The The amount of dye sorbed varied with initial
solution pH, dye concentration, seaweed dosage and temperature.
The amount of dye uptake decreased with increase in
temperature indicating that the dye biosorption is an exothermic
process. At 30 ◦C, a maximum uptake of 27 mg of dye per
gram of seaweed was exhibited by the Caulerpa species. The
sorption data were found to follow pseudo-second order kinetics.
Equilibrium data fitted well to Freundlich isotherm equation
confirming the heterogeneous sorption process of basic yellow
dye onto seaweed. The dye uptake process was found to be
controlled by external mass transfer at earlier stages and by
intraparticle diffusion at later stages. Boyd plot confirmed the
external mass transfer as the slowest step involved in the sorption
process. Thermodynamic parameters showed that the process is
exothermic and spontaneous. The results of this work indicate
that the green marine macroalga C. scalpelliformis constitutes a
promising material for the development of a lowcost biosorption
technology for the removal of dyes from effluents.