Biosorption of Hg(II) and Cu(II) by biomass of dried Sargassum fusiforme in aquatic solution

The biosorption of heavy metals Hg(II) and Cu(II) from aquatic solution by biomass of dried Sargassum fusiforme was studied in the paper. The Sargassum fusiforme was able to absorb appreciable amount of mercury and copper from the aquatic solutions within 60 min of contact time with the metal solution and exhibited high removal of mercury and copper at low equilibrium concentrations. The specific adsorption of both Hg(II) and Cu(II) increased at low concentration of biomass and decreased when biomass concentration exceeded 2.0 g/L. The binding of mercury followed Freundlich model while copper supported Langmuir isotherm for adsorption with their r2 values of 0.971 and 0.923, respectively. The maximum adsorption per unit masses of Sargassum fusiforme (mg/L) at equilibrium (qmax) for Hg(II) and Cu(II) were calculated to be 30.86 and 7.69 mg/g, respectively. The biosorption by Sargassum fusiforme was best described using a pseudo-second-order kinetic model for copper and mercury ions in solution in the study. The adsorption was pH dependent as the maximum mercury biosorption and copper adsorption was happened at solution pH of 8–10.