ADSORPTION OF THIOPHENE ON NICKEL ALUMINA CATALYSTS

An experimental and modeling study of the adsorption of thiophene on nickel/alumina has been made. Adsorption studies were performed in a microbalance flow reactor with a 1000 ppm thiophene/H2mixture at ambient temperatures and pressures. The catalysts used had compositions of 10,15, and 20 wt % Ni supported on γ-AL2O3. Experimental results conformed to a model that consists of a pore-diffusion process in series with two parallel or series rate processes for adsorption: one via a five-site mechanism (coplanar with the surface) and the other via a two-site mechanism (perpendicular to the surface). Kinetic parameters in the rate equations were determined directly from the experiments. Additional parameters such as the effective diffusivity and the mass-transfer coefficient were calculated from appropriate correlations. The fractions of the surface corresponding to two-site and five-site adsorption were calculated from the observed saturation stoichiometry. © 1990, American Chemical Society. All rights reserved.