Autopore 4

To measure the porosity of the Lunaria septa, mercury porosimetry was performed using an AutoPore IV porosimeter (Micromeritics, GA) with a pressure range of 0 to 33,000 psi. From the raw data of intruded volume versus pressure, differential intrusion as a function of pore size was calculated using the Washburn equation (assuming contact angle θ = 130° and surface tension γ = 0.485 N/m). To ensure enough material in the penetrometer, three septa were used for each porosity measurement. In total, four measurements were performed for statistical reliability and repeatability of the porosity measurement.

The pore characteristics of the plugs were analyzed using a Micromeritics AutoPore IV mercury porosimeter, which measured the pore size distribution, porosity, permeability, and grain density. The analysis was carried out on small subvolumes of the plug measuring 0.5 cm × 0.5 cm x 0.3 cm (see Fig. 1B), and pore pressure ranges from 0.5 to 40,000 psi were used. The Washburn equation was employed to calculate the pore size distribution, assuming cylindrical pores. The equation converted the imposed pressure $p$ into the corresponding pore radius $r$ , using parameters such as the mercury contact angle $\theta$ (130°) and surface tension $\gamma$ (485 mNm-1) (Equation 2) [42 ]. $p=\frac{2\gamma \mathit{cos}\mathit{cos}\theta }{r}$

The surface and cross-sectional morphology of the fabricated ceramic hollow fibre membranes (KHFMs) were measured using Scanning Electron Microscopy (SEM) (TM 3000, Hitachi). The contact angle of the ceramic hollow fibre membrane was measured at the surface before and after hydrophobization by the sessile drop technique using a goniometer (Model: OCA 15EC, Dataphysics). Mercury intrusion porosimetry (MIP, AutoPore IV, Micromeritics, USA) was used to measure the porosity and pore size distribution of the KHFMs prepared at different sintering temperatures and addition of pore agents. The KHFMs were broken into pieces and transferred to the 5 cm³ penetrometer sample holder (Micrometeritics, USA) which was then pressurized from 38.6 to 4.2 × 10⁶ mbar for mercury intrusion.³¹ In this study, liquid entry pressure (LEPw) was used to measure the wettability properties of the grafted ceramic hollow fibre membranes. Distilled water flowed into the lumen side of the hollow fibre membranes using a diaphragm pump. The pressure was slowly increased, at 0.5 bar intervals, and the pressure at which the first water droplets appeared on the shell side surface of the hollow fibre was recorded as the LEPw.^{13,14 (link)}