms were Type 1 and reversible, indicating physisorption at 77 K. Most templated carbons show good hydrogen storage with the best sample Rh-C having surface area 1817 m²/g and micropore volume 1.04 cm³/g, achieving the highest as 8.8 mmol/g hydrogen storage capacity at 77 K, 1 bar. Comparison between activated carbons and synthesized templated carbons revealed that the hydrogen adsorption in the latter carbon samples occurs mainly by pore filling and smaller pores of sizes around 6 Å to 8 Å are filled initially, followed by larger micropores. Overall, hydrogen adsorption was found to be dependent on the micropore volume as well as the pore-size, larger micropore volumes showing higher hydrogen adsorption capacity.