Current state-of-the-art lab-scale methods for fabricating superhydrophobic membranes for membrane distillation often involve complex surface modifications or the use of nanomaterials. However, these methods are difficult to scale up.
This technology relates to a pure rheological spray-assisted non-solvent induced phase separation (SANIPS) approach to fabricate superhydrophobic polyvinylidene fluoride (PVDF) membranes. The resulting membranes have high porosity, superhydrophobicity, high liquid entry pressure, and hierarchical micro/nanostructures. They can also be easily scaled up.
The spraying step caused local distortion of the membrane surface, which induced a two-stage phase inversion. This led to the formation of multilevel polymeric crystal structures. The morphological structures and other membrane properties (e.g., mechanical strength and liquid entry pressure) could be tuned by applying spraying materials with different physicochemical properties.
This facile fabrication method will pave the way for the large-scale production of superhydrophobic membranes for membrane distillation.
Flat sheet membrane:
Membrane distillation (MD) is a membrane technology that uses the vapor pressure gradient across a porous hydrophobic membrane to separate water from other components.
MD offers several advantages over other membrane separation processes, including:
These advantages have led to promising results in MD processes for zero-liquid discharge, desalination, desalination brine treatment, and many other wastewater treatment applications.
However, the commercialization of MD has been constrained by the lack of commercially available high-performance MD membranes and high energy consumption.
This work addresses the lack of commercially available high-performance MD membranes and has the potential to be the next workhorse of the water industry.