Determination of Surface Parameters of Iron(III) Hydroxide Sorbent

Abstract

The surface layer parameters of iron(III) hydroxide were studied. The surface charge, the sorption of proton H+, hydroxyl OH– as a function of hydration time (TCT), the pH of the suspension solution and the sorbent concentration were presented. For this purpose, two methods were chosen: potentiometric mass titration (PMT) and potentiometric time titration (PTT). The concentrations suspensions used were 20, 40 and 60 g/L. The variations of surface charge with the time contact, Q = f(TCT) were examined for hydration time ranging from zero to 72 h. The isoelectric point (IEP) and point zero charge (PZC) were defined using the variations pH = f(TCT) resulting from protonation/deprotonating of surface sites >S–OH with derivative methods d(pH)/d(TCT) = f(pH) the values of PZC and IEP were found: PZC = 7.45 ± 0.1 and IEP = 7.65 ± 0.1.