2.4. Measurement of Liquid Entry Pressure

An in-house apparatus was used to measure the liquid entry pressure (LEP) of the fabricated membranes [11,40]. As shown in Figure 1, the apparatus consists of an LEP chamber, a pressure gauge, a high-pressure N₂ gas cylinder, and a pipe. To begin, 50 mL DI water was poured into the chamber and a dried membrane sample was mounted. The chamber was then pressurized from its bottom using the N₂ gas cylinder connected with the pipe. The pressure was controlled using the gauge to determine the minimum pressure that resulted in the first water drop on the membrane surface. The LEP measurements were repeated three times and the average and the standard deviation were recorded.

Schematic drawing of LEP apparatus.