Iron(III) biosorption by Polyporus squamosus

Polyporus squamosus was tested for its ability to absorb Fe(III) ions from solutions. Kinetic and isotherm sorption experiments were conducted to evaluate the effects of contact time, pH, metal concentration, dose of the adsorbent, ionic strength and glucose. The increases in initial concentration of metal and pH of the solutions resulted in an increase in iron uptake. The equilibrium data could be fitted by Langmuir and Freundlich isotherm equation. Both Langmuir and Freundlich sorption models adequately describe the biosorption of Fe(III) by P. squamosus. Maximum metal uptake capacities of P. sqamosus biomass (qm) were found as 31.2, 18.1 and 12.2 mg/g for 1.5, 3.3 and 6.6 g biomass/l, respectively. With increasing ionic strength, there is a decrease in the metal uptake (qm) as well as coefficient b in Langmuir equation. It was noticed that lower concentrations of glucose resulted in higher rates and amounts of Fe(III) adsorption, while its concentration above 0.1% (w/v) reduced substantially the ability of the cells to absorb this metal.