Filiz Ugur Nigiz

Pervaporation of ethanol/water mixtures by zeolite filled sodium alginate membrane

Abstract For a few decades, pervaporation (PV) has been considered as an energy saving, environmentally friendly and cost effective separation technique which separates close boiling point, azeotropic and thermally sensitive components. It is clearly well known that the PV has significant advantages in azeotropic mixtures separation where distillation needs an entrain solvent which must be removed in the following steps. The most important part of PV is the selection of the appropriate membrane. The inadequate selectivity and low flux values limited the expansion of this process. It is always assumed that efficient pervaporation means a membrane with good permeability and selectivity. In this work, sodium alginate (NaAlg) was used as the membrane material. Pristine NaAlg and zeolite 4A filled NaAlg mixed matrix membranes (MMMs) have been prepared by solution casting evaporation and cross-linking method. Phosphoric acid (PA) was used as the cross-linking agent. The morphologies of the membranes were studie...

Pervaporative desalination of seawater by using composite and blended poly(vinyl alcohol) membranes

In this study, pervaporative separation capability of poly(vinyl alcohol) (PVA) based different membranes were investigated. Pristine, zeolite-loaded and blended PVA membranes were prepared by solution-casting and cross-linking method. Zeolite 3A was used to make PVA more stable and durable during the different operation conditions. Sodium alginate has strong hydrophilic bond structure so it was used to enhance water flux. Flux and salt retention values were investigated over temperature range of 293‐313 K. Pervaporation performances were evaluated as function of flux and salt retention. At low temperature, ion passage was prevented and 100% salt retention was achieved by all membrane types. As the temperature increased from 293 to 318 K, salt retention dramatically decreased. Increasing zeolite loading positively affected the water flux. Also, blended membrane gave better flux results than pristine PVA.

Anhydrous fuel ethanol production by a combined hydrophobic–hydrophilic pervaporation system

ABSTRACT In this study, a hybrid bioethanol production and purification system was designed and operated at different operation conditions. In the first stage, dilute ethanol (3 wt%) was produced by fermentation and concentrated to 80 wt% ethanol–water mixture by means of poly(dimethylsiloxane) membrane. In the second stage, residual water was purified to approximately 99% water content by using carboxymethyl cellulose membrane. The first stage is a fermentor, so the temperature was kept stable at 25°C. Effects of the operation variables such as temperature and concentration of the mixture on membrane separation performance were evaluated.

Bioethanol Production from Molasses by Pervaporation Membrane Bioreactor

Bioethanol is a clean and green energy source that can be produced from fermented biomass. Environmental regulations require bioethanol to be blended with gasoline. Thus researchers and producers accelerate ethanol production from biobased sources and waste. There are many bioethanol production plants all over the world. Ethanol production steps consist of pretreatment, fermentation, and deep purification steps. The impurities in fuel ethanol should be below the limit values. Therefore, some specific purification techniques are required. The major production drawback is the complicated separation step that covers a very large portion of the production cost. Hence researchers place great emphasis on the separation step. For some time, the separation–fermentation hybrid system has garnered much attention owing to its economical and environmental features. The pervaporation membrane bioreactor (PVMBR) is a pervaporation-coupled fermentation hybrid process. In PVMBR, ethanol is selectively removed from the fermentation broth.

Novel environmental friendly process for reducing the sulphur level in fuel: pervaporation

Pervaporation (PV) is an alternative membrane-based process for removal of sulphuric components with low energy consumption. In PV, selective removal bases on the concentration difference between two sides of membrane. In sulphur removal process hydrophobic membranes are generally used due to the flexible chain structure. If the solution parameters and polarities of membranes are close to the sulphur components then hydrophilic membranes are preferred. In this study, pristine and wt. 3%, 5% and 10% of poly(oligosilsesquioxanes) (POSS) loading poly(dimethyl siloxane) (PDMS) membranes have been prepared for pervaporation experiment. Sorption and desorption experiments have been performed at room temperature to determine the swelling characters and sorption selectivity values of the membranes with respect to the sulphur concentration.

Clean Technology for Volatile Organic Compound Removal from Wastewater

Volatile organic compounds (VOCs) are the main contaminants in industrial wastewater. It is well known that the presence of these compounds in water—even if they are at low concentration—causes a carcinogenic effect. At industrial scale, removal of these compounds is possible commercially. Membrane-based pervaporation (PV) promises to be clean energy system when it is accompanied with the membrane which has high affinity to VOCs. Compared to the other methods, PV offers some advantages. It is energy intensive, cost effective, clean, and modular technology. In this work, pristine and 20 wt.% and 30 % of ZSM-5-filled zeolite-loaded composite polydimethylsiloxane membranes are prepared and they are employed in pervaporation process to separate toluene from toluene–water mixtures. PV performance is evaluated as a function of flux and enrichment factor. ZSM-5 zeolite is selected as inorganic particle due to the highly hydrophobic characteristic. Pervaporation experiments are carried out at room temperature.