Ana García-Rubio

Kinetics of the chemical reduction of nitrate by zero-valent iron

The use of reactive barriers is one of the preferred remediation technologies for the remediation of groundwater contamination. An adequate design of these barriers requires the understanding of the kinetics of the reaction between the target contaminant and the solid phase in the barrier. A study of the kinetics between metallic iron and aqueous nitrate is presented in this paper. Published literature regarding this reaction indicates that researchers are far from a consensus about the mechanism of this reaction. This paper presents the results obtained from experiments performed at different constant pH values and iron dosages, together with a mathematical analysis of the kinetic results. We have found that an Eley-Rideal kinetic model yields a good explanation of the relatively complicated dependence between rate of nitrate reduction and the pH value of the solution.

A Coupled Reactive-Transport Model for Electrokinetic Remediation

In this chapter, we present a model for the reactive-transport of chemical species through partially saturated porous media for electrokinetic remediation processes. A generalized theoretical model is presented, easily adaptable to specific remediation setups, target contaminants and supporting matrices; and we give detailed guidelines for the implementation of tailor-made numerical methods for the computer-aided solution. The model is subdivided into two coupled modules: one for reactive-transport, numerically solved by means of a non-linear finite element method; and another one for chemical equilibrium, solved using an enhanced Newton–Raphson method.

Feasibility Study of the Electrokinetic Remediation of a Mercury-Polluted Soil

This chapter is focused on the study of electroremediation of heavy metals from a real soil. Specifically, the case of the study was a soil from Almaden mining district, with a very high mercury concentration. The risk assessment of heavy metals depends on the mobility and bioavailability and not only on the total concentration. Therefore, this study evaluates the distribution of mercury into different fractions before and after the electrokinetic treatment.