Pervaporation Performance of Ag-PVA Nanocomposite Membranes: Effect of Operating Temperature

The features of pervaporation are continuously improved with the production of more and more efficient membranes. In our present study, silver nanoparticles are in-situ generated in a poly (vinyl alcohol) using solution-casting in order to enhance its capability for pervaporation. The membrane is tested on the case study of ethanol dehydration by pervaporation. Effect of silver content on the pervaporation separation index and the enrichment factor of the membrane at 15 % mass water at 40 °C are reported. Pervaporation data for nanocomposite membranes show around 100 % increase in the water permeance values while the intrinsic selectivity decreases that is typical for pervaporation membranes. The water permeances of original crosslinked PVA membrane and the 2.5 % silver loaded PVA membrane are 26.65 and 70.45 (g/m2.kPa.h), respectively. The values of total flux are closely related to water flux, showing that membranes could be successfully assigned to separate water from ethanol even at the azeotropic point. The influence of temperature on the efficiency of the pervaporation process, permeation parameter and diffusion coefficient of the feed component is also discussed. The negative heat of sorption (∆Hs) values calculated on the basis of the estimated Arrhenius activation energy values indicates that the sorption process is controlled by Langmuir's mode. Our results show that the 0.5 mass% silver loaded poly (vinyl alcohol) membrane exhibits excellent PV performance

Development of Hybrid Organophilic Pervaporation and Distillation Method for Separation of Mixture Containing Heterogeneous Azeotropic

The study is motivated by the industrial separation problem in the fine chemical and pharmaceutical industry, that is isobutanol removal from process wastewater. There are several options for separating the isobutanolwater system. When separating on an industrial scale, it is essential that the most suitable alternative is implemented. The classical method of isobutanol-water separation is distillation. However, since the mixture forms a heteroazeotrope, only an azeotrope composition can be achieved with traditional distillation. Azeotropic distillation is a solution, the alternative is membrane separation, including pervaporation. The aim of this study is to investigate and optimize hybrid organophilic pervaporation and distillation processes for the separation of the isobutanol-water mixture. The examination is carried out in professional flowsheet simulator environment with user-added organophilic pervaporation membrane modules, phase separator and distillation column. Applying this new process, it is possible to obtain 99.9 weight% alcohol and water product from the initial 7 weight% isobutanol - 93 weight% water mixture

Modelling of Hybrid Method for VOC Removal from Process Wastewater: Distillation and Hydrophilic Pervaporation

The study is motivated by the industrial problem from pharmaceutical industry, which is ethanol and methanol removal from process wastewater. To complete this goal hybrid method is investigated and optimized. Two distillation columns are sufficient for separation of alcohol-water mixture. Suitable water can be purified as bottom product of first column. Ethanol and methanol purification is achieved with combination of second distillation column and pervaporation. The target of this research is to rigorously model and optimize the separation of water-ethanol-methanol ternary mixture in professional flowsheet simulator environment. The minimal sufficient membrane transfers area and number of minimal theoretical stages of the columns are determined. Cost estimation is also investigated according to Douglas methodology. Considering the simulation and economic results it can be determined that, the hybrid configuration is suitable for separation of ternary mixture in 99.5 weight percent purity