Adsorption of Ni(SO4) on Malaysian rubber-wood ash

The possible use of wood ash as an adsorbent of nickel sulphate from dilute solutions and the effect of operating parameters were investigated in this study. The rate constants of adsorption were determined at different concentrations and temperatures. The applicability of the first-order reversible equation and an empirical kinetic model were tested to understand the kinetics of nickel sulphate removal at different concentrations. Pore diffusion was found as the rate-controlling step. The Langmuir and Freundlich isotherms were applied to find out the adsorption parameters. The activation energy of adsorption was -11.54 kJ mol-1. The value of the enthalpy change was ?H=-10.35 kcal mol-1.

A spectroscopic study of the chemistry and reactivity of SO2 on Pt{111}: Reactions with O-2, CO and C3H6

The chemisorption and reactivity of SO2 on Pt{111} have been studied by HREELS, XPS, NEXAFS and temperature-programmed desorption. At 160 K SO2 adsorbs intact at high coverages, with eta(2) S-O coordination to the surface. On annealing to 270 K, NEXAFS indicates the SO2 molecular plane essentially perpendicular to the surface. Preadsorbed O-a reacts with SO2 to yield adsorbed SO4, identified as the key surface species responsible for SO2-promoted catalytic alkane oxidation. Coadsorbed CO or propene efficiently reduce SO2 overlayers to deposit S-a, and the implications of this for catalytic systems are discussed.