METAL BIOSORPTION EQUILIBRIA IN A TERNARY-SYSTEM

Equilibrium metal uptake performance of a biosorbent prepared from Asc ophyllum nodosum seaweed biomass was studied using aqueous solutions c ontaining copper, cadmium, and zinc ions in binary and ternary mixture s. Triangular equilibrium diagrams can graphically represent all the t ernary equilibrium sorption data. Application of the multicomponent La ngmuir model to describe the three-metal system revealed its nonideal characteristics, whereby the value of apparent dissociation constants for the respective metals differed for each system. This restricted th e prediction of the ternary equilibria from the binary systems. Howeve r, some predictions of the ternary system behavior from the model were consistent with experimental data and with conclusions postulated fro m the three possible binary subsystems. (C) 1996 John Wiley & Sons, In c.