The adsorption of surfactant on inks related to paper recycling

Abstract

Adsorption of surfactant at the solid-aqueous solution interface has been extensively studied to understand interactions between the surfactant and the solid surface. In the present study, the influence of pH and calcium concentration on the adsorption of sodium dodecyl sulfate (SDS) onto carbon black surface was investigated. Measurements of electrokinetic potential of suspensions of SDS-adsorbed carbon black particles were combined in order to monitor the variation in potential as a function of adsorption. The results showed that the adsorption of SDS onto carbon black gave strong interactions between the hydrophobic tail group of SDS and the carbon surface. The presumed configuration of the adsorbed SDS molecule was tail-down and/or laying down orientation. The effect of pH was not found to be significant on the adsorption of SDS while the addition of a calcium salt enhanced SDS adsorption.