苯胺在碳纳米管上的吸附特征

苯胺是一种重要的有机化工原料,能通过皮肤和呼吸道进入人体而引起中毒,还会严重污染环境。目前,国内外处理含苯胺废水的方法主要有氧化法、萃取法、生化法、吸附法等。本文使用碳纳米管进行液相吸附除去苯胺。     

高硅分子筛MCM-41热稳定性与水热稳定性的初步研究

高硅分子筛ＭＣＭ－４１热稳定性与水热稳定性的初步研究董维阳,龙英才,郜晓琴,许太明,谢关根,高滋（复旦大学化学系,上海,２００４３３）关键词高硅分子筛ＭＣＭ－４１,热稳定性,水热稳定性,环己烷吸附等温线ＭＣＭ－４１是最近几年刚刚发现的中孔分子筛（Ｍ４...     

活性炭的zeta电位对各种染料吸附的影响3．活性炭对阴离子染料洋红的吸附

测定了在不同pH下活性炭吸附阴离子染料洋红的变化规律,发现活性炭表面的电位(ζ对洋红吸附量的影响起着重要作用.当溶液pH小于活性炭的零电位pH(pHZPC=6.2)时,活性炭表面带正电,它对洋红阴离子具有静电引力,而当pH增大时活性炭的ζ电位下降,静电引力减弱,使得吸附量下降;另一方面由于洋红变色(pH3.5橙色,～pH6.8玫瑰红)后,洋红的溶解度增大,所以导致吸附量很快下降并趋于零.通过活性炭对洋红在不同pH下的吸附动力学和吸附热力学参数的估算,进一步揭示了活性炭在不同pH下对洋红的吸附机理.     

气-液色谱中同系物保留值交点规律的理论探讨

]本文从气-液色谱保留方程出发,从理论和实际两方面研究了气-液色谱中同系物保留值的交点规律,发现：当同系物成员服从碳数规律时,lnVg1/T图有共同交点,此交点位置不但与同系物种类有关,而且与固定相组成有关;当用交点座标预测保留值时,只有选用同一固定相上同一同系物的交点座标,预测结果才是正确可靠的。     

现代涡轮喷气发动机的物理原理

国产C919大飞机实现了中国人的大飞机梦,发动机是大飞机的心脏.以涡轮喷气发动机的产生和发展为载体,在与活塞发动机比较的基础上,分析涡轮喷气发动机的物理原理,探讨了不同类型的发动机对飞机飞行效率的影响,可以增加中学生"物理·技术·社会"的认识.     

自溶液中的吸附 VII: 硅胶自环己烷中吸附醇,酮和酯

The adsorption isotherms of some monofunctional alcohols, ketones and esters from cyclohexane onto silica gel have been determined at 30`C and 10`C. The silica gel used bad a BET area of 417 m2/g and an average pore radius of 45A. The concentrations of free and associated hydroxyls on the silica gel were 1.4 and 4.1/100A^2 respectively. The adsorption order is cyclohexanol>n-octyl alcohol>cyclohexanone>methyl isobutyl ketone>n-propyl acetate=n-amyl acetate. The adsorption decreases with increasing temperature as normal. Except at very low concentrations, the isotherms can be represented by the Langmuir equation. The limiting adsorption, nms, on the silica gel does not accord with the stoichiometric ratio (1:1) between the free surface hydroxyl groups of the adsorbent and the adsorbate. In addition to surface conditions and the functional group of the adsorbate, it seems that the limiting adsorption is also controlled by the other factors, including temperature, solvent, and, sometimes the chain length of the adsorbate. The standard free energy (ΔG0) and standard enthalpy (ΔH0) of the adsorbates in adsorptien processes have been determined from the Langmuir parameters. The results indicate that the absolute value of ΔH0 is higher than that of ΔG0 (in other words, standard entropy ΔS0 is negative), as in the case of the adsorption of gases. Since there is practically no difference in ΔG0 or ΔH0 of adsorption between alcohols or esters, it is suggested that in dilute solution only the polar groups take part in adsorption, and the hydrocarben chains remain in solution during the adsorption process. For ketones, the absolute values of ΔG0 and ΔH0 are somewhat lower for methyl isobutyl ketone than that for cyclohexanone. A possible explanation is that in the adsorbed state the isobutyl chain of the methyl isobutyl ketone may somewhat close to the surface and thus decreases the adsorption and changes the ΔG0 and ΔH0.     

等温捷径的理论和实验

温度是热力学中核心的物理量,也是我们日常生活中最常接触的物理量之一.简单来说,温度是我们对物体冷热程度的度量①.如果我们进一步追溯温度的定义和测量过程,就会接触到另一个我们熟知的重要概念——热平衡.考虑一个如图1(a)所示的带有活塞的气缸,气缸内部封闭一定量的理想气体.我们假设气缸具有导热性,理想气体可以通过气缸与外界...     

氢在A、X及ZSM-5型沸石上的高压物理吸附

The hydrogen adsorption properties and uptake capacities of the A, X and ZSM-5 types of zeolites were investigated at temperatures of 77, 195 and 293 K and pressures up to 7MPa, using a conventional volumetric adsorption apparatus. All hydrogen adsorption isotherms were basically type I, but the maximum in isotherm,a unique feature of supercritical adsorption, was observed at high pressures of 2-5 MPa at 77 K. The isosteric heats of adsorption were determined from the isotherms and the factors that influence their variations were discussed. Different types of zeolites exhibited remarkably different hydrogen uptake, based on both the framework structure and the nature of the cations present. The highest gravimetric storage capacity of 2.55wt% was obtained for NaX-type zeolite at 4 MPa and 77 K. In CaA, NaX and ZSM-5 types of zeolites,hydrogen uptakes were proportional to the specific surface areas, which were associated with the available void volumes of the zeolites. A threshold in hydrogen adsorption observed in NaA and KA was attributed to a pore blocking effect by large cations in KA. A ratio of the kinetic diameter of adsorbate to the effective opening diameter of zeolite was used to judge the blocking effect for physisorption.     

光谱增感染料798的聚集效应与在AgBr上的吸附

用吸收光谱和反射光谱技术研究了黑白片感红染料７９８（３．３’－二羟乙基－５,５’－二甲氧基－９－乙基－噻碳菁氯盐）在甲醇、水及ＫＢｒ水溶液中的聚集效应和吸附于ＡｂＢｒ表面的吸附态性质。其在甲醇中以单分子态存在的最大吸收波长λｍａｘ为５６０ｎｍ。