Electrochemical technique to measure Fe(II) and Fe(III) concentrations simultaneously

Abstract

An electrochemical technique is presented to simultaneously determine the concentrations of Fe(II) and Fe(III) ions using a rotating disk electrode. The method consists of using a steady state polarization technique where the developed limiting currents are measured and related to the concentration of the cations present in solution. Two linear equations were derived which correlate the limiting currents with the concentrations of the pair cations. The equations are used to easily and simultaneously determine the concentrations of the multivalent species. The precision and accuracy of the technique were found to be comparable to other advanced methods for the quantification of cations, such as capillary zone electrophoresis and spectro-photometric sequential injection analysis.

Occurrence and behaviour of dissolved, nano-particulate and micro-particulate iron in waste waters and treatment systems: New insights from electrochemical analysis

“…Electrochemical methods offer an interesting alternative because (a) they are rapid, (b) they can distinguish solid phase iron, dissolved Fe(II) and Fe(III), and (c) they can in principle be deployed to provide in situ, continuous monitoring. [7][8][9][10][11] Recently, Mudashiru et al 12 published a method showing how Cyclic-, Differential Pulse-and Steady-state Microdisc Voltammetry (CV, DPV, SMV) techniques can be combined to quantify total iron, colloidal iron and dissolved Fe(II) and Fe(III) in aqueous systems. Here, we combine these methods with mineralogical studies to unravel the occurrence and fate of dissolved, colloidal and particulate iron in a series of net-acidic (acidity > alkalinity) and net-alkaline coal mine drainages (alkalinity > acidity) and passive treatment systems.…”

Electrochemical Determination of the Concentration of Vanadium(IV) and Vanadium(V) Simultaneously

“…From a statistical standpoint, the absolute error is a more appropriate parameter to evaluate the accuracy of the technique. 26 It can been seen that the most of absolute errors are less than 2.5 mM. However, the increase of the relative and absolute error in the lower limits of the concentration for both V(IV) and V(V) species, could be explained due to instrumental limitations caused by background currents of the electrolyte solution which is associated with electrode-electrolyte interactions.…”

“…Electrochemical measurements.-The set up for the EM2C2 was described by Jin and Botte. 26 The technique is based in the measurement of the limiting current by using a RDE in a typical three-electrode cell. A Pt disk (0.2 cm 2 , from Pine Instrument, Purity 99.99%) imbedded in a rod of Teflon was used as working electrode.…”

“…A new approach was reported by Jin and Botte, the Electrochemical Measurement of Multivalent Cations Concentration technique, the method was used to measure Fe(II) and Fe(III) concentration in solution simultaneously. 26 The approach is based upon electrochemical properties of cationic solutions and the linear relationship between limiting current and cation concentration under diffusion limitations (Eq. 2):…”

“…Jin and Botte performed multiple hydrodynamic voltammetry studies until steady state was achieved. 26 Laminar flow can be achieved by controlling the rotation rate of the electrode, for that reason this technique requires the use of a rotating disk electrode (RDE). The range of angular velocity of the RDE in laminar flow conditions can be calculated using (Eq.…”