PDMS膜

Abstract(#br)Implementation of try and error method for membrane preparation procedures is a time and cost consuming technique. This study tries to present a novel idea to make membrane preparation procedure heuristic. Applying this method, helps researchers to predict performance of a membrane prior to its preparation . At first, a number of membranes are prepared and characterized. Then, their measured separation properties are used for prediction of performance of a membrane before its preparation.

Abstract(#br)Vapor permeation through dense membrane is regarded as an effectively way to separate volatile organic compounds (VOC) from industrial gas stream. This study proposes a new method to get the solubility and diffusivity of pure VOC vapor in dense membrane. C 5 H 12 , C 6 H 14 and C 7 H 16 were selected as sample VOC components to conduct newly developed sorption experiment with polydimethylsiloxane (PDMS) membrane.

Abstract(#br)In this paper, polydimethylsiloxane (PDMS) composite membranes that were supported using polyvinylidene fluoride (PVDF) microfiltration membrane were developed for the pervaporation (PV) of dimethyl carbonate (DMC) from a methanol solution. Experimental studies on the solubility and the diffusivity of pure DMC and methanol in the membrane were first measured. Higher DMC uptake indicates that the sorption step is the rate-limiting step in the selective transport through the membrane.

Abstract(#br)This study aimed to improve surface polarity of polydimethylsiloxane (PDMS) membranes and provide surface active sites which were easy to react with other chemicals. 3-Aminopropyltriethoxysilane (APTES) containing an amino group was introduced into a PDMS membrane by crosslinking to prepare polyacrylonitrile hollow fiber-supported PDMS membranes with an amino-functionalized surface. Fourier transform infrared and X-ray photoelectron spectroscopic analyses proved the existence of APTES and its amino group in the PDMS membrane.

The nonspecific adsorption of proteins and bacteria on the surface of polydimethylsiloxane (PDMS) had been a serious concern in a wide range of applications, such as medical devices. In order to improve the anti-adhesive and antibacterial capability, bare silver nanoparticles (AgNPs, ~15 nm) were generated in-situ on their surface without extra reducing and stabilizing agents.

Abstract(#br)The cost of polymer membranes significantly affects their industrial applications, which is inversely proportional to their thickness. Hence, to economically realize the industrial applications of polymer membranes, their thickness should be reduced. In this work, a facile and scalable coating method was used to fabricate thin pervaporation composite membranes. The viscosity of the membrane solution and the hydrodynamic diameter of the polymer coil in heptane were optimized.

高能源需求、竞争激烈的燃料价格以及对环境友好工艺的需要，导致了酒精工业的不断发展。渗透汽化被看作是一种分离过程，能耗低，在乙醇的发酵脱水方面具有很高的应用潜力。本工作给出了渗透汽化回收乙醇的实验和部分通量的半经验模型。在乙醇进料浓度为4 ~ 37 mM ( 1 ~ 9 wt % )、温度为34 ~ 50 μ mol / L ~ ( - 1 )、渗透通量为15.6 ~ 68.6 mol · m ~ ( - 1 ) ~ ( - 1 ) ( 289 ~ 1565 ) g · m ~ ( - 1 ) ~ ( - 2 ) h ~ ( - 1 ) )、分离因子为3.4 ~ 6.4、乙醇摩尔分数为16 ~ 171 mM ( 4 ~ 35 wt % )的条件下，采用商业聚二甲基硅氧烷( PDMS )膜，获得了总渗透通量为15.6 ~ 68.6 mol · m ~ ( - 1 ) ( 289 ~ 1565 ) g · m ~ ( - 2 ) · h ~ ( - 1 )，分离因子为3.4 ~ 6.4。从实验数据出发，综合考虑温度和进料组成的影响，以及表观活化能的行为，建立了描述部分渗透通量行为的半经验模型。因此，所得到的模型显示出一种修正的Arrhenius型行为，能够高精度地计算部分渗透通量。此外，模型在乙醇回收、乙醇和丁醇脱水等过程中显示了通用性。

高能源需求、竞争激烈的燃料价格以及对环境友好工艺的需要，导致了酒精工业的不断发展。渗透汽化被看作是一种分离过程，能耗低，在乙醇的发酵脱水方面具有很高的应用潜力。本工作给出了渗透汽化回收乙醇的实验和部分通量的半经验模型。在乙醇进料浓度为4 ~ 37 mM ( 1 ~ 9 wt % )、温度为34 ~ 50 μ mol / L的PDMS膜上，总渗透通量为15.6 ~ 68.6 mol m-2 h-1 ( 289 ~ 1565 g m-2 h-1 )，分离因子为3.4 ~ 6.4，乙醇摩尔分数为16 ~ 171 mM ( 4 ~ 35 wt % )。从实验数据出发，综合考虑温度和进料组成的影响，以及表观活化能的行为，建立了描述部分渗透通量行为的半经验模型。因此，所得到的模型显示出一种修正的Arrhenius型行为，能够高精度地计算部分渗透通量。此外，模型在乙醇回收、乙醇和丁醇脱水等过程中显示了通用性。

聚合物膜的成本显著影响其工业应用，其厚度与成本成反比。因此，为了经济地实现聚合物膜的工业应用，必须减小聚合物膜的厚度。本工作采用一种简便、可扩展的涂层方法制备了薄的渗透汽化复合膜。优化了膜溶液的粘度和聚合物卷在庚烷中的流体力学直径。可得到厚度低至700 nm的聚二甲基硅氧烷/聚四氟乙烯复合膜。复合膜表面疏水性几乎不变，在40  ℃分离5  wt %乙醇溶液时，分离因子保持8.6，通量高达2.4   kg / ( m2·h )。研究了进料压力、进料温度、水蒸气透过率和底物对其性能的影响。结果表明，膜液粘度过低或过高都不适合无缺陷膜的形成。这也说明本研究开发的采用最佳膜液黏度的镀膜方法是大规模制备亚微米厚膜的有效途径。