Kinetics and Isotherms of Mercury Biosorption by Dry Biomass of Arthrospira (Spirulina) platensis

Inorganic mercury was effectively removed from water solutions by means of dry biomass of Arthrospira (Spirulina) platensis as biosorbent. The results obtained at defined pH and biomass concentration as well as variable Hg concentrations were used to estimate biosorption kinetics and isotherm parameters. Biosorption kinetics was best described by the pseudo‐first‐order model of Lagergren that allowed estimating an average specific rate constant as high as 0.044 min−1, while the Dubinin and Radushkevich model was the best fitting isotherm. Hg biosorption seemed to occur via physisorption. Considering the wide dissemination of A. platensis and its easy cultivation, these results point to its biomass as a low‐cost biosorbent to treat Hg‐contaminated waters. Using dry Arthrospira platensis biomass as a biosorbent at different adsorption times and starting metal concentrations, inorganic mercury was successfully removed from water solutions. The results suggest that biomass of A. platensis, a cyanobacterium widespread throughout the world, may be employed as a cheap and efficient alternative biosorbent to remove mercury from wastewater.