Although it would be expected that more sulfide layers would
form under higher sulfur loadings, no bulk sulfide was detected
even after full deactivation of the catalyst, indicating an equilibrium
adsorption of sulfur on the surface of the Ni particles. The
yield of sulfur generally followed the same deactivation trend as
that of hydrogen and unreacted thiophene was seen in the liquid
effluent from experiments with more highly deactivated catalyst,
suggesting no further adsorption of sulfur after saturation. This also
suggests a solid diffusion-limited process.