PDMS/PVDF composite pervaporation membrane for the separation of dimethyl carbonate from a methanol solution

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. By controlling the fabricating parameters such as the concentration of the casting membrane solution, composite membranes with different thicknesses from 3 to 160μm were fabricated. When the composite membrane is defect-free, the separation factor is independent of its thickness. The composite membrane with a thickness of 6μm exhibited a separation factor of 3.95 and a normalized total flux of 0.4872kg/m²h in the pervaporation of 28wt% DMC-methanol mixture at 40°C. In addition, the membrane swelling effects, pervaporation performance, and stability were investigated. The results of the PDMS composite membrane exhibited higher and more stable performance in separating DMC from the methanol solution. The PDMS composite membrane can be a suitable PV membrane to separate DMC from a methanol solution.