Abstract

The kinetics of adsorption of sodium-palmitate and sodium-laurate onto galena, hematite and cassiterite in aqueous media was investigated at various concentrations, times and temperatures. Experimental results were analysed using the pseudo-first and pseudo-second order kinetic models. The pseudo-first order model with higher correlation coefficient values described the adsorption kinetics better than the pseudo-second order model. The rate constant from the pseudo-first order model [0.109 min^-1 for galena, 0.102 min^-1 for hematite, 0.085 min^-1 for cassiterite (in the sodium-palmitate adsorption) and 0.127 min^-1 for galena, 0.109 min^-1 for hematite, 0.095 min^-1 for cassiterite (in the sodium-laurate adsorption) at 29^oC] show these rates in the order: galena > hematite > cassiterite for the adsorbents; and sodium-laurate > sodium-palmitate for the adsorbates. Some kinetic parameters were computed and the values obtained indicate that the adsorption processes occurred at reasonable rate, low temperature and low energy suggesting physical adsorption as the dominant process.

Key words: Kinetics, adsorption, soap, collector reagent, pseudo-first order.