Potential of sawdust as a green and economical sorbent for simultaneous preconcentration of trace amounts of cadmium, cobalt, and lead from water, biological, food, and herbal samples.

Abstract

Application of treated sawdust with NaOH as a green and economical sorbent for simultaneous preconcentration of trace amounts of Cd(II), Co(II), and Pb(II) ions from liver, lettuce, fish, and water as test samples with complicated matrices was investigated. Various parameters, such as effect of pH and contact time, breakthrough volume, type, and concentration of eluent and interference of ions were studied. The sorption was quantitative in the pH of 5.0 to 7.0 and desorption occurred instantaneously with 5.0mL of mixed solutions of ethanol and 2.0mol/L HNO3 -HCl and the amount of ions was measured by using flame atomic absorption spectrometry. Linearity was maintained at 3 to 500μg/L for cobalt, 5.0 to 800μg/L for lead, and 2.0 to 300μg/L for cadmium in the original solution. The relative standard deviation was less than 1.80% (n= 6, with concentration of 0.3mg/L for cadmium and 0.5mg/L for lead and cobalt). Detection limits and maximum capacity of the sorbent for Co (II), Cd (II), and Pb (II) in the original solution were 0.86, 0.50, and 1.7μg/L and 28.5, 30.6, and 47.3mg/g, respectively. The results for spiked real samples, effect of interfering ions, and adsorption capacity indicated that the applicability of this method for lead preconcentration is better than cadmium and cobalt preconcentration from complicated matrices. Practical Application: Sawdust can be applied as a green and economical sorbent for simultaneous preconcentration and solid-phase extraction of metal ions from food and environmental samples with complicated matrices.