Central Composite experimental design applied to removal of lead and nickel from sand.

The aim of this study was to apply Central Composite experimental design in the removal of lead and nickel ions from sand by electrokinetic remediation. Sand was used for an initial study since it is inert, thus making it possible to analyze the parameters influencing the process. Central Composite Design was used to create an experimental program to provide data to model the effects of various factors on removal efficiency. The variables chosen were ion concentration (C), applied potential (E) and time (t). The mathematical relationship between removal efficiency and three significant independent variables can be approximated by a second-order quadratic model. Response Surface Methodology (RSM) was used to describe the individual and interactive effects of three variables at five levels, combined according to a Central Composite Design. This study has shown that Central Composite Design can be applied to the removal of lead and nickel ions from sand, and it is an economical way of obtaining the maximum amount of information with the fewest experiments.