Biosorption of Cr3+, Cd2+ and Cu2+ ions by blue–green algae Spirulina sp.: kinetics, equilibrium and the mechanism of the process

Biosorption of Copper by Cyanobacterial Bloom-Derived Biomass Harvested from the Eutrophic Lake Dianchi in China

“…Four different desorbents were used to elute the adsorbed metal ion: 0.1 M of HCl, citric acid, HNO 3 , and disodium salt of ethylenediaminetetraacetic acid (EDTA) [8]. Washed copper-laden biomass was then suspended with 50 ml deionized water in dialytic tubes and put into beakers containing 450 ml of the desorbing agent.…”

“…The surface area of cells was measured using a method modified and adopted for measuring the surface area of microalgae [3].…”

“…However, 1.0 g dialytic biomass could remove 78% of the copper in the reaction solution; no more copper was removed with the increase of biomass. Compared with using cultured biomass of Spirulina maxima for copper removal [3], the harvested Microcystis biomass has a relatively low capacity for copper removing, but it shows a high efficiency of copper removal at low metal ion concentrations. The same phenomenon was also observed for cultured and immobilized biomass of Microcystis [12].…”

“…If a desorbent fulfills the requisite criteria, it is possible to recover metal ions in the form of concentrated solution and to regenerate the biosorbent for use in another biosorption cycle [3]. Four chemicals were used as desorbents for Cu 2?…”

“…One gram of bloom biomass was determined to have 2.26 m 2 of adsorptive surface area, higher than that of cultured Sprulina sp. [3]. However, because the surface area determined was very low, physical adsorption was assumed not to be the dominant mechanism of biosorption.…”