Abstract:
Flotation deinking is a common method used to remove ink from paper in paper recycling processes. The mechanism of flotation was predicted by studying the interaction of an anionic surfactant (sodium dodecyl sulfate (SDS) or sulfate) with paper fiber. The effect of calcium concentration was also studied. The pH values used in this study were 7 and 9. Experimental data from adsorption isotherms indicated that calcium ions adsorbed on negatively charged sites of the paper fiber by an ion exchange mechanism. The SDS adsorption isotherm was found to be the S-shaped. The addition of calcium did not have much effect on the adsorption of SDS. On the other hand, changing the pH had a considerable effect on the adsorption of SDS. The experimental results also revealed that the adsorption of SDS was better at low pH value. The differences in adsorption of SDS were clearly observed at concentrations before approaching the CMC
