长度及出水方式对中空纤维膜过滤性能的影响

为了更好的对中空纤维膜组件进行优化设计,通过对4组试验的对比,就中空膜纤维的长度和膜组件出水方式对过滤性能的影响进行考察.结果表明:无论是静态过滤还是曝气条件,在试验周期内,单端出水组件的膜比通量要比双端出水组件的变化趋势更为平缓.相同条件下,双端出水组件的平均通量要高于单端出水组件.静态过滤条件下,双端比单端的稳定运行通量有较大提高;在曝气条件下,由于气泡诱发的纤维抖动和水力错流作用,曝气对通量的影响要大于出水方式对通量的影响.在本研究的条件下,固定曝气强度为7.99 m3/(m2·h),100～120 cm为单端出水的膜纤维最佳长度设计值,在此范围内膜比通量与短纤维相比不会有明显的降低.当组件的出水方式改为双端时,膜纤维的最佳设计长度可延长至120～140 cm.     

双层刮膜法制备的微孔膜应用于悬浮液澄清的研究

将双层刮膜法制备的具有高开孔率表面的微孔膜应用于过滤高浓度悬浮液体.研究了悬浮液颗粒浓度、粒径大小、膜的初始纯水通量、膜的正反面以及过滤方式几个方面对膜过滤性能的影响.结果表明,膜的初始纯水通量对颗粒的截留率和过滤通量的稳定性几乎没有影响;在一定的误差范围内,悬浮物的浓度对膜的稳定通透性能起着决定性的作用;颗粒粒径越大初始通量就越大.PSf膜的正面过滤初期通量没有底面过滤的大,但稳定通量始终高于底面过滤的稳定通量.PSf膜对啤酒的过滤效果优于PES膜,能过滤啤酒的最大质量Gmax是PES膜的4倍多,所以,具有高开孔率表面的PSf膜可以接纳更多的污染物质,具有较好的过滤性能.对于高浓度悬浮液的澄清来说,错流过滤的效率要高于死端过滤.     

膜表面纳米TiO_2修饰层的构建及其抗蛋白质污染性能研究

采用纳米二氧化钛胶体和多巴胺作为修饰剂,通过多巴胺的氧化自聚将纳米二氧化钛颗粒沉积到聚丙烯微孔膜(MPPM)的表面.采用FTIR和SEM对膜进行了表征,发现修饰后膜表面多孔形态未发生变化,仅在膜表面均匀地负载着大量的纳米TiO_2颗粒.静态水接触角及纯水通量测试结果显示,修饰膜具有优异的润湿性,在0.10MPa下,MPPM的纯水通量为0,而经纳米TiO_2修饰后的膜纯水通量可稳定在4 625L/(m2·h)左右.蛋白质静态吸附与蛋白质溶液过滤研究结果表明,修饰膜具有良好的抗蛋白质污染性能,蛋白质溶液通量下降率仅为35%,且膜表面的蛋白质可用水清洗除去,通量恢复率达83%.     

超、微滤过程中临界通量的研究进展

介绍了超滤、微滤膜过滤过程中临界通量的定义及其形成机理;总结了对临界通量的测定方法;分析了影响临界通量的因素;对临界通量的前景进行了展望.     

弯曲板式膜系统在生物发酵澄清除杂中的应用

自主设计了弯曲板式膜系统,优化了膜壳和膜元件,使得系统能够获得稳定的通量和高质量滤液.该系统对赤霉素过滤的通量可以稳定在65 L/(m2·h);对于头孢C的过滤,通量可以稳定在15 L/(m2·h),系统对二者的蛋白截留率超过85％.     

微滤膜过滤阻力机理及模型研究

研究微滤膜过滤阻力机理及其通量的变化是该工艺应用推广需要解决的关键.以Langmuir理论和Darcy定律为基础,从理论上证实了浓度极化阻力与凝胶层阻力是同一性质的阻力,并通过Langmuir关系式统一起来,推导了微滤膜过滤阻力的数学模型.然后采用一体式膜过滤反应器过滤乳化油实验对该模型进行了验证.实验结果与膜过滤阻力模型拟合得很好(R2=0.9912),膜表面极化浓度与相对过滤压差成线性关系,比例系数为凝胶层浓度.基于Langmuir理论的微滤膜过滤阻力模型能真实反映凝胶层阻力的形成过程.用该模型得到的沉积平衡系数Φ反映了混合液的浓度、颗粒大小、温度和黏度等过滤特性,并把极限通量JVlim与混合液过滤特性联系起来,极限通量与过滤压差无关.     

外置式动态膜生物反应器处理生活污水

采用孔径为30 μm的工业滤布、硬质PVC管支撑体、不锈钢管套构造外置式膜生物反应器,观察不同过滤压差对动态膜形成及出水通量和浊度的影响,并研究其对生活污水的处理能力.结果表明,过滤压差对动态膜的形成及出水通量的影响比较复杂,10 min～2 h出水通量随过滤压差增大而增大,但48 h后出水通量随过滤压差增大而减小.研究还发现,系统稳定运行后出水通量随膜表面错流速度增大而增大.综合分析,本试验选取过滤压差为0.04 MPa为最优过滤压差,动态膜40min内可形成且保持稳定.反应器稳定运行后,出水水质良好,对COD、NH3 -N、TN、TP的平均去除率分别为96.68％、96.64％、71.46％、57.80％,出水浊度1.0以下.     

聚乙烯丙烯酸对PVDF膜的共混改性研究

在不同溶剂条件下,以聚偏氟乙烯(PVDF)作为膜材料,通过浸没沉淀相转化法制备了一系列的聚乙烯丙烯酸(EAA)共混的改性PVDF膜,并通过测定改性PVDF膜的形态结构、接触角、机械强度以及蛋白质静态吸附量,考察了溶剂的种类及添加剂的加入对膜性能的影响.研究结果表明,EAA的加入一定程度上改善了膜的亲水性及疏油性,以DMAc作为溶剂所制备的共混改性膜具有较优的亲水疏油性能.与未改性膜相比,改性膜过滤BSA溶液和SA溶液相对通量衰减率降低,通量恢复率上升,膜的抗污染性能得到提高.其中过滤BSA溶液时的通量恢复率达100%,不可逆污染指数为0.     

气提有机管式膜工艺精制卤水研究

采用气提有机管式膜过滤工艺进行卤水精制,研究了曝气量、膜面流速、跨膜压差、背压、反洗强度对膜通量的影响,并计算了过滤阻力及系统能耗.实验结果表明随着系统曝气量、跨膜压差、背压的增大,膜通量增加,而膜面流速对膜通量影响较小,反洗周期定为15min.计算结果表明,与错流过滤工艺相比,该工艺利用气液两相流的不稳定性能有效降低膜过滤阻力,并显著降低能耗.     

陶瓷膜处理聚驱采油废水过程中膜通量预测回归模型的建立与检验

对陶瓷膜处理聚驱采油废水过程中的膜通量预测回归模型进行了建立及检验.通过析因交叉试验设计,分别考察了不同膜面流速和跨膜压差下的瞬时膜通量和24 h内平均膜通量的变化情况;在析因交叉试验的结果上,基于ColinMaclaurin数学原理建立了陶瓷膜处理聚驱采油废水的膜通量预测回归模型,通过Matlab软件对模型的等高线图和响应曲面图进行了拟合;对膜通量预测回归模型分别进行了理论检验和试验检验.理论检验结果表明,模型和预测值的标准残差均在±2.00的范围内,预测膜通量和实测膜通量具有相似的统计学分布特征;试验检验结果表明,除模型自变量区间端点处的预测膜通量和实测膜通量误差相对较大外(约14.6%),其余误差均小于8%,说明该膜通量预测回归模型具有较高的准确度,为陶瓷膜水处理过程中的运行参数优化以及给定运行条件下的膜通量预测提供了一种研究方法.     

润滑油酮苯脱蜡溶剂回收用聚酰亚胺纳滤膜分离性能的研究

主要研究了聚酰亚胺纳滤膜分离酮苯一润滑油的性能．考察了操作压力、温度、料液流量、料液中润滑油浓度及酮苯比等因素对膜通量和截留率的影响,并考察了长期运行情况下膜的分离性能．结果表明,随压力增大、温度升高和料液流量增大,膜通量也随之增大;料液中润滑油浓度的增加使膜通量减小,料液中酮苯比的增加可增大膜的通量;以上各种情况对膜的截留率影响不大,截留率稳定在95％以上;在40天的运行期内膜的分离性能变化不大,说明此聚酰亚胺膜具有较强的抗污染能力．     

膜法分离氨淋洗吸附钼钨树脂后淋洗液中的氨

以钨湿法冶金中的一种氨淋洗吸附钼钨树脂后淋洗液为料液,采用膜分离技术实现氨的分离.通过比较多种纳滤和反渗透膜对钼钨与氨的分离效果,从中选择了一种合适的低压反渗透膜,考察了膜分离过程中原料液浓度、操作压力、浓缩比、温度因素对透过液通量、钼钨截留率、氨回收率(或透过率)以及钼钨与氨分离系数的影响,在操作压力2.41MPa,温度在36℃,浓缩比为4∶1的条件下,透过液通量达27 L/(m2·h),Mo、WO3的截留率接近100％,Mo、WO3与NH3的分离系数分别达18和51,料液中76％的氨得到回收.以实验室的试验结果为依据,选用低压反渗透膜用于工业生产,取得了良好的效果.     

蒸汽渗透法有机溶剂气相脱水

蒸汽渗透法是一种膜法气相脱水技术，与渗透汽化不同，在该过程中，进料的蒸汽与膜直接接触，在高于料液沸点的温度下进行操作，可以采用提高压力和温度等手段提高分离膜的透过通量，并可以与分馏过程集成使用，简化化工操作单元，要求所使用的膜具有更好的高温耐溶性性能。文章综述近几年２５篇有关文献，介绍蒸汽渗透过程的特点、与渗透汽化的对比、使用的膜以及其应用前景。     

超滤膜渗透通量法评价水质的研究

提出了一种通过超滤膜水的渗透通量或渗透体积评价水质污染状态的新方法．从我国不同地区取来18种水质,包括井水、河水、海水、湖水,并用固定超滤膜的超滤实验装置进行了测试,水渗透体积和水通量随时间的变化可以表征水样中污染物的含量,以此描述水质的差别．由串联阻力模型推导出的修正污染指数（MFI）数学关系并结合渗透体积和水通量的实验数据拟合出18种不同水质的MFI．结果表明,水渗透体积随时间、渗透通量随时间及操作压力的变化与MFI值是一致的．并且从膜污染的理论上解释了超滤膜的实验结果．     

Transdermal Iontophoretic Delivery of Thyrotropin-Releasing Hormone Across Excised Rabbit Pinna Skin

Enhanced transport of a model peptide drug thyrotropin-releasing hormone (TRH), a tripeptide of molar mass 362 g and a pK_a 6.2, through excised rabbit pinna skin was achieved by means of iontophoresis with continuous current or monophase periodically pulsed current. The resulting flux in the steady state was proportional to the applied current density. In the transdermal iontophoretic delivery of TRH, the pulsed iontophoretic flux exceeded that obtained with a continuous current. At a low ionic strength, an increased degree of protonation in TRH increased the rate of permeation. The flux of TRH in a buffer at pH 4 is greater than that at pH 8 when the ionic strength is 0.1 M. At a greater ionic strength, the trend is reversed. The enhanced flux of unprotonated TRH during transdermal iontophoresis is attributed largely to electro-osmotic volume flow. An increased rate of permeation of TRH crossing the skin is achieved at low ionic strength, moderate pH, and a large duly cycle of current; the frequency of pulsed current had no significant influence on the rate of transdermal iontophoretic delivery of TRH.     

并流条件下聚丙烯中空纤维微孔膜的过滤特性

采用死端过滤（并流）对两种聚丙烯中空纤维微孔膜的低浊度水过滤性能进行了实验研究,并采用滤饼理论对聚丙烯微孔膜的过滤特性进行了描述．当被处理体系的阻力由膜阻力控制时,由于滤饼阻力的增加使得渗透通量快速衰减;当过程阻力由膜阻力和滤饼阻力共同主导时,渗透通量衰减变缓．在过程初期滤饼阻力与渗透总量成线性关系,但后期有偏离这种线性关系并有快速增大的趋势．分析结果表明,在相同渗透量下滤饼阻力的增加不仅与滤液本身性质有关,而且与微孔膜材料的本征性质有关,滤饼理论可以很好地解释聚丙烯微孔膜处理低浊度水溶液时的过滤性能．     

Investigation of structure and oxygen permeability of Ba-Ce-Co-Fe-O system

Mixed ionic-electronic conducting perovskite oxides, BaCe_0.1Co_xFe_0.9−xO_3−δ, were synthesized with a combined citric acid and EDTA complexing method. The structure and oxygen permeability of BaCe_0.1Co_xFe_0.9−xO_3−δ series was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and oxygen permeation operation. XRD characterization showed that pure cubic perovskite structure can be obtained only if the content of cobalt and cerium in B-site of Ba-Ce-Co-Fe-O series is no more than 40% and 15%, respectively. Lattice parameters of BaCe_0.1Co_xFe_0.9−xO_3−δ gradually increase with cobalt and cerium content, iodine titration experiment revealed that the doping of cerium ions with big radius can keep B-site cobalt and iron ions in low valence state. Oxygen permeation operation showed that oxygen permeation flux of all BaCe_0.1Co_xFe_0.9−xO_3−δ membranes gradually increases with testing time in the initial stage, and the time to reach steady state becomes longer with the increase of cobalt content. After reaching permeation steady state, BaCe_0.1Co_0.4Fe_0.5O_3−δ exhibits highest oxygen flux amongst BaCe_0.1Co_xFe_0.9−xO_3−δ series.     

Transdermal Iontophoretic Delivery of Thyrotropin-Releasing Hormone Across Excised Rabbit Pinna Skin

Abstract

Enhanced transport of a model peptide drug thyrotropin-releasing hormone (TRH), a tripeptide of molar mass 362 g and a pK_a 6.2, through excised rabbit pinna skin was achieved by means of iontophoresis with continuous current or monophase periodically pulsed current. The resulting flux in the steady state was proportional to the applied current density. In the transdermal iontophoretic delivery of TRH, the pulsed iontophoretic flux exceeded that obtained with a continuous current. At a low ionic strength, an increased degree of protonation in TRH increased the rate of permeation. The flux of TRH in a buffer at pH 4 is greater than that at pH 8 when the ionic strength is 0.1 M. At a greater ionic strength, the trend is reversed. The enhanced flux of unprotonated TRH during transdermal iontophoresis is attributed largely to electro-osmotic volume flow. An increased rate of permeation of TRH crossing the skin is achieved at low ionic strength, moderate pH, and a large duly cycle of current; the frequency of pulsed current had no significant influence on the rate of transdermal iontophoretic delivery of TRH.     

Basil Oil is a Promising Skin Penetration Enhancer for Transdermal Delivery of Labetolol Hydrochloride

Thepresent work investigates effectiveness of basil oil, a volatile oil containing alcoholic terpenes, as a potential penetration enhancer for improved skin permeation of labetolol hydrochloride (LHCl) with reference to camphor, geraniol, thymol, and clove oil. Saturation solubilities of LHCl were determined in water, vehicle (ethanol:water, 60:40 v/v) and vehicle containing 5% w/v terpenes. Comparable (P > 0.05) saturation solubilities were found suggesting an insignificant increase in LHCl flux across rat skin on account of thermodynamic activity. Permeation of LHCl in vehicle per se and in presence of 5% w/v enhancer was investigated by performing in vitro rat abdominal skin permeation studies using a side-by-side glass diffusion cell. Various parameters viz. steady state flux, permeability coefficient, lag time, partition coefficient, diffusion coefficient, and enhancement ratios (ER) were calculated from the permeation data. Basil oil produced the maximum enhancement (ER?=?46.52) over neat vehicle, among all enhancers. Activation energies for LHCl permeation in water, vehicle per se and in presence of 5% w/v basil oil were found to be 23.16, 18.71, and 10.98 kcal/mole, respectively. Lowering of activation energy in presence of basil oil suggests creation of new polar pathways in the skin for enhanced permeation of LHCl. Basil oil is proposed as a promising penetration enhancer for improved transdermal drug delivery of labetolol.     

Basil oil is a promising skin penetration enhancer for transdermal delivery of labetolol hydrochloride

The present work investigates effectiveness of basil oil, a volatile oil containing alcoholic terpenes, as a potential penetration enhancer for improved skin permeation of labetolol hydrochloride (LHCl) with reference to camphor, geraniol, thymol, and clove oil. Saturation solubilities of LHCl were determined in water, vehicle (ethanol:water, 60:40 v/v) and vehicle containing 5% w/v terpenes. Comparable (P > 0.05) saturation solubilities were found suggesting an insignificant increase in LHCl flux across rat skin on account of thermodynamic activity. Permeation of LHCl in vehicle per se and in presence of 5% w/v enhancer was investigated by performing in vitro rat abdominal skin permeation studies using a side-by-side glass diffusion cell. Various parameters viz. steady state flux, permeability coefficient, lag time, partition coefficient, diffusion coefficient, and enhancement ratios (ER) were calculated from the permeation data. Basil oil produced the maximum enhancement (ER = 46.52) over neat vehicle, among all enhancers. Activation energies for LHCl permeation in water, vehicle per se and in presence of 5% w/v basil oil were found to be 23.16, 18.71, and 10.98 kcal/mole, respectively. Lowering of activation energy in presence of basil oil suggests creation of new polar pathways in the skin for enhanced permeation of LHCl. Basil oil is proposed as a promising penetration enhancer for improved transdermal drug delivery of labetolol.