A mixed matrix membrane that includes polyvinylidene fluoride and TiN nanoparticles may be useful solar-driven surface heating membrane distillation. The plasmonic character of the TiN nanoparticles may locally heat the membrane when exposed to sunlight, which increases the distillation flux across the membrane. Said distillation methods may be particularly useful for treating laundry wastewater to collect distilled water with a reduced concentration of chemical oxygen demand, a reduced concentration of total dissolved solids, and a reduce conductivity. The distilled water may be repurposed for a variety of purposes including agricultural irrigation with significant less impact on the aquatic ecosystem compared to the laundry wastewater.

The present invention relates to a method for preparing a porous polymer film having a controlled pore depth, and a porous polymer film prepared thereby. A method for preparing a porous polymer film according to the present invention allows the pore depth of a porous film to be controlled simply and at a low cost, and thus allows adjustment of the light reflectance of the prepared film. A large-area film can be prepared by means of a simple method and thus can be applied to various industry fields. Films having different reflectance can be prepared and thus can be applied as low-reflection and high-reflection films for solar cells, and also as a low-reflection or high-reflection thin polymer film in the construction field or material and equipment field.