Biosorption of metals in brown seaweed biomass

Biosorption of Cd by biomass of the brown seaweeds Durvillaea, Laminaria Ec klonia and Homosira presaturated with Ca. Mg or K was coupled with the rele ase of these light ions. The feasibility of biomass pre-treatment to develo p a better biosorbent was evaluated by its biosorption performance, the deg ree of its component leaching (measured by the weight loss and TOC) as well as by the number of ion-exchange sites remaining in the biomass after the pre-treatment. Multicomponent Langmuir and ion exchange models applied to t he equilibrium sorption data for pH 4.5 confirmed the ion exchange mechanis m involved in the biosorption of metals. Both models fitted well the experi mental data and their parameters can be used in the derivation of dimension less ion-exchange isotherms which are instrumental in predicting the behavi or of the biosorbents in dynamic flow-through biosorption systems. The sequ ence of biomass affinities established for the selected heavy metals can be correlated with the chemical pretreatment of the biomass. (C) 1999 Elsevie r Science Ltd. All rights reserved.