Voltammetric Determination of the Adsorption Kinetics of Acetic Acid on Activated Carbon

Abstract

The voltammetric behavior of acetic acid (HAc) at platinum electrode (2 mm in diameter) was investigated at the concentration range 5 mM to 95 mM. The cathodic peak around −0.55 V was attributed to the direct reduction of HAc molecules. The reduction current was linearly dependent on the initial concentration of HAc. Based on this linear relationship, voltammetry was proposed to be useful for analytical monitoring of HAc concentrations in a variety of systems. As an example application, voltammetric method was used successfully for determining the adsorption kinetics of HAc on activated carbon. The voltametric result qualitatively agreed with the titration measurement result. The adsorption data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The value of the pseudo-second-order adsorption rate constant was obtained to be 0.58 g mmol−1 min−1.