氢在碳纳米材料中吸附的实验研究

按照容积法的原理建立了用于氢气吸附储存研究的吸附等温线测量的实验装置，从实验和理论的角度分析了本实验装置的精度和误差，用实验的方法验证了理想气体状态方程、RK状态方程以及MBWR方程描述实际气体的适用性。本文还测量了经三种不同后处理方式所得到的碳纳米纤维在298K下的吸附等温线，实验结果低于Rzepka的分子模拟计算结果。实验证明，利用MBWR方程描述实际气体和实验结果符合最好，本实验装置适合用于准确确定氢在碳纳米材料中的吸附储存量。     

Adsorption of surfactant during chemical enhanced oil recovery

Surfactant is extensively used as chemicals during chemical enhanced oil recovery (CEOR) process. Effectiveness of surfactant CEOR process depends on several parameters like formation of micro emulsion, ultra-low interfacial tension (IFT) and adsorption of surfactant. First two parameters enhance the effectiveness while the last parameter reduces the effectiveness. Micro emulsions are highly desirable for CEOR due to its low interfacial tension (IFT) value and higher viscosity. In this research the size of the emulsions were studied with particle size analyzer to study the liquid–liquid absorption process and the entrapment of oil drops inside surfactant drop. Initially, the average surfactant drop size was found to be 100 nm, after mixing the surfactant slug with reservoir crude, the size was increase up to 10 times. It signifies the formation of micro emulsion between surfactant and oil. Another attempt was done in this research to study the adsorption mechanism of surfactant on reservoir rock. The process of adsorption was studied by Langmuir and Freundlich isotherm to understand the adsorption phenomena. In this study, it was found that the adsorption follows Freundlich isotherm and the adsorption phenomena was chemical for surfactant flooding process. In chemical adsorption phenomena, the rate of adsorption is high because, surfactant molecules are adsorbed layer after layer by the rock surface. Use of alkali along with surfactant reduces adsorption of surfactant since, alkali blocked the active clay sites before interacting with surfactant and hence the adsorption isotherm was found to be Langmuir and phenomena was physical adsorption.     

Molecular simulation of copper based metal-organic framework (Cu-MOF) for hydrogen adsorption

Metal organic framework (MOF) are widely used in adsorption and separation due to their porous nature, high surface area, structural diversity and lower crystal density. Due to their exceptional thermal and chemical stability, Cu-based MOF are considered excellent hydrogen storage materials in the world of MOFs. Efforts to assess the effectiveness of hydrogen storage in MOFs with molecular simulation and theoretical modeling are crucial in identifying the most promising materials before extensive experiments are undertaken. In the current work, hydrogen adsorption in four copper MOFs namely, MOF-199, MOF 399, PCN-6′, and PCN-20 has been analyzed. These MOFs have a similar secondary building unit (SBU) structure, i.e., twisted boracite (tbo) topology. The Grand Canonical Monte Carlo (GCMC) simulation was carried at room temperature (298 K) as well as at cryogenic temperature (77 K) and pressures ranging from 0 to 1 bar and 0–50 bar. These temperatures and pressure were selected to comply with the conditions set by department of energy (DOE) and to perform a comparative study on hydrogen adsorption at two different temperatures. The adsorption isotherm, isosteric heat, and the adsorption sites were analyzed in all the MOFs. The findings revealed that isosteric heat influenced hydrogen uptake at low pressures, while at high pressures, porosity and surface area affected hydrogen storage capacity. PCN-6′ is considered viable material at 298 K and 77 K due to its high hydrogen uptake.     

色谱固定相吸附性质的测定方法

吸附等温线是描述色谱分离中 ,组分在固定相、流动相两相之间平衡状态的物化参数 ,是色谱分离工艺设计和过程模拟研究中最基本的热力学信息 .准确测定吸附等温线 ,拟合出它的数学模型 ,进而模拟组分在固定相上的吸附和脱附情况 ,可大大减少实验次数 ,迅速找到最佳色谱操作条件 .采用静态法和吸附脱附法 ,测定木糖、木糖醇单、双组分在固定相上的吸附等温线 ,比较测定结果 ,确定吸附脱附法是准确测定等温线的简便方法 .     

不同分子筛对钾离子交换行为的研究

研究了ZSM-5、NaY、USY、13X、SAPO4-34、丝光沸石(mordenite)、4A、β分子筛及斜发沸石(clinoptilolite)对钾离子的交换能力.测定了25℃下NaY等4种分子筛对0.1 mol/L氯化钾溶液的离子交换等温线,利用langmuir模型对等温线进行拟合,得出了不同分子筛对钾离子的饱和交换量.采用NaY等4种分子筛进行了海水中钾离子的交换选择性试验,结果表明,斜发沸石对钾离子选择性最高,对海水中钾离子交换量最大.饱和交换量均较高的13X、NaY分子筛在交换海水中钾离子的同时,也交换了大量钙离子和镁离子,对钾离子的选择性较差.     

醇法大豆浓缩蛋白（SPC）挤压组织化的机理（Ⅰ）──利用反相色谱法研究蛋白质的吸湿过程

本研究开发了一种反相气相色谱法并将其成功地运用于测试蛋白质的吸湿等温线。结果表明：醇法大豆浓缩蛋白的单分子层吸湿量明显低于酸法大豆浓缩蛋白，且在吸湿过程中无溶胀现象。由于蛋白质聚集微粒表面的极性吸附点减少，致使醇法大豆浓缩蛋白无法获得有效的塑化作用。这是该大豆蛋白在常规挤压条件下无法实现组织化的主要原因。     

O,O'-二(2-苯乙基)二硫代磷酸二乙铵在HCl溶液中对Q235钢的缓蚀性研究

合成了一种新型缓蚀剂O,O'-二(2-苯乙基)二硫代磷酸二乙铵(EPP),并用元素分析和红外光谱对其进行了表征。采用静态失重法、极化曲线法和电化学阻抗法研究了EPP在HCl溶液中对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为,考察了HCl浓度、腐蚀体系温度等因素对其缓蚀率的影响。结果表明:EPP是一种高效的混合型缓蚀剂,其缓蚀率随缓蚀剂浓度增加而增大,随腐蚀系统温度升高而缓慢减小。在30℃,1.0 mol·L-1的HCl溶液中,EPP浓度为60 mg·L-1时,其缓蚀率高达98.48%。EPP在Q235钢表面的吸附符合Langmuir吸附等温式,属于自发进行的化学吸附。量子化学计算结果表明,EPP通过配位键和反馈键与金属Fe形成了多中心、稳定的化学吸附。     

高压下页岩吸附特性及吸附异常原因分析

从分子学角度出发,探讨了页岩吸附量随压力变化趋势可能的内在原因。并结合模拟实验数据,分析了页岩在吸附后期出现吸附异常现象的原因。研究认为,甲烷分子在页岩表面的吸附与分子间引斥力的相互作用密切相关。在吸附初期,页岩表面能相对较大,甲烷分子和页岩表面分子间作用力以吸引力为主且逐渐增大,页岩吸附量随压力升高而增大且增加较快;在吸附中期,页岩表面能减小,甲烷分子和页岩表面分子间作用力由吸引力向排斥力转变,页岩吸附量随压力升高增加变缓达到最大值,此时吸附速率与解吸速率动态平衡;在吸附后期的超高压下,页岩表面能趋于零,甲烷分子和页岩表面分子间作用力以排斥力为主且增加较快,页岩吸附量随压力的升高而降低,甚至出现负值。页岩吸附异常的原因主要有两点:一是页岩具有相对低的吸附量,而且甲烷分子直径大于氦气,致使实验所用自由体积值偏大,造成计算结果"负吸附";二是高压下页岩中甲烷处于超临界吸附且具有较大的分子间斥力。     

Effect of measurement parameters on thermodynamic properties of La-based metal hydrides

Pressure–concentration isotherms (PCIs) of LaNi_5−xAl_x (x = 0.3 and 0.4) hydrides were measured using a volumetric method. Two important thermodynamic properties, enthalpy of formation (ΔH) and entropy of formation (ΔS), were calculated using the van't Hoff equation. The effects of the Al content on the hydrogen storage capacity, plateau pressure and thermodynamic properties were studied. Additionally, the effects of the charging/discharging pressure difference (ΔP_s) during each step of the absorption/desorption PCI measurement on the hydrogen storage capacity (wt%), equilibrium pressure (P_e), plateau slope, reaction enthalpy (ΔH) and entropy (ΔS) were studied for LaNi_4.6Al_0.4 hydride. All of these properties (P_e, ΔH, ΔS, etc.) showed a significant variation with ΔP_s. The effect of the temperature range on the estimation of the enthalpy of formation was investigated. It was observed that ΔH depends on the experimental temperature range.     

有机改性蒙脱土对农药敌草隆的吸附研究

以十六烷基三甲基溴化铵(CTAB)有机改性蒙脱土为吸附剂,采用静态摇瓶试验,研究了改性蒙脱土对除草剂敌草隆的吸附行为.探讨了温度、离子强度、腐殖酸、溶液pH值对敌草隆吸附的影响.试验结果表明,CTAB改性蒙脱土对敌草隆具有较大的吸附容量,最大吸附量为20.31 mg/g吸附等温线可用Freundllich方程来描述;吸...