苯酚在活性炭上的吸附平衡和吸附动力学

分别采用Freundlich模型和Langmuir模型对苯酚在活性炭上的吸附等温数据进行了拟合分析,并通过改变活性炭添加量和苯酚初始质量浓度研究苯酚在活性炭上的间歇搅拌槽吸附动力学;同时,在非线性吸附等温条件下,采用有限元法求解了包含液膜传质阻力和表面扩散阻力的均相扩散模型(HSDM),结合最小二乘法(单纯形法和麦夸尔特法交替计算)来获得液膜传质系数kf和表面扩散系数Ds,在采用麦夸尔特法估算参数的同时,对参数进行了给定区间的置信区间分析.结果表明:Langmuir模型能较好地描述苯酚在活性炭上的吸附等温曲线;HSDM可以有效预测苯酚在活性炭上的动态吸附行为;在一定搅拌速度下,活性炭添加量和苯酚初始质量浓度对液膜传质系数和表面扩散系数基本无影响;液膜传质系数远大于表面扩散系数,表明苯酚在活性炭上的动态吸附过程是由表面扩散控制的;所估算的kf值相对Ds值更为准确.     

溶解度参数法筛选油品脱氮萃取剂的研究

为了提高润滑油的质量,必须对其进行溶剂萃取脱氮精制处理。用改进的溶解度参数法在不同温度下定量估算萃取溶剂对溶质的溶解能力和选择性,并进行排序,结果表明溶剂的溶解能力与选择性是互相矛盾的。其中溶解能力与选择性可用无限稀释活度系数表示,而无限稀释活度系数用Helpinstill-Van Winkle推算法计算。选择五种溶剂对减压侧线油进行萃取实验并测定溶剂对油品中碱氮化合物的萃取效果,结果表明,理论估算结果与实验测定结果基本吻合。兼顾溶剂对碱氮化合物的溶解能力与选择性,在五种溶剂中BMA是性能较优的油品脱碱氮溶剂。     

醇水体系渗透汽比膜分离过程的溶解-扩散模型

采用溶解－扩散模型，对三醋酸纤维素膜用于乙醇－水休系渗透汽化分离过程进行数学模拟，计算膜的渗透通量和分离因子，计算结果与实测值基本相符。通过模拟计算求出了组分在膜内浓度分布，表明膜近真空侧存在一很薄的“干膜区”。     

不同水模型的甲醇水混合溶液的扩散性质

本文对不同水模型的甲醇水混合溶液的扩散性质做了研究,模拟所得结果与文献值很接近。甲醇的扩散系数随甲醇质量浓度增加而增大,TIP3P、TIP4P,TIP5P水的扩散系数随甲肆浓度增加而减小,采用TIP4P和TIP5P水模型所得结果与实验值更为接近,TIP3P水模型扩散系数较实验值精有偏低。     

用于乙腈废液脱水渗透汽化膜的溶胀实验研究

采用KOCH复合膜对乙腈废液进行溶胀实验研究,考察了不同乙腈浓度的浸泡液对复合膜溶胀性能的影响,发现该复合膜对水优先吸附溶解,为亲水性优先透水膜。同时在料液浓度为84%左右时,复合膜的总溶胀度达到最大值1.8,此膜片适用于乙腈废液体系的脱水分离。     

Pb(Ⅱ)在Nafion修饰电极上的机理研究 (Ⅱ)富集过程中的离子交换和物理扩散

测定Pb(Ⅱ)在Nafion修饰电极上离子交换富集过程中的离子交换系数及物理扩散系数,提出了该过程中,Pb(Ⅱ)在Nafion膜中的浓度分布模型和Pb(Ⅱ)离子交换与扩散模式.     

聚乙烯醇渗透汽化分离膜的研究进展

在描述聚乙烯醇(PVA)成膜工艺制取不同类型的分离膜以及PVA膜的改性处理技术的基础上,给出了PVA膜渗透汽化(PV)分离有机物/水、有机物/有机物混合物的性能,讨论了交联剂、复合膜的支撑膜、高分子网络结构等对膜分离性能的影响,并分析了PV操作参数如料液浓度、操作温度等对分离性能的影响。提出了PVA膜在今后研究开发中的3个方向。     

丁二烯在聚苯乙烯和丁苯多嵌段共聚物膜中扩散系数的测定与计算

用石英弹簧法测定了298．15K和308．15K下丁二烯在聚苯乙烯和丁苯多嵌段共聚物膜中的吸收曲线,结果表明丁二烯在聚苯乙烯膜和丁苯多嵌段共聚物膜中的吸收曲线近似呈费克型,扩散吸收曲线的形态与相对分子质量及其分布无关。用黄永民等的吸附一吸收双模式模型对实验结果进行了关联,获得无限稀释扩散系数和平衡溶解度。     

醇在水中的无限稀释扩散系数的分子动力学模拟

采用分子动力学(MD)模拟研究了0.1 MPa、298~318 K条件下甲醇、乙醇、1-丙醇在水中的无限稀释扩散系数(D12),并通过径向分布函数、配位数、平均氢键数的计算,分析了二元流体的微观结构和分子间的相互作用。结果表明,模拟所得的无限稀释扩散系数与实验值符合。另外,随着温度升高,径向分布函数的峰高、醇分子与水分子之间的配位数以及醇-水的平均氢键数均减小,表明在较高温度下醇分子周围堆积的水分子数减少,醇分子和水分子之间的相互作用力降低,因而使扩散系数增大,这些结果从微观角度解释了扩散系数的变化规律。     

离子液体的无限稀释活度系数测量过程分析

摘要：离子液体受到结构上不对称性、静电作用等多种作用影响,系数特征容易发生形变,传统的测量方法在干扰状态下,很难准确测量。提出一种新的无限稀释活度系数测量模型(MCS-SVM)。通过实验测量与无限稀释活度系数相关的溶质参数,并将它们分成为训练集和测试集;然后将训练集输入到一种最小二乘支持向量机分类模型,并进行的活度系数,完成最优的无限稀释活度系数测量消除测量误差。仿真结果表明,相对于传统测量方法,该模型可以准确描述无限稀释活度系数与溶质参数的非线性关系,提高了无限稀释活度系数的测量精度。     

基于实码遗传算法的河流水质模型的参数估计

针对理想条件下采用解析法往往导致水质参数估计较大误差的问题,以及针对含有多参数的二维水质模型的参数估计问题,具体介绍了采用有限单元法和实码遗传算法求解二维水质模型未知参数的基本步骤,对水质参数(包括纵向、横向弥散系数和衰减系数)分别进行编码,通过计算机模拟浓度输出,并与实测值比较从而得出最优的水质参数估计值．算例表明,采用有限单元法-遗传算法估计河流水质模型的参数是可行的．     

Preparation and Properties of Chitosan/Polyvinyl Alcohol Blended Fiber Membrane for Medical Dressing

The antibacterial dressing prepared by the electrospinning can play a role in protecting the wound,preventing infection and promoting wound healing, and have broad application prospects. Chitosan( CS)/polyvinyl alcohol( PVA) blended fiber membrane was successfully prepared by electrospinning. The fiber morphology,thermal properties and material composition of CS/PVA blended fiber membrane were studied,and the interaction between CS and PVA was analyzed,and the optimum blend ratio was also determined. Then glutaraldehyde( GA) steam cross-linking of the blended fiber membrane was carried out in order to improve the water resistance of the fiber membrane. At the same time,the effect of different crosslinking time on the water resistance of fiber membrane was investigated. The apparent morphology of the fiber membrane was observed by a scanning electron microscope( SEM). The results showed that with the increase of spinning solution concentration,the morphology of the fiber became more and more regular,and the fiber diameter increased gradually. The intermolecular interaction between CS and PVA was found by Fourier transform infrared( FTIR) spectroscopy and thermal properties, which improved the spinnability of CS electrospinning. After crosslinking,the water resistance of the fiber membrane was greatly improved,among which the effect of 4 h crosslinking was the best,and the water resistance of the fiber membrane increased by 64.89%.     

渗透汽化膜技术回收含水异丙醇的工业研究

采用渗透汽化膜技术对头孢曲松钠生产过程中的异丙醇回收进行了实验,并与原有的盐萃取回收工艺进行了比较.实验考察了渗透汽化膜的脱水分离性能,并为工业设计提供基础性数据.结果表明,含水量为15%(质量分数,下同)的异丙醇经渗透汽化膜脱水后得到含水量≤1%的异丙醇,处理量为6 000 kg/d.该工艺具有低能耗、低污染的优势,...     

PVA/TEOS/GA杂化膜的制备及溶胀吸附性能

采用溶胶-凝胶法(sol-gel)制备了PVA/TEOS/GA有机/无机杂化膜,比较杂化膜在3种不同温度下在乙醇/水全浓度范围的溶胀性能,分析无机相和交联剂对PVA膜溶胀性能的影响.比较不同溶胶-凝胶反应条件及不同热处理条件对膜溶胀度和溶解选择性的影响.用FTIR和XRD对杂化膜结构进行分析表征.结果表明PVA与无机相(TEOS)发生溶胶-凝胶反应生成氢键和共价键Si-O-Si,形成交联有机聚合物/无机杂化体系,使杂化膜的结晶度减少,控制了膜的溶胀,提高膜的溶解选择性能,但膜的溶胀减少会使通量有所下降.加入GA后,使PVA杂化膜溶胀度和溶解选择性都有所提高,表明PVA杂化有利于控制膜在乙醇/水溶液中的溶胀,从而提高膜的分离性能.     

PVA与PAN复合膜分离乙醇—水溶液的渗透汽化放大试验

在渗透汽化放大试验装置上,针对乙醇水体系,考察了板框式膜组件的结构合理性和大面积复合膜的稳定性,研究了不同料液流量、料液浓度和料液温度对膜分离性能的影响。实验结果表明,大膜分离性能稳定,膜分离性能在料液流量为０２～０８０Ｌ／ｓ的范围内基本不变,并且总渗透通量及水通量的对数值与料液浓度、料液温度的倒数分别呈线性关系;超薄板框式膜组件设计合理,结构紧凑,有效地抑制了膜料液侧的浓差极化。     

膜结构填料的材料特性对甲醇/异丙醇精馏分离的影响

以聚偏氟乙烯（PVDF）、聚丙烯（PP）、聚砜（PS）和聚四氟乙烯（PTFE）4种材料作为中空纤维膜结构填料对甲醇与异丙醇混合体系进行精馏分离研究。从塔顶馏出液浓度、等板高度和传质系数三方面比较了4种膜结构填料的优劣,并从膜的材料特性和微观结构角度对结果进一步分析,得出聚偏氟乙烯膜结构填料比较适合于精馏分离甲醇与异丙醇体系的结论。     

Effects of drug-polymer dispersions on solubility and <Emphasis Type="Italic">in vitro</Emphasis> diffusion of artemisinin across a polydimethylsiloxane membrane

Artemisinin(ART) is a sesquiterpene lactone with an endo-peroxide bridge that is thought to be responsible for its antimalarial activity.It has low oral bioavailability because of aqueous insolubility,which leads to local toxicity at the site of aggregation.The present work focused on increasing its solubility and evaluating its permeation across a model membrane to mimic transdermal delivery that bypasses the hepatic metabolism.For this purpose,physical mixtures(PM),solid dispersions(SD) and lyophilized dispersions(LD) with different drug-polymer ratios(1:0.5,1:1,1:2,1:4 and 1:9) were prepared using the hydrophilic polymer polyvinylpyrrolidone(PVP).Drug-polymer dispersions were characterized using X-ray diffraction(XRD) and Fourier transform infrared spectroscopy(FTIR).Solubility was measured in three solvents:de-ionized water,phosphate buffered saline(PBS) and methanol.The toluene-water partition coefficient was evaluated and compared with the literature and calculated logP values.In vitro diffusion of ART was studied across a polydimethylsiloxane membrane from a saturated solution of drug-polymer dispersions.XRD patterns showed a gradual decrease in crystallinity of ART with increasing polymer concentration,while FTIR confirmed no interactions between ART and PVP.Solubility was increased up to 4-,5-and 8-fold for LD in water,PBS and methanol,respectively.The logP for toluene-water was 2.65 ± 0.3,which is in good agreement with literature and calculated logP values.Permeation was enhanced,which is attributed to the decrease in crystallinity and increase in wettability of the drug.The ART flux was significantly higher than that of pure ART(0.12 ± 0.01) with increasing PVP concentration for SD and LD formulations.In conclusion,drug-polymer dispersions with PVP improve the pharmaceutical properties of ART in the order LD>SD>PM.     

渗透汽化膜分离耦合酯化反应的研究(Ⅰ)──丙酸/异丙醇的酯化反应及其过程参数

对耦合渗透汽化膜分离的等摩尔的丙酸／异丙醇酯化反应过程进行了研究；并考察了温度、投料量、催化剂浓度和膜厚等因素对反应的影响．结果表明：耦合膜分离可以有效地提高酯化反应的转化率；升高反应温度和增加催化剂浓度可以缩短反应达到平衡的时间，有利于提高膜分离的效果；提高A膜／V反（料液体积）的比值，可以更快地降低反应体系的水浓度和提高该反应的转化速率．     

Coupled Pervaporation-Reaction Distillation Process for the Production of n-Bromopropane

IntroductionThere are several industrializable membraneseparation techniques,such as reverse osmosis(RO) ,nanofiltration(NF) ,ultrafiltration(UF) ,dialysis(D) ,electric dialysis(ED) ,gas separation(GS) and pervaporation (PV) [13] . In recentyears,another application of membrane technology tocoupled reaction- separation processes has receivedspecial attention from academic circles andindustrial enterprises[4 7] . When separationmembranes are incorporated into a reversiblereaction system co…