超临界二氧化碳中聚氨酯吸附小分子的影响因素

研究了超临界CO2 中降压时间以及小分子的溶度参数、亲电性和芳香性等因素对聚氨酯吸附小分子的影响,考察了小分子比蒸发速率对小分子在聚氨酯中解吸的影响.结果表明聚氨酯易于吸附亲电性试剂和多数芳香族小分子.通常比蒸发速率大的小分子在聚氨酯中解吸也快     

超临界二氧化碳中聚氨酯吸附小分子的影响因素

研究了超临界ＣＯ２中降压时间以及小分子的溶度参数、亲电性和芳香性等因素对聚氨酯吸附小分子的影响,考察了小分子比蒸发速率对小分子在聚氨酯中解吸的影响。结果表明聚氨酯易于吸附亲电性试剂和多数芳香剂族小分子,通常比蒸发速率大的小分子在聚氨酯中解吸也快。     

超临界二氧化碳中不同聚合物吸附小分子的比较

研究了超临界二氧化碳中聚氨酯,乙烯醋酸乙烯共聚物和低密度聚乙烯等3种聚合物对几种小分子的吸附作用,观测了吸附小分子后的聚合物的形态变化以及无水乙醇和乙酸乙酯在这3种聚合物中的解吸,实验表明低密度聚乙烯吸附能力较差,不适作吸附的基体材料,而聚氨酯,乙烯醋酸乙烯共聚物吸附小分子能力较强。小分子在聚合物中按时间的自然指数形式递减规律解吸,解吸扩散系数数量级达10-7cm2/s。     

二氧化碳从它溶胀后的聚合物中的解吸

研究了经过40℃,8.0～14.0MPa的超临界二氧化碳溶胀后的6种聚合物LDPE、PP、PA6、EVA、PS和PU中的CO2解吸情况,模拟了聚合物中CO2的解吸规律,即以时间的自然指数递减规律,并根据Fick扩散定理从理论上推导出CO2在聚合物中的解吸方程,由解吸方程计算解吸扩散系数,结果表明CO2的解吸扩散系数数量级达10-7cm2/s,解吸扩散系数与CO2在聚合物中的浓度和温度以及解吸前聚合物在超临界二氧化碳中的压力有关。     

Monte Carlo法模拟CO在Fe(100)表面的升温脱附

以类桥位的模型为基础,采用MonteCarlo算法,结合键级守恒-Morse势方法(BOC-MP),模拟了CO在Fe(100)表面上平躺式吸附,考虑了金属与吸附质(M-A)、吸附质与吸附质(A-A)之间的相互作用,以研究小分子在金属表面上的TPD谱图,分析了CO的解离过程和脱附过程对TPD谱图的影响,结果表明,理论模拟与实验相符.     

超临界二氧化碳中聚氨酯对小分子的吸附作用

研究了超临界ＣＯ２中聚氨酯对乙醇、麝香草酚和β－苯乙醇等小分子的吸附作用,观测了超临界ＣＯ２的温度、压力、吸附时间和聚氨酯厚度对小分子吸附量的影响以及小分子在聚氨酯中的释放规律,并探讨了小分子的渗透机理。     

甲基对硫磷和西维因在粘土矿物表面的吸附解吸特性

研究了甲基对硫磷和西维因在蒙脱石、高岭石和针铁矿表面的吸附 解吸特征。结果表明,Langmuir方程能较好的描述甲基对硫磷和西维因在３种矿物表面的等温吸附过程,且蒙脱石对农药的最大吸附量大于高岭石和针铁矿。用动力学方程对2种农药的吸附过程进行拟合,Elovich方程、双常数方程和一级动力学方程均得到较好的结果,其中Elovich方程为最佳模型,相关系数（R²）在0.93～0.98之间,说明该吸附为非均相扩散过程。3种矿物对甲基对硫磷和西维因的吸附强度均为蒙脱石＞高岭石＞针铁矿。     

CaO高温吸附捕集CO2-制备CaO的钙基前驱体材料筛选

价格低廉的CaO材料在高温下能高效吸附捕集CO2气体,被认为是碳减排的有效方法之一．然而,CaO长时间循环碳酸化／煅烧解吸后,其CO2的化学吸附容量下降,稳定性较差,限制了该材料的工业应用．本文采用天然钙源（牡蛎壳和方解石等）和化学试剂（醋酸钙）为钙基前驱材料制备CaO．采用扫描电子显微镜（SEM）,X射线衍射仪（XRD）和氮气吸附仪等手段对制备的CaO材料进行形貌和物理结构的分析表征;在高温和模拟的烟道气氛条件下（10％C02和90％N2）,采用热重分析仪测量CaO吸附CO2的能力和长时间循环碳酸化／煅烧解吸后的稳定性．我们经过与目前所报道的其他钙基吸附材料进行比较,并结合钙基前驱材料的市场价格,发现CaO（醋酸钙）的CO2吸附能力和稳定性较为理想,醋酸钙在高温烟气捕碳方面具有非常好的应用前景．     

绿茶对水溶液中Pb2+和Cd2+吸附性能初步研究

研究了绿茶对溶液中Pb2 和Cd2 离子的吸附和解吸性质。考察了pH、温度、吸附时间对绿茶吸附性能的影响,得到吸附动力学曲线和吸附等温线。结果表明,茶叶在pH为4~6的弱酸性范围内对两种金属离子的吸附效果最佳,在30℃时,茶叶对Pb2 和Cd2 的饱和吸附量分别为46.66 mg/g和33.29mg/g,吸附符合Langmuir吸附等温方程,并对吸附机理进行了初步的探讨。对解吸条件研究发现,用0.1 mol/L HCl和EDTA作为解吸剂,对Pb2 和Cd2 的解吸效果较好,解吸率达80%以上,可有效回收重金属Pb2 和Cd2 。     

菜园土壤镉吸附-解吸特性的研究

研究了菜园土壤的吸附－解吸特性,结果表明,等温条件下三种菜园土壤对Cd^2 的吸附量与平衡液中Cd^2 浓度的关系均可用Langmuir方程和Freundlich方程来描述,相关系数均达到0．98以上,达极显著水平,由Langmuir方程求得的菜园土壤对Cd2 的最大吸附量和最大缓冲容量的顺序为：黄松土＞粉泥土＞江涂砂;由Freundlich方程得到的三种菜园土壤对Cd2 的吸附作用力强度以黄松土为最小,粉泥土和江涂砂无明显差别,菜园土壤吸附的Cd2 的解吸量与吸附量呈极显著正相关,但有相当大部分吸附的镉不能被解吸,而仍被土壤所固特。     

SC-CO2中聚氨酯吸附樟脑的研究

研究了在SC－CO2中不同聚合物对樟脑的吸附,发现聚氨酯、乙烯－醋酸乙烯酯共聚物等非晶型和高分子的吸附效果优于聚乙烯等结晶型高分子。继而以聚氨酯为对象,分别讨论了实验温度、压力、吸附时间和不同共溶剂分子对其吸附结果的影响,结果表明,实验温度越高,吸附时间越长,则聚氨酯对樟脑的吸附量越大。当吸附时间相同,吸附量随压力增先增后减,在临界压附近会出现一级大值,在共溶剂的使用中,醇类分子比酮类和胺类分子能更大地提高聚氨酯的对樟脑的吸附量。     

An experimental and molecular simulation study of the adsorption of carbon dioxide and methane in nanoporous carbons in the presence of water

The adsorption of carbon dioxide and methane in nanoporous carbons in the presence of water is studied using experiments and molecular simulations. For all amounts of adsorbed water molecules, the adsorption isotherms for carbon dioxide and methane resemble those obtained for pure fluids. The pore filling mechanism does not seem to be affected by the presence of the water molecules. Moreover, the pressure at which the maximum adsorbed amount of methane or carbon dioxide is reached is nearly insensitive to the loading of preadsorbed water molecules. In contrast, the adsorbed amount of methane or carbon dioxide decreases linearly with the number of guest water molecules. Typical molecular configurations obtained using molecular simulation indicate that the water molecules form isolated clusters within the host porous carbon due to the nonfavorable interaction between carbon dioxide or methane and water.     

Spectroscopic identification of the mixed hydrogen and carbon dioxide clathrate hydrate

In this contribution, we first found the novel clathrate hydrate containing two gaseous guests of hydrogen and carbon dioxide by spectroscopic analysis. X-ray powder diffraction and NMR spectroscopy were used to identify structure and guest distribution of the mixed H2 + CO2 hydrate. X-ray diffraction result confirmed that the unit cell parameter was 11.8602 +/- 0.0010 A, and the formed hydrate was identified as structure I hydrate. 1H magic angle spinning (MAS) NMR and 13C cross-polarization (CP) NMR spectroscopy were used to examine the distribution of hydrogen and carbon dioxide molecules in the cages of structure I, respectively. These NMR spectra showed that carbon dioxide molecules occupied both small 512 cages and large 51262 cages, and hydrogen molecules only were occluded in small 512 cages of structure I. The new finding of the mixed hydrogen hydrate is expected to contribute toward the development of hydrogen production technology and, particularly, inclusion chemistry.     

Liquid carbon dioxide as a solvent for the radiation polymerization of ethylene

The usefulness of liquid carbon dioxide as a solvent for polymerization of ethylene was studied. The effect of liquid carbon dioxide on the polymerization was investigated under conditions of the pressure of 400 kg./cm.² over the temperature range 20–45°C. by using γ-radiation and AIBN as initiators. The infrared spectrum of the polymers showed that carbon dioxide had little effect on the polymer structure. The polymers contained no combined carbon dioxide and only small amounts of vinylidene unsaturation. The methyl content of the polymers was 0.5–4.0 CH₃/1000C. The polymer yield and molecular weight were found to be decreased by the addition of carbon dioxide in both polymerization by γ-radiation and AIBN. The number of polymer molecules formed per unit time increased with the content of carbon dioxide in the γ-ray polymerization, and was constant in the case of AIBN. The advantages of the use of liquid carbon dioxide as a solvent in this polymerization were also considered from the viewpoints of the continuous process, the separation of polymer, the stability of carbon dioxide to radiation, and commercial applications.     

Impact of carbon dioxide on the surface tension of 1-hexanol aqueous solutions

Effects of carbon dioxide presence on the surface tension and adsorption kinetics of 1-hexanol solutions were investigated. Experiments were performed at a range of carbon dioxide vapor pressures and varying concentrations of 1-hexanol aqueous solution. Both dynamic and steady-state surface tensions of 1-hexanol aqueous solution were found to decrease with carbon dioxide pressure, and a linear relationship was observed between the steady-state surface tension and carbon dioxide pressure. To explain the experiments, adsorption and desorption of the two species (1-hexanol and carbon dioxide) from two sides of the vapor-liquid interface were considered. A modified Langmuir isotherm, the modified Langmuir equation of state and the modified kinetic transfer equation were developed. The resulting steady-state and dynamic surface tension data were modeled using the modified Langmuir equation of state and the modified kinetic transfer equation, respectively. Equilibrium constants and adsorption rate constants of 1-hexanol and carbon dioxide were evaluated through a minimization procedure for CO₂ pressures ranging from 0 to 690 kPa. From the steady-state modeling, the equilibrium parameters for 1-hexanol and carbon dioxide adsorption from vapor phase and liquid phase were found unchanged at different pressures of carbon dioxide. From the dynamic modeling, the adsorption rate constants for 1-hexanol and carbon dioxide from vapor phase and liquid phase were found to decrease with carbon dioxide pressure. Some fluctuations in the fitting parameters of the dynamic modeling (adsorption rate constants) were observed. These fluctuations may be due to experimental errors, or more likely the limitations of the model used. A major limitation of the model is related to large differences in adsorption/desorption between initial and final stages of the process, and a single set of property parameters cannot describe both initial and final states of the system. Variations may occur depending on which set of data, of initial or final states, is used in the model predictions over the entire time range.     

High pressure phase equilibrium for δ-tocopherol + CO2

Vapour–liquid equilibrium compositions were measured for mixtures of δ-tocopherol and carbon dioxide, at pressures from 9 up to 27 MPa, and four temperatures between 306 and 333 K. The system exhibits liquid–liquid equilibrium at high pressures, similarly to previous results for mixtures of α-tocopherol with carbon dioxide. The results were correlated with the Peng–Robinson equation of state, using the Panagiotopoulos–Reid combination rules.Comparison of the solubilities of δ-tocopherol and α-tocopherol in supercritical carbon dioxide was performed using Chrastil’s equation to correlate the data. The number of solvent CO₂ molecules per solute molecule was calculated in both cases. An enthalpy of solvation per mole of CO₂ of −10 kJ mol⁻¹ was obtained.