Electrokinetic decontamination of heavy metals in construction materials: contribution of the different parameters to the global efficiency

Abstract

To discriminate between the relative weights of each factor involved in the global process of an electrokinetic treatment for remediation, mortar and brick contaminated with Cs, Sr, Co, Cd and Cu were submitted to electrokinetic treatments with different enhancing electrolytes (distilled water, Na2-EDTA, oxalic acid and citric acid), and the efficiency was analysed in function of the parameters involved in the process. The data obtained in this research, a matrix including 40 cases, have been correlated for the decontamination percentage in function of the key variables of the treatment, and the best correlation found, able to explain a variance of the 78.5% of the data, was a non linear exponential grow regression. An order in the weight of the contributions has been established that, from bigger to smaller contribution, is: constants of chelation equilibriums > precipitation as hydroxide constants > zeta potential > conductivity of the catholyte > pH catholyte > diffusion coefficient > pH of the material.