二乙苯溶液中C_8芳烃的吸附平衡

本文以连续流动单管的实验装置,研究了C_8芳烃的单溶质和双溶质在二乙苯溶液中的液相吸附平衡.从测定穿透曲线出发,作出了对二甲苯、邻二甲苯、乙苯、对二甲苯-邻二甲苯等系统在170℃下的吸附等温线.发现当溶质浓度<3.0mo1/1时,吸附等温线符合Henry定津,且双溶质溶液的吸附量可按Radke-Praus Nitz的二维理想稀溶液理论由单溶质吸附等温线进行预测.将Polanyi吸附势理论延伸应用于C_8芳烃的液相吸附.用170℃下pX-DEB系统的吸附平衡数据作出特性曲线,可预测110℃下pX-DEB系统的吸附等温线.并用动态法测定的数据,验证了上述推导.     

活性炭纤维吸附邻硝基苯胺水溶液的研究

采用活性炭纤维(ACF)处理邻硝基苯胺模拟废水,通过静态和动态吸附实验,研究了pH、盐含量、吸附时间对吸附效果的影响,测定了吸附等温线和动态穿透曲线,并进行了ACF再生实验。结果表明,在实验条件下,ACF对邻硝基苯胺的吸附速率很快,5 min去除率达96%,在pH4.4~10.4条件下吸附效果较好,盐的含量对吸附效果影响较小,吸附等温线能用Langmuir和Freundlich方程较好地拟合。溶液流速增大,穿透时间提前,吸附饱和的ACF用无水乙醇再生,重复5次,邻硝基苯胺的回收率均在95%以上,ACF的吸附效率无明显变化。     

大孔强酸型阳离子交换树脂对L-精氨酸的吸附

考察了D001大孔强酸型阳离子交换树脂对L-精氨酸的吸附. 测定了25oC下的吸附等温线,发现用Langmuir方程和Freundlich方程可以较好地描述L-精氨酸在该树脂上的吸附;D001树脂吸附L-精氨酸约30 min即可达到平衡;氯化铵或氯化钠的存在使吸附率明显下降;pH对吸附影响明显,从胱氨酸母液中吸附L-精氨酸的适宜pH为7~8;同时测定了胱氨酸母液吸附的动态吸附穿透曲线和洗脱曲线,穿透曲线较缓而洗脱峰较集中.     

活性炭纤维处理丙烯酸废水的研究

采用活性炭纤维对丙烯酸模拟废水进行静态和动态吸附研究,测定了吸附等温线和动态穿透曲线,并且研究了吸附平衡时间、温度、pH值对处理效果的影响。结果表明,温度升高,吸附效率有所降低;溶液pH在3~4范围内对吸附效率影响不大;吸附时间存在最佳值,最佳吸附时间6 m in。吸附饱和的活性炭纤维用NaOH溶液再生,重复使用3次,吸附效率无明显变化。     

SO_2在活性焦固定床上的吸附性能

在120℃恒温条件下,在活性焦固定床上测定SO2的吸附等温线和动态吸附穿透曲线。采用Langmuir吸附方程拟合,得出饱和吸附量qm=0.072 g/g和Langmuir常数K=0.629 m3/g。根据穿透曲线的形状分析传质机制,建立了吸附过程的数学模型,并用COMSOL Multiphysics软件进行数值求解。模拟结果与试验值吻合良好,表明所建立的模型可用于预测其他条件下的穿透曲线。     

改性分子筛吸附2,2-二甲基丁烷的运行参数研究

M-13X分子筛是13X分子筛经过改性后得到的,具有更好的吸附效果,基于静态吸附试验装置,通过单因素实验得到M-13X吸附2,2-二甲基丁烷时的最佳运行参数为70℃、60%填充率、0.2 MPa、吸附30 min;通过动态吸附,得到了M-13X分子筛的吸附穿透曲线和饱和吸附量;研究通过改变环境温度,得到了M-13X分子筛的吸附等温线。这些研究结果为吸附法处理有机废气的工艺设计提供了参考。     

活性炭纤维处理含酚废水的研究

采用活性炭纤维处理苯酚模拟废水,通过静态和动态吸附研究,测定了吸附等温线动态穿透曲线,并研究了pH、吸附平衡时间对处理效果的影响。结果表明,活性炭纤维对苯酚的吸附容量为275.1mg/g,吸附速率愉,溶液pH＞8时,吸附效率下降;吸附时间存在最佳值。吸附饱和活性炭纤维用10%的氢氧化的钠溶液再生,重复使用3次,吸附效率无明显变化。     

就地CO2泡沫体系的静动态吸附特征研究

研究了体系中起泡剂和稳泡剂的吸附量并通过岩心流动实验,测定了起泡剂和稳泡剂在含油、不含油条件下的滞留量。研究结果表明,稳泡剂的吸附等温线呈“L”型,油砂上的饱和吸附量小于石英砂上的饱和吸附量;起泡剂的吸附等温线呈典型的“S”型,油砂表面上的吸附量总是小于在石英砂表面上的吸附量;稳泡剂和起泡剂的动态吸附量都小于在岩心砂上的静态吸附量,化学剂在含油岩心中的滞留量小于不含油岩心中的滞留量。     

就地CO2泡沫体系的静动态吸附特征研究

研究了体系中起泡剂和稳泡剂的吸附量并通过岩心流动实验,测定了起泡剂和稳泡剂在含油、不含油条件下的滞留量。研究结果表明,稳泡剂的吸附等温线呈"L"型,油砂上的饱和吸附量小于石英砂上的饱和吸附量;起泡剂的吸附等温线呈典型的"S"型,油砂表面上的吸附量总是小于在石英砂表面上的吸附量;稳泡剂和起泡剂的动态吸附量都小于在岩心砂上的静态吸附量,化学剂在含油岩心中的滞留量小于不含油岩心中的滞留量。     

2,4-二氯苯酚在黄土性土壤中的吸附与解吸

采用静态与动态实验相结合的方法,研究了2,4-二氯苯酚在黄土性土壤中的吸附和解吸规律,测定吸附动力学和吸附热力学曲线,获得吸附热力学模型。研究表明,2,4-二氯苯酚在黄土性土壤中吸附等温线可用Freundlich和Langmuir方程描述,其中q0描述饱和吸附量,由Langmuir吸附等温式拟合数据可以看出:TS-2土的饱和吸附量大于TM-1土(这是因为2,4-二氯苯酚在土壤中的吸附量与土壤中有机质的含量密切相关);由Freundlich吸附等温式拟合得到的常数,1/n均1,证明是优惠吸附;根据吸附符合Langmuir方程,说明在土壤表面,2,4-二氯苯酚为单分子层吸附;吸附-解吸具有一定的可逆性,黄土性土壤对2,4-二氯苯酚的吸附能力不强,2,4-二氯苯酚极易穿透土壤,污染地下水。     

Adsorption of tetrahydrothiophene on faujasite type zeolites: Breakthrough curves and FTIR spectroscopy study

Adsorption of tetrahydrothiophene (THT) on NaX, CaX, AgX, and H-USY was studied by dynamic adsorption method and FTIR spectroscopy. The stoichiometric adsorption capacities are not very different for all materials, which is indicative of a complete micropore filling. In contrast, the overall rate constant of adsorption, determined from fitting the breakthrough curves with Bohart–Adams equation, is two times greater for H-USY than for type X zeolites. For NaX, CaX and H-USY, heating under N₂ flow at 300 °C allows to restore completely their initial adsorption capacities. In the case of AgX the same treatment results in a twofold lose of capacity accompanied by a collapse of the zeolite structure as evidenced by XRD. The nature of interaction between THT molecules and zeolites was characterized by FTIR spectroscopy. Only a weak interaction through hydrogen bonding was observed for THT on H-USY leading to an almost complete desorption at 100 °C. For NaX and CaX adsorbed molecules are gradually eliminated when heated to 300 °C while completely different pattern was observed for THT adsorbed on AgX on which the amount of the adsorbate remains nearly constant between 25 and 200 °C, but rapidly decreases on further heating. Such a behavior is indicative of much stronger interaction between THT molecules and Ag⁺ cations in agreement with the data on the regeneration of the adsorbents.     

碳八芳烃异构体分离技术评述

介绍了碳八芳烃异构体工业分离技术的现状、对二甲苯分离技术的新发展。评述了择形催化生产对二甲苯的技术、利用结晶处理高浓度对二甲苯原料、变压吸附低成本浓缩对二甲苯技术、分子筛膜分离对二甲苯等。     

磁性沸石的制备与表征及其对Pb2+的吸附性能

通过氨基甲酸乙酯的粘结作用使天然沸石与Fe3O4结合,制备了具有吸附和磁性能的沸石复合体. 利用XRD, SEM, 氮吸附等温线和振动样品磁强计等对所制磁性沸石进行了表征. 结果表明,与钠型沸石相比,磁性沸石的结构没有发生明显改变,比表面积由25.13 m2/g增至38.01 m2/g. 磁性沸石和钠型沸石对模拟废水中Pb2+的平衡吸附量分别为54.53和66.99 mg/g,两者对Pb2+的吸附符合Langmuir型液相吸附,其单层饱和吸附量分别为50.89和65.92 mg/g.     

Liquid chromatographic separation of xylene isomers on α-cyclodextrin bonded phases

Mesoporous glass beads and silica were modified with α-cyclodextrin (CD) for the separation of xylene isomers by means of direct bonding, linking spacer group, and cross-linking agent. The separation efficiency of the (α-CD modified silica particles was tested by using simple column chromatography. A strong inclusion complex formation of p-xylene was observed from the column packed with α-CD bonded phases. Spacer group and crosslinking agent decreased the formation of the inclusion complex of p-xylene and increased selectivity between m-xylene and o-xylene. The inclusion complex formation of p-xylene was strongly diminished when the mobile phase was switched from methyl alcohol to toluene. The column packed with the cross-linked a-CD bonded silica showed the best performance in the separation of xylene isomers.     

丙烷在不同硅铝比的NanZSM-5型分子筛上的吸附性质的分子模拟

用巨正则系综蒙特卡罗（GCMC）和构型偏倚蒙特卡罗（CBMC）相结合的分子模拟方法,研究了丙烷在不同硅铝比的NanZSM-5型分子筛中的吸附性质,并建立了丙烷在不同硅铝比的NanZSM-5型分子筛上的双点Langmuir等温线模型。计算结果显示,模拟结果与文献报导的实验结果相吻合,分子筛骨架上的硅铝比对丙烷的吸附量和吸附等温线无明显影响,并证实双点Langmuir等温线模型能较好地描述丙烷在不同硅铝比的NanZSM-5型分子筛上的吸附性质。     

Study of Adsorption Equilibrium and Dynamics of Benzene,Toluene, and Xylene on Zeolite NaY

The equilibrium and dynamics of low concentrations of benzene, toluene, and xylene in heptane adsorbed by zeolite NaY at 30, 40, and 50 °C were studied. The Langmuir equation was suggested to simulate the isotherms. Based on isotherms and material balances, multi‐component competitive adsorption isotherms can be successfully predicted by mono‐component adsorption isotherm parameters. A series of column adsorption experiments were conducted to study the adsorption dynamics. The mass transfer equations were solved by numerical analysis and used to describe the breakthrough curves, and the mass transfer coefficients in the adsorption column were obtained as well.     

二甲苯异构体在KY沸石上的低压吸附平衡

用CAHN2000型电子天平在温度303.15～443.15 K、压力3.47～2116.6 Pa条件下测定对二甲苯、间二甲苯、邻二甲苯及甲苯在KY型沸石上的吸附平衡数据.根据Polanyi吸附势理论,以初始吸附热表征的亲和力系数作为调节参数,对测定的吸附平衡数据进行了关联,实验数据均落在一条特征曲线附近,得到了满意的结果.     

Separation of CO2 and CH4 on CaX zeolite for use in Landfill gas separation

In this study, adsorption separation of main components of landfill gas, methane (CH₄) and carbon dioxide (CO₂) was carried out. Henry's law constants, limiting heat of adsorption values, pure and binary isotherms for CO₂ and CH₄ were determined for CaX zeolite adsorbent. Pure isotherm data were compared to those for NaX zeolite from previous studies. The CO₂ adsorption capacity of CaX was greater than that of NaX; however, NaX's separation factor was higher. The heat of adsorption for CO₂ for CaX was higher than those for NaX. © 2013 Canadian Society for Chemical Engineering     

A comparison of isotherm and kinetic models for binary-solute adsorption to affinity membranes

Single-solute isotherms for pepsin (EC 3.4.23.1) and chymosin (EC 3.4.23.4) adsorption to affinity membranes were fitted using five of the most popular isotherm models. It was found that the single-solute Langmuir isotherm was the best two-parameter model, although the three-parameter models gave even better fitting. Experimental binary-solute adsorption isotherms were compared with four different types of binary-solute Langmuir models using the single-solute parameters. The results showed that the difference in the saturation capacities affected the adsorption equilibrium. Furthermore, three types of binary-solute Langmuir models were converted into the kinetic form and used to calculate the association rate constants of pepsin and chymosin from experimental data. The best-fitted rate constant values were found to be identical for different kinetic models. However, the model predictions of association curves were significantly influenced when the values of association rate constants were changed.