Removal of basic dye (Astrazon Blue FGRL) using macroalga Caulerpa lentillifera

The macroalga Caulerpa lentillifera was found to have adsorption capacity for a basic dye, Astrazon Blue FGRL. For the whole range of concentrations employed in this work (20–1280 mg l−1), the adsorption reached equilibrium within the first hour. The kinetic data corresponded well with the pseudo second-order kinetic model where the rate constants decreased as initial dye concentrations increased. At low dye concentrations (20–80 mg l−1), an increase in the adsorbent dosage resulted in a higher removal percentage of the dye, but a lower amount of dye adsorbed per unit mass (q). The adsorption isotherm followed both the Langmuir and Freundlich models within the temperature range employed in this work (18–70 °C). The highest maximum adsorption capacity (qm) was obtained at 50 °C. The enthalpy of adsorption was estimated at 14.87 kJ mol−1 suggesting a chemical adsorption mechanism.