Pervaporative Separation of Methanol/Methyl tert-butyl...

1. Introduction Separation or organic/organic mixtures using pervaporation process has become a prime alternative and is extensively studied particularly in the chemical and petrochemical industries due to the process versatility. One of the classic example of its application is the separation of methanol (MeOH) from methyl tert-butyl ether (MTBE) in the production of octane enhancers for fuel blend, which has already been commercialized using cellulose acetate by Air Products [1, 2]. Since then, efforts have been devoted to producing the optimal membrane material for pervaporation separation of alcohol/ether mixtures [1, 2, 3]. In the similar attempt conducted by Kim et al., [2], pervaporative separation of this azeotropic mixtures†¦show more content†¦CS concentration was fixed at 2.0 wt% and dissolved in 1 wt% acetic acid. Blends of CS and SA were casted onto the porous support to form composite membranes and air dried. 2.2 Membrane characterization 2.2.1 SEM analysis. The morphology of the composite membranes were determined by using Phillips XL -40 Scanning Electron Microscope (SEM) at 10 kV accelerating voltage. The membranes were sputter-coated with gold before analysis. 2.2.2 Swelling Experiments. The pre-weighed composite membranes were immersed in a liquid sorbate of known composition of MTBE/MeOH in a closed bottle at room temperature for 24 hours for an equilibrium swelling. The swollen composite membranes were weighed after excess liquid was blotted with filter paper. The amount of sorbed liquid in the composite membranes was expressed as degree of swelling (DS%) which was calculated according to Eq. 1, DS%= (W_s-W_d)/W_d . (1) where W_s and W_d are the weight of swollen and dried samples, respectively. 2.3 Pervaporation experiments. The schematic representation of pervaporation of MeOH/MTBE mixtures is shown in Figure 1, which operated in batch mode. The effective membrane area was 56.745 cm2. Permeate was collected in the flask attached to glass cold trap and its composition was analyzed using