Equilibrium and Kinetic Studies of Cd2+ Biosorption by the Brown Algae Sargassum fusiforme

A fundamental investigation of the biosorption of Cd2+from aqueous solution by the edible seaweedSargassum fusiformewas performed under batch conditions. The influences of experimental parameters, such as the initial pH, sorption time,temperature, and initial Cd2+concentration, on Cd2+uptake byS. fusiformewere evaluated. The results indicated that thebiosorption of Cd2+depended on the initial Cd2+concentration, as well as the pH. The uptake of Cd2+could be described bythe Langmuir isotherm model, and both the Langmuir biosorption equilibrium constant and the maximum biosorptioncapacity of the monolayer decreased with increasing temperature, thereby confirming the exothermic character of thesorption process. The biosorption kinetics follows the pseudo-second-order kinetic model, and intraparticle diffusion is thesole rate-limiting step for the entire biosorption period. These fundamental equilibrium and kinetic results can supportfurther studies to the removal of cadmium fromS. fusiformeharvested from cadmium-polluted waters.