Search

Membrane distillation (MD) is a thermal-driven membrane separation process which recently garners interest from academic and industry due to its low energy requirements and the ability to integrate with renewable energy. In this work, two different additives, i.e. polyethersulfone (PES) and ethylene glycol (EG), were added into dope solutions consisting of polyvinylidene fluoride (PVDF) and 1-methyl-2-pyrrolidone (NMP) to prepare membranes for MD applications. The membranes were characterized with respect to thickness, pore size, porosity, and water contact angle using scanning electron microscope and water contact goniometer. Compared with the membranes made from pure PVDF and PVDF–EG system, it is found that PVDF–EG–PES membrane displayed improved characteristics i.e. having optimum porosity, large pore size, and thin membrane thickness coupled with finger-like structure extended from both inner and outer layers of the membrane. In addition to this, the permeate flux of PVDF–EG–PES membrane during MD application was also reported to be the highest among all the membranes studied when tested under same process conditions. With respect to membrane performance stability, the results showed that PVDF–EG–PES membrane could achieve a very consistent permeate flux while maintaining high NaCl rejection throughout 20 h operation, indicating the potential of this membrane in MD process. [ABSTRACT FROM PUBLISHER]

Abstract: In this study, the polyvinylidene fluoride (PVDF)–Titanium dioxide (TiO2) mixed-matrix membranes were prepared via phase inversion technique. The properties of PVDF–TiO2 mixed-matrix membranes were characterized based on pore size distribution, membrane porosity, field emission scanning electron microscope (FESEM) and photocatalytic behavior. The hydrophilicity of the mixed-matrix membrane was enhanced and resulted in the improved pure water permeability (392.81±10.93l/m2 hbar) compared to that 76.99±4.87l/m2 hbar of the neat membrane. The neat and mixed-matrix membranes were further investigated in terms of filtration, adsorption and UV-cleaning properties based on methylene blue (MB) solution. Mixed-matrix membranes showed excellent removal efficiency (∼99%) when sodium dodecyl sulfate (SDS) was introduced into the MB feed solution. The produced mixed-matrix membrane shows some slight photocatalytic properties improvement as FTIR results reviewed that the cleavage of h name="dbnd" />N bonding due to MB adsorption reduced more significantly with the presence of TiO2 NPs and ultraviolet (UV) light irradiation. The UV-cleaning properties of the mixed-matrix membrane were further proved by the 100% flux recovery ratios (FRRs) for mixed-matrix membrane, suggesting that the embedded TiO2 NPs was photocatalytically active and able to degrade the adsorbed MB in the membrane. [Copyright &y& Elsevier]