To examine the heavy metal biosorption by the test organism,
stock solutions of Pb (II) and Cd (II) were prepared by
dissolving the nitrate salt of these metals in Milli-Q water.
The resulting stock solution was further diluted to obtain the
desired concentrations for biosorption experiments. For pH
adjustment, 0.1 N HCl and 0.1 N NaOH solutions were used.
All chemicals used in the present course of study were of
analytical reagent (AR) grade.
The solutions of metals were analyzed by using an atomic
absorption spectrophotometer (Varian AA 240 FS, Australia) at
a wavelength of 217 nm for lead and 228.8 nm for cadmium.
Infrared spectra of the samples were recorded on a Fourier
transform spectrophotometer (Nicolet 6700, Thermo Scientific,
USA). Spectrophotometric readings were taken by a doublebeam
UV–visible spectrophotometer (Shimadzu, 1601, Japan).