Packed-bed sorption of copper using spent animal bones: Factorial experimental design, desorption and column regeneration

A two-level factorial experimental design method has been proposed to investigate the influence of the operating parameters in a packed-bed adsorption column. This technique has been applied to quantify the influence of bed-depth, influent flow rate, and influent metal concentration on break-through time during the removal of copper from aqueous solutions using spent animal bones. A factorial model has been built-up and used to study all interactions among the considered parameters. It was found that while the effect of influent flow rate, as a main effect, was relatively insignificant, the effects of bed-depth and influent metal concentration were found to be significant at a 95% confidence interval. All other interactions between the studied parameters were significant. Desorption of copper from the bones-packed column was carried out using various concentrations of H₂SO₄. A solution of 50-mM was found to be suitable for this process. It has also been demonstrated that the efficiency of the bones-packed column did not change significantly after four sorption/desorption cycles.