MATHEMATICAL EVALUATION OF THE EXPERIMENTAL AND MODELING ERRORS IN BIOSORPTION

The purpose of the presented work was to investigate the error in the experimental determination of metal. uptake during the batch equilibri um biosorption process. The objective was to quantify the inaccuracies in mass and volume measurement as well as calibration, drift and fluc tuation of the Atomic Absorption Spectrophotometer readings for an exa mple of Cd, Cu or Zn sorption by protonated Sargassum fluitans biomass . As a result, a mathematical description of the total error as a func tion of the initial and final metal concentrations, dilution factor, c alibration wavelength, solution volume, sorbent mass and sorbed specie s was developed. Dilution and insufficient difference between the init ial and final concentrations of the sorbed metal were determined to be the largest error sources. A recommendation for the choice of experim ental conditions such as the initial concentration and the correspondi ng solid to liquid ratio is made, so that excessive experimental error s can be avoided. The discrepancies between experimental data and pred ictions of a previously developed model for metal uptake in multi-meta l-systems were found to be of a similar magnitude as the estimated exp erimental error. Therefore, no significant modeling error could be det ected.