Pertraction performance of phenol through PDMS/PVDF composite membrane in the membrane aromatic recovery system (MARS)

Pertraction properties of phenol from aqueous solution through a plate composite membrane (poly (dimethylsiloxane) (PDMS)/polyvinylidene fluoride (PVDF)) in the membrane aromatic recovery system (MARS) were investigated systematically. The effects of liquid flow status, system temperature, feed concentration and pressure on the overall mass transfer coefficient (Kov), and the permeability for phenol through the membrane were also discussed. The feed-side liquid boundary layer mass transfer coefficient was proportional to Re0.46, membrane mass transfer coefficient was 15.0×10−7 m s−1, which exhibited five times higher than that of tubular silicone rubber membrane (3.5×10−7 m s−1), and possessed higher mass flux (2.38×10−2 kg m−2 h−1) and lower activation energy of permeation (9.7 kJ mol−1). Whereas, the permeability (5.9×10–12 m2 s−1) and diffusion coefficients (2.4×10–11 m2 s−1) of phenol were lower than those of nonporous silicone rubber. Kov increased with the rise of feed concentration and finally reaches a stable level (5.0–15.0 g l−1). The diffusivity of phenol in the membrane was decreased with pressure. The membrane mass transfer resistance was found to be the rate controlling step in the transport process of phenol.

► Mass transfer process of phenol across PDMS/PVDF composite membrane was investigated.
► A new model was developed to describe liquid boundary layer mass transfer in MARS.
► PDMS/PVDF composite membrane exhibited km (1.5×10−6 m s−1) five times higher than that of tubular silicone rubber.