Polyamide-based mixed matrix membrane for oil-water separation

A mixed matrix membrane, comprising:

• a polymer comprising reacted units of a 3,5-diaminobenzoic acid and isophthaloyl chloride in a molar ratio of 5:1 to 1:5;
• and
• a polyvinylidene fluoride,
• wherein a weight ratio of the polymer to the polyvinylidene fluoride is from 1:1 to 1:20 based on a total weight of the polymer and the polyvinylidene fluoride,
• wherein the polymer and the polyvinylidene fluoride form a trilayer structure of horizontal layers with a first porous outer layer of the polyvinylidene fluoride and a second porous outer layer covering a porous inner layer of the polymer,
• wherein the first porous outer layer has a pore size with a longest dimension of 3 to 30 μm,
• wherein the second porous outer layer has a pore size with a longest dimension of 1 to 10 μm,
• wherein the porous inner layer has void spaces having an average longest dimension of from 20 to 500 μm,
• wherein amine groups and carboxyl groups in the polymer and fluorine in the polyvinylidene fluoride form hydrogen bonds between the horizontal layers.