模拟的发酵液组分对聚二甲基硅氧烷/陶瓷复合膜渗透汽化性能的影响

对所制备的聚二甲基硅氧烷（PDMS）/陶瓷复合膜进行了渗透汽化性能表征。通过在乙醇-水混合体系中添加不同的模拟发酵液组分;如葡萄糖（多羟基醛）、甘油（多元醇）、丁二酸（有机酸）、KCl（无机盐）;考察了各组分对复合膜渗透汽化性能的影响。研究发现：在333 K下;在乙醇浓度为65 g·L-1的混合物中添加不同浓度的第三组分;有机添加物对膜的渗透汽化性能没有明显影响;而无机盐的加入使膜的分离因子稍有提高。所制备的PDMS/陶瓷复合膜;在上述渗透汽化过程中表现出良好的稳定性和对乙醇的优先选择性;渗透通量和分离因子（醇/水）分别在4.5～4.7 kg·m^-2·h^-1、8.3～10.3之间。     

PTFE对PDMS复合膜在低浓度有机物水溶液中渗透汽化性能的影响

制备了聚四氟乙烯（PTFE）超细粉体填充聚二甲基硅氧烷（PDMS）复合膜,通过扫描电子显微镜、傅里叶变换红外光谱仪、热失重分析仪等测试仪器对复合膜进行了表征,利用低浓度有机物（乙醇、丙酮、正丙醇）水溶液体系进行渗透汽化,并由单组分溶解实验计算了有机物（乙醇、丙酮、正丙醇）在复合膜中的溶解度。结果表明,PTFE含量由0增加至10 %（质量分数,下同）时, 复合膜的表面积及热稳定性得到了提高,有机物乙醇、丙酮、正丙醇在复合膜中的溶解度分别由0.0923、0.1589和0.2691 g/g提高至0.0991、0.1678和0.2773 g/g;加入PTFE后提高了复合膜的渗透汽化性能。     

PDMS/PTFE沸石填充复合膜及渗透汽化性能研究

以MFI疏水沸石作为填充剂,制备了PDMS（聚二甲基硅氧烷）/PTFE沸石填充复合膜,并利用SEM、XRD等手段对其进行了表征。以环己酮/水溶液为分离实验体系,考察了沸石填充量对PDMS/PTFE沸石填充复合膜渗透汽化性能的影响。     

PSF支撑层结构对PDMS复合膜渗透汽化性能的影响

以4种不同结构的聚砜(PSF)作为支撑层,制备PDMS/PSF渗透汽化复合膜,考察其用于乙醇/水体系的分离性能,以研究支撑层结构对渗透汽化复合膜分离性能的影响。采用SEM和EDX分析复合膜表层结构,结果表明,支撑层结构几乎不影响复合膜的选择性,但对膜通量有较大影响,特别是支撑层的表面结构对复合膜性能的影响比断面结构更明显。     

有机硅烷交联PDMS/陶瓷复合膜的制备及渗透汽化汽油脱硫性能

采用有机硅烷γ-氨丙基三甲氧基硅氧烷（APTMS）,对聚二甲基硅氧烷（PDMS）进行交联改性,以ZrO₂/Al₂O₃陶瓷复合膜为支撑体,制备了一系列有机硅烷交联的PDMS/陶瓷复合膜。通过扫描电镜（SEM）、傅里叶红外光谱（FTIR）、热重分析（TGA）对改性效果和膜结构进行了表征。将所制备的PDMS/陶瓷复合膜应用于渗透汽化脱除模拟汽油中的有机硫化物（噻吩）,考察了交联剂APTMS含量、操作温度、料液含硫量等因素对复合膜渗透汽化脱硫性能的影响。实验结果表明,有机硅烷交联的PDMS膜相比于传统正硅酸乙酯（TEOS）交联的PDMS膜,通量和硫富集因子均有所提高。随着进料温度和原料液中硫含量的升高,膜的渗透通量均增大,而硫富集因子均减小。当APTMS质量分数为15%、进料温度为25℃、噻吩质量浓度为100mg/kg时,渗透通量为0.46 kg/（m²·h）,硫富集因子达到3.5。     

聚乳酸/硅橡胶复合富氧膜的制备与性能

以聚乳酸(PLA)为基膜材料,通过静电纺丝技术制备聚乳酸纤维基膜,Si-69为改性剂进行处理的硅橡胶作为涂敷层,制备聚乳酸/硅橡胶复合富氧膜.利用傅里叶红外光谱(FTIR)分析、X-射线衍射(XRD)分析对制备的复合膜的结构及两相间距进行分析.探究了不同Si-69用量对聚乳酸/硅橡胶复合膜力学性能及透氧性能的影响.结果表明,最佳交联剂Si-69用量为5％,此时交联效果最好,PLA、PDMS和PDMS、PDMS相间距明显减小,PLA/PDMS复合富氧膜断裂伸长率为125％,同时表现出更好的透气性能,其氮氧分离系数高达4.2,比硅橡胶富氧膜提高281％.     

SiO_2/PDMS/PVDF复合膜渗透蒸发回收煤化工废水中酚

采用PVDF中空纤维为基膜,以Si O_2填充PDMS溶液为涂覆液,进行动态负压涂覆,制备Si O_2/PDMS/PVDF复合膜材料,回收处理煤化工废水中的酚。通过扫描电镜(SEM)、能量弥散X射线能谱仪(EDS)及接触角测试仪对Si O_2/PDMS/PVDF复合膜材料进行了表征,并研究了Si O_2质量浓度、涂覆时间对Si O_2/PDMS/PVDF复合膜材料渗透蒸发性能的影响。当Si O_2填充质量浓度占PDMS质量浓度的12%,涂覆时间60 min条件下,制得的Si O_2/PDMS/PVDF复合膜具有最佳的渗透蒸发性能。保持进水温度50℃,膜后压力50 k Pa,进水流速10 L/h,酚通量达到7.16 g/(m~2·h),分离因子为4.26。     

偶联剂对纳米二氧化硅/PDMS复合膜渗透汽化性能影响的研究

用3种硅烷偶联剂3-氨丙基三乙氧基硅烷(AMES)、γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(MEMS)、十六烷基三甲氧基硅烷(HEMS)分别对纳米二氧化硅粒子进行改性,利用制备的改性粒子与PDMS制备了一系列平板复合渗透汽化分离膜,用于乙醇/水溶液分离.实验结果表明:复合膜的渗透汽化性能得到显著的提高.3种改性粒子在提高渗透通量方面:HEMS＞MEMS＞ AMES;在提高分离因子方面,MEMS与AMES对复合膜的影响十分接近,而HEMS远小于前两者.当MEMS改性二氧化硅的质量分数为4％时,在40℃质量分数为10％的乙醇/水溶液中,复合膜的分离因子达到最高值11.17,渗透通量为216.1g/(m2 ·h).     

聚二甲基硅氧烷-聚偏氟乙烯共混膜制备及其渗透蒸发性能研究

为增强聚偏氟乙烯(PVDF)膜的疏水性能和膜选择性能,在PVDF基膜材料中添加了不同质量的聚二甲基硅氧烷(PDMS),制备了PVDF-PDMS共混复合膜。考察了PDMS、PVDF质量比对复合膜结构性能的影响,并用扫描电子显微镜、比表面积孔径分析仪、接触角测量仪、傅里叶变换红外光谱仪、X射线光电子能谱仪等仪器对复合膜进行了表征;采用低含量苯酚水溶液研究了复合膜的渗透蒸发性能。结果表明,随着PDMS添加量的增加,复合膜的疏水性能、苯酚渗透通量以及分离因子都会逐渐增大,复合膜渗透蒸发性能明显优于未改性膜;在PDMS、PVDF质量比为1:10时,复合膜具有最好的形态结构,表面接触角达到82.92°,苯酚渗透通量为39.31 g/(m~2·h),分离因子增加到4.68。     

有机溶剂纳滤膜的润湿性对渗透和分离性能的影响

有机溶剂纳滤是一种绿色、高效、节能的新型膜分离技术,在回收和处理有机溶剂中具有广泛的应用前景。本文采用浸渍法分别将聚合物聚二甲基硅氧烷（PDMS）、嵌段聚醚酰胺（PEBAX2533）和聚乙烯醇（PVA）与聚砜（PS）超滤基膜复合,制备了3种不同润湿性的聚合物耐溶剂纳滤膜,研究了PDMS/PS、PEBAX/PS和PVA/PS复合膜对甲醇、乙醇、异丙醇、正己烷、正庚烷的渗透性能,考察了3种聚合物膜对伊文思蓝/甲醇溶液的有机溶剂纳滤性能。结果表明,有机溶剂在不同润湿性复合膜的渗透和传递性能与溶剂本身的溶度参数、分子量、黏度和极性等有很密切的相关性,溶剂的分子量、黏度、分子动力学直径越小,在同一极性复合膜中渗透通量越大;对伊文思蓝/甲醇溶液的有机溶剂纳滤分离表明,PDMS/PS和PEBAX/PS复合膜的截留率均可达90%以上,通量分别为 58.0L/(m²·h·MPa)和72.2L/(m²·h·MPa);PVA/PS复合膜的截留率为85.1%左右,通量为57.5L/(m²·h·MPa)。     

Air Separation through Modified Ethyl Cellulose Thin Film Supported on Porous Polyethersulfone

Abstract

Composite membranes for air separation were prepared from a liquid crystal DYC-modified ethyl cellulose (EC) thin film ranging in thickness from 1 to 7 μm and a porous polyethersulfone support with a thickness of 120 μm. The effects of DYC/EC (9/91) solution concentration, water, and operating parameters such as temperature, pressure, and time on the air-separation properties of the composite membranes were examined by a constant pressure—variable volume method. The permeate flux and oxygen concentration of the oxygen-enriched air (OEA) through the membranes increase significantly with increasing operating pressure difference. With decreasing casting solution concentration, or with increasing humidity around the membranes or operating temperature, the OEA flux increases greatly while the oxygen concentration sometimes decrease slightly. An increase in the operating time leads to an OEA flux decline, but the oxygen concentration rose when the operating time was varied for 70 hours. However, a further increase of the operating time from 70 to 500 hours does not lead to further changes of the OEA flux and oxygen concentrations. A thin-film composite membrane exhibits a slightly lower oxygen concentration accompanied by a very significant enhancement in the OEA flux and membrane stability compared to a homogeneous dense membrane of the same materials.     

Actual air separation across multilayer composite membranes

Multilayer composite membranes are fabricated from six types of thin films as selective layers, an ethyl cellulose (EC) thin film as a flexible spacer, and poly(ether sulfone) (PES) with 15–45 nm pore size or 100–120 μm thickness as a porous support layer. The effects of the thin‐film type and its layer number, operating temperature, and transmembrane pressure difference, as well as the operational time on the actual air‐separation properties through the composite membranes, are investigated by a constant pressure‐variable volume method. The results show that a pure polystyrene thin‐film composite membrane exhibits poor actual air‐separation performance due to its brittleness, although it has a higher ideal oxygen over nitrogen separation factor. The oxygen‐enrichment air (OEA) flux through all of the composite membranes tested increases significantly with increasing operating temperature and pressure difference. The oxygen concentration in the OEA increases slightly with an increase in operating temperature, and the oxygen concentration through the polystyrene/cholesteryl oleyl carbonate blend, top layer composite membrane exhibits the maximal value. As the transmembrane pressure difference increases, the oxygen concentration in the OEA also exhibits the maximal value. The maximum oxygen concentration can reach 39.1%, which is achieved by the multilayer composite membrane consisting of a polystyrene/cholesteryl oleyl carbonate (95/5) monolayer, an EC single flexible spacer, and a PES support at 35°C and a transmembrane pressure difference of 550 kPa. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2396–2403, 2000     

新型PVA/PA复合膜的运行工艺对渗透汽化性能的影响

研究了聚乙烯醇（PVA）/聚酰胺（PA）复合膜渗透汽化（PV）分离异丙醇（IPA）/水混合物时运行工艺的影响,模拟了渗透通量（J）预测方程。结果表明,PVA/PA复合膜在料液中w（IPA）%在0～95%范围内或在25℃～100℃的操作温度范围获得的渗透液中IPA含量[w′（IPA）]都小于1%,J随料液中w（IPA）%的下降或操作温度的提高而增加。分离性能预测方程的拟合结果与试验数据有良好一致性。在室温条件下,经过90 d的间歇运行或经过120 d的长期贮存后,PVA/PA复合膜的分离性能稳定,在IPA/水混合物的共沸温度80.4℃运行时的J为73.1 g/m^2·h,渗透液中的水含量[w′（H2O）]都大于99.5%,展示了其在食品、生物、制药和化学等工业中将具有良好的应用前景。     

Bilayer thin-film composite membranes for air separation

Bilayer composite membranes suitable for separating air, consisting of poly(4-methylpentene-1) (PMP) thin film as a selective top layer, an ethylcellulose–heptycellulose (ECHC) blend thin film as a selective sublayer, and polysulfone as a porous support, were investigated using a constant pressure–variable volume method. By varying operating temperature, pressure, time, as well as stage cut, the membranes were characterized for their oxygen enriched air (OEA) flux and oxygen concentration in the OEA permeated in a single step. The results show that both the OEA flux and oxygen concentration through the membranes increase with increasing operating pressure. With the increase of operating temperature, the OEA flux increases largely but the oxygen concentration decreases slightly. The oxygen concentration also decreases slightly with the stage cut. On the contrary, the OEA flux decreases and oxygen concentration increases slightly with operating time. It is found that a PMP thin film plays an important role in enhancing the air-separation capability of the membrane. The PMP/ECHC bilayer thin-film composite membrane could enrich the OEA containing 43.6% oxygen at the OEA flux of 5.06 × 10^?4 cm³ (STP)/s cm² with a good performance stability. © 1995 John Wiley & Sons, Inc.     

纳米尼龙/聚苯乙烯/马来酸酐复合材料性能的研究

通过马来酸酐(MAH)对聚苯乙烯(PS)接枝改性制得聚苯乙烯接枝马来酸酐共聚物(PS-g-MAH),然后将PS-g-MAH与纳米尼龙(NYC)按不同比例共混,制得纳米尼龙/聚苯乙烯接枝马来酸酐复合材料(NYC/PS-g-MAH),对其结构、力学性能及阻燃性能进行了表征分析。结果表明:NYC/PS-g-MAH复合材料的力学强度和阻燃性能有所提升,其抗冲击强度最大可达到6.0×102kJ/m2,拉强度最大可达到72.5 MPa,氧指数可以达到23%。     

Air separation characteristics with liquid crystalline alkyl cellulose blend thin-film composite membranes

Composite membranes were made of liquid crystalline triheptyl cellulose (THC)/ethyl cellulose (EC) blends as dense thin films and poly(ether sulfone) (PES) or polysulfone (PSF) as porous support layer. The effects of the composite membrane composition and operating conditions on the air separation characteristics of oxygenenriched air (OEA) permeating through the membranes were studied using a constant pressure-variable volume method. The flux (OEA) through the membranes decreases slightly and the oxygen concentration in the OEA permeated increases with increasing THC content in the thin film from 4 to 15 wt.-%. The OEA flux increases significantly with decreasing thin-film thickness or increasing operating temperature and transmembrane pressure difference. The oxygen concentration in the OEA increases with increasing the thin-film thickness or the pressure difference but decreases slightly with increasing the operating temperature. There is no regular variation in the air separation properties by changing the support from PES to PSF. In long-term tests, the air separation properties remained almost constant for as long as 800 h. An OEA flux of 1.0–1.9·10^-3 cm³ (STP)/s·cm² containing 34.8–39.4 vol.-% oxygen can be attained at 30–55°C and 0.41–0.49 MPa pressure difference in a single pass through the membranes. The OEA flux is much higher for the thin-film composite membranes than for the homogeneous dense membranes made of the same materials.     

Al（OH）3／胺取代三嗪磷酸盐对HDPE阻燃性能的影响水

先以三聚氯氰和甲胺溶液为原料,合成了2,4,6-三甲胺基-1,3,5-均三嗪（TMM）,再以TMM和磷酸合成了2,4,6-三甲胺基-1,3,5．均三嗪磷酸盐（TP）,产率分别为90．3％和72．3％,采用FT—IR和TGA对合成产物进行了表征。研究了氢氧化铝（Al（OH）3）与TP并用对HDPE阻燃性能的影响。结果表明,并用TP和Al（OH）,提高了HDPE的氧指数,两者显示出阻燃协同效应。锥形量热结果表明,并用10％TP和40％Al（OH）3可使阻燃HDPE的最大热释放速率降低至348．47KW／m^2,最大烟释放速率降低至0．032m^2／s,分别比纯HDPE降低了50．6％和70．9％。     

Actual air separation through poly(aniline‐co‐toluidine)/ethylcellulose blend thin‐film composite membranes

Several multilayer thin‐film composite membranes were fabricated of ethylcellulose (EC) and poly(aniline‐co‐ortho‐toluidine) or poly(ortho‐toluidine) blend as selective thin films and three ultrafiltration membranes with a 10‐ to 45‐nm pore size and 100‐ to 200‐μm thickness as porous supports. The relationships between the actual air‐separation performance through the composite membranes and layer number, composition, casting solution concentration of the thin selective film are discussed. The oxygen‐enriched air (OEA) flux through the composite membranes increases steadily with increasing operational temperature and pressure. The oxygen concentration enriched by the composite membranes appears to decrease with operating temperature, but increases with operating pressure. The actual air‐separation property through the composite membranes seems to remain nearly constant for at least 320 days. The respective highest OEA flux, oxygen flux, and oxygen concentration, respectively, were found to be 4.78 × 10⁻⁵ cm³ (STP)/s · cm², 2.2 × 10⁻⁵ cm³ (STP)/s · cm², and 46% across EC/poly(o‐toluidine) (80/20) blend monolayer thin‐film composite membranes in a single step at 20°C and 650 kPa operating pressure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 458–463, 2000     

丙纶无纺布的网孔结构和水蒸气透过性研究

系统研究了不同克重丙纶无纺布的网孔结构和水蒸气透过性(MVTR),结果表明:采用光学显微镜研究丙纶无纺布丝网形态和网孔结构是完全可行的;随着无纺布克重的增加,网孔结构变密,孔隙率变小,透气性变差;当其克重介于25～45g/m2范围时,MVTR达到2100g/(m2.24h);采用丙纶无纺布制备的一次性吸汗巾的MVTR达到2080g/(m2.24h),透气性和舒适性优于聚乙烯透气膜,具有良好的性价比。     

以植物油做膜液的支撑液膜法处理染料废水的研究

以天然植物油为膜液,含聚四氟乙烯涂层的聚丙烯平板膜（PPsT）作为支撑膜,研究了支撑液膜（SLM）系统去除和回收水溶液中分散染料阳离子红4G的性能及影响因素,并确定了最佳实验条件：料液pH值11．0±0．1,脱除液：1．0g／LH2SO4,搅拌速度：350rpm．膜液：棕榈油,脱除时间：7h。去除率随料液初始浓度的增大（〉100mg／L）而增大,但通量J不变（在液膜稳定的情况下）。在最佳条件下,100mg／L的染料溶液其去除率达到94．1％。利用扫描电子显微镜（SEM）和能量弥散Z射线分析仪（EDX）对该液膜的稳定性进行了研究。结果表明：染料去除率从第1d的95．2％下降到第5d的56．3％,通量J从17．2×10^-6g／m^2·s降到8．1×10^-6g／m^2S。5d后液膜的损失量为20．5％。