Removal of heavy metals from aqueous solution by common freshwater filamentous algae

Abstract

Non-living (dried) biomass of five common filamentous algae belonging to Chlorophyta and Cyanophyta (Cyanobacteria) were screened for their metal ion sorption and removal efficiency in a batch system. A considerably higher magnitude of sorption of Pb 2+ and Cu 2+ by all the tested algae suggests the prevalence of Pb 2+ -and Cu 2+ -binding ligands in them. The Langmuir isotherm could more appropriately describe metal sorption by the test algae than the Freundlich isotherm. A 1 g l -1 biomass concentration of Pithophora odeogonia and Spirogyra neglecta, respectively removed 97 and 89% Pb 2+ in 30 min from a solution containing 5 mg l -1 initial concentration of Pb 2+ . Metal ion removal by the test algae decreased with increase in metal concentration in the solution. S. neglecta could remove >70% Pb 2+ even from a solution containing 75 mg Pb 2+ l -1 . S. neglecta and P. oedogonia could remove more than 75% of Pb 2+ and Cu 2+ from a multimetal solution, and therefore have tremendous potential for removing Pb 2+ and Cu 2+ from wastewaters containing several metal ions simultaneously. Other test algae, namely, Hydrodictyon reticulatum, Cladophora calliceima and Aulosira fertilissima were relatively less efficient in removing metal ions from solution.

Heavy metal uptake capacities by the common freshwater green alga Cladophora fracta

“…Deng et al (2006Deng et al ( , 2008 used nonliving Cladophora sp. to sorb copper (II), lead (II), and cadmium (II) and it has been assumed that dead cells could sorb more metals than living cells (Mehta and Gaur 2005;Singh et al 2007;Yu et al 1999). …”

“…Heavy metals cannot be biodegraded and thus will be accumulated in living tissues through transport and transformation, resulting in long-term potential adverse effects on water environment and human health (Deng et al 2008). Various undesirable toxic heavy metals such as mercury, cadmium, copper, zinc, lead, and nickel are well-known freshwater and marine pollutants (Mehta and Gaur 2005;Singh et al 2007;Travieso et al 1999;Yu et al 1999). Therefore, it is urgent to search for a suitable and easy way to efficiently solve this problem.…”

Metal sorption by algal biomass: From batch to continuous system

“…Microalgae adsorb great amounts of metal ions because they possess large surface area. Some freshwater filamentous green algae, such as, Spirogyra neglecta, Pithophora oedogonia, and Cladophora calliceima, have also shown good capacity for Cu(II) and Pb(II) sorption [116]. Dried biomass of Oedogonium sp.…”

Removal of Cu(II) and Pb(II) by Pithophora oedogonia: Sorption, desorption and repeated use of the biomass

“…Filamentous algae may be a good alternative for removing metal ions from aqueous system due to ease in their harvesting after metal sorption, good mechanical strength and easy availability. Unfortunately, literature on the use of filamentous algae in metal sorption is scant [15][16][17][18][19] and the subject indeed needs emphasis.…”