Partial wetting in porous catalysts: wettability and wetting e&ciency

Qualitative changes in the local (pore level) wetting e&ciency of a porous catalyst as a function of catalyst wettability are proposed based on monitoring the 1-D motion of the solid-liquid-gas contact line. As catalyst wettability is increased, the resulting wetting e&ciency is likely to show two distinct transitions viz., (1) a sudden decrease that is inspired by coalescence of neighboring rivulets and, (2) a sudden increase that is inspired by porous nature of the catalyst. As catalyst wettability decreases, the wetting e&ciency is likely to decrease in the beginning but can then be held constant due to pinning or holding of the retracting contact line by liquid-5lled pores. This will result in comparatively much higher wetting efficiencies. It is further proposed that under favorable circumstances this pinning can disappear and will, thus, allow the contact line to retract and wetting e&ciency to decrease. In the end, the e8ect of catalyst geometry on the relation between wetting e&ciency and wettability is presented.