Application of principal component analysis for the optimisation of lead(II) biosorption

Abstract

Current study was focused on optimising lead(II) biosorption carried out by living cells of Arthrospira platensis using Principal Component Analysis. Various experimental conditions were considered: initial metal concentration (50 and 100 mg/l), solution pH (4.0, 4.5, 5.0, 5.5) and contact time (10, 20, 30, 40, 50 and 60 min) at constant rotary speed 200 rpm. It was found that when the biomass was separated from experimental solutions by the filtration, almost 50% of initial metal dose was removed by the filter paper. Moreover, pH was the most important parameter influencing examined processes. The Principal Component Analysis indicated that the most optimum conditions for lead(II) biosorption were metal initial concentration 100 mg/l, pH 4.5 and time 60 min. According to the analysis of the first component it might be stated that the lead(II) uptake increases in time. In overall, it was found to be useful for analysing data obtained in biosorption experiments and eliminating insignificant experimental conditions. Experimental data fitted Langmuir and Dubinin-Radushkevich models indicating that physical and chemical absorption take place at the same time. Further studies are necessary to verify how sorption-desorption cycles affect A. platensis cells.

Keywords: Arthrospira platensis; Biosorption; Lead; Paper filter; Principal component analysis.

Fig. 1

PCA analysis of corrected q_corr (lead uptake) obtained at different times and initial lead concentrations (scores) under various pH conditions (loadings) for the first three components; circles indicate correlated loads and scores

Fig. 2

Langmuir isotherm of lead(II) sorption by living cells of A. platensis at different time intervals [pH = 4.5, lead(II) initial concentration = 100 mg/l, rotary speed = 200 rpm]

Fig. 3

Freundlich isotherm of lead(II) sorption by living cells of A. platensis at different time intervals [pH = 4.5, lead(II) initial concentration = 100 mg/l, rotary speed = 200 rpm]

Fig. 4

Dubinin–Raduskhevich of lead(II) sorption by living cells of A. platensis at different time intervals [pH = 4.5, lead(II) initial concentration = 100 mg/l, rotary speed = 200 rpm]

Fig. 5

Pseudo-first (a) and pseudo-second (b) kinetic models of lead(II) sorption by living cells of A. platensis at different time intervals [pH = 4.5, lead(II) initial concentration = 100 mg/l, rotary speed = 200 rpm]