Removal of heavy metals by biosorption using freshwater alga Spirogyra hyalina.

ABSTRACT

The use of biosorbents for heavy metal removal has revealed enormous potential of algae for biosorption. The dried biomass of Spirogyra hyalina was used as biosorbent for removal of cadmium (Cd), mercury (Hg), lead (Pb), arsenic (As) and cobalt (Co) from aqueous solutions at different initial concentrations of the heavy metals and contact time of the biomass. The results showed that highest amount of Cd, Hg and As was adsorbed when the initial heavy metal concentration was 40 mg l-1 whereas Pb and Co exhibited greatest removal at 80 mg l-1. The value of Freundlich model constant (1/n) for different metals ranged from 0.342 to 0.693 and the values of Langmuir separation factor values (RL) varied between 0.114 and 0.719 that indicated favorable biosorption by the biomass. The order of metal uptake for the dried biomass was found to be Hg>Pb>Cd>As>Co. The finding of the study revealed that dried biomass of S. hyalina has much potential as a biosorbent for the sorption of Cd, Hg, Pb, As and Co.