Action Effect Result
Using the large seeds as the bottom layer Prevents the infiltration of seeds into the support pores Reduces the effective membrane thickness Higher permeance
Forms more inter-crystalline gaps in the bottom layer Decreases the density of the zeolite layer close to the support Higher permeance
Seed size change at the bottom layer mostly influences the membrane permeance Seed size change at the bottom layer mostly influences the membrane permeance Seed size change at the bottom layer mostly influences the membrane permeance Seed size change at the bottom layer mostly influences the membrane permeance
Using the small seeds as the top layer Small seeds from top layer penetrate into the pores of bottom layer Eliminates the defects and non-zeolitic pores Higher selectivity
Forms a uniform thin seed layer at the top Creates a continuous thin zeolite layer with smooth surface Higher selectivity
Increases the grow rate of small seeds on top which are in contact with the synthesis solution Forms a denser zeolite layer on top Higher selectivity
Seed size change at the top layer mostly influences the membrane selectivity Seed size change at the top layer mostly influences the membrane selectivity Seed size change at the top layer mostly influences the membrane selectivity Seed size change at the top layer mostly influences the membrane selectivity