Biosorption of Pb(II) ions from aqueous solutions by waste biomass of Streptomyces fradiae pretreated with NaOH

Abstract

Biosorption of Pb(II) ions from a model solution was investigated using Streptomyces fradiae biomass as biosorbent pretreated with sodium hydroxide. The mycelium is a waste product from the biotechnological production of the macrolide antibiotic tylosin in the pharmaceutical industry. The biosorption study was conducted in a batch system with respect to initial pH, initial metal concentration and contact time. For a description of the biosorption equilibrium, Langmuir and Freundlich adsorption models were used. Equilibrium data fitted better to the Langmuir model and the calculated maximum biosorption capacity was 138.88 mg·g−1 at initial pH 5.0, contact time of 120 min, biosorbent dose of 1 g·dm−3 and concentration range for the Pb(II) ions from 10 to 200 mg·dm−3. Pseudo-first and pseudo-second order kinetic models were applied to the experimental data. The results indicated that the Pb(II) uptake process followed the Ho equation. The interference of co-present ions Cu(II) and Zn(II) on the Pb(II) biosorption was also studied. It was determined that at the highest Pb(II) concentration (200 mg·dm−3) Cu(II) and Zn(II) caused 27.22% and 24.88% decreasing in Pb(II) uptake, respectively. The obtained results could be useful in prospective applications of chemically modified waste mycelium of S. fradiae as an alternative biosorbent for Pb(II) removal from aqueous solutions.