2.5. Effect of contact time and initial concentration
For the determination of the rate of metal biosorption by biomasses from 100 mL (at 10, 20, 50 and 100 mg/L) on a conical
250 mL flask, the supernatant was analyzed for residual metal at different time intervals. The pH and the adsorbent dosage
were kept constant at pH = 5± 0.01, which varied according to the adsorbent and adsorbate under consideration. Amount
of biomass dosage was 0.1 ± 0.001 g for biomass (Spirulina sp.) and temperature was 25 ±1 C and agitation speed of
the shaker was 120 rpm.