Screening of variable importance for optimizing electrodialytic remediation of heavy metals from polluted harbour sediments

Abstract

Using multivariate design and modelling, optimal conditions for electrodialytic remediation (EDR) of heavy metals were determined for

The influence of sediment properties and experimental variables on the efficiency of electrodialytic removal of metals from sediment

“…In all of the experiments a 3-compartment electrodialytic cell design was used and an illustration of the set-up can be found elsewhere [30]. The experimental set-up consisted of a centre compartment containing the sediment suspensions and electrolyte liquids were circulated in two adjoining compartments.…”

“…Metal partitioning, determined by sequential extraction, is an indication of how available the metals are in the sediment and to what extent a metal will be mobilised by ion-exchange, dissolution of carbonates, reducing or oxidising conditions, or acidic (pH<2) conditions. It can be a useful tool for assessing the potential for removing metals from sediments by electrodialysis and higher removal rates have for instance been observed for the more available metals (exchangeable/reducible) in the sediment [7,30].…”

“…Current density and time have been shown to be the most important experimental variables influencing EDR [16,25,[28][29][30]. High current densities may however impede the removal and increase the energy consumption significantly.…”

Applying multivariate analysis as decision tool for evaluating sediment-specific remediation strategies

“…Stirring has proven more efficient than a stationary set-up (Pedersen et al, 2003;Ottosen et al, 2012) and appears appropriate to apply for remediating dredged sediments. Other variables of importance to the efficiency of EDR include sediment, cell design, current density and time (Pedersen et al, 2015d;Pedersen et al, 2015e). The 2-compartment and 3-compartment cells used in the study were designed using the same materials and sizes; the 3-compartment cells consisted of two electrolyte compartment and between these a compartment containing the sediment suspension.…”

“…For this, different statistical tools may prove valuable and in a recent report the use of factorial design in optimizing the remediation of uranium polluted soils was reported (Radu et al, 2015). Another method is projections onto latent structures (PLS) which has been extensively used in chemical synthesis (Carlson and Carlson, 2005a) and also in studies of the influence of soil properties on PAH oxidation (Jonsson et al, 2007) and for identifying the most relevant variables for electrochemical treatment of sediments (Pedersen et al, 2015b;Pedersen et al, 2015c;Pedersen et al, 2015d).…”