Removal of Lead and Cadmium Ions From Aqueous Solutions Using Dried Marine Green Macroalga (Caulerpa racemosa)

In this study Caulerpa racemosa has been characterized and used for the removal of Cd(II) and Pb (II) from aqueous solutions. The effect of pH, adsorbent dosage, contact time and temperature on adsorption process was studied in batch experiments. Langmuir and Freundlich models were applied to describe the biosorption isotherm of the metal ions by C. racemosa biomass. The adsorption data can be well described by Langmuir isotherm. The monolayer biosorption capacity of C. racemosa biomass for Pb(II) and Cd(II) ions was found to be 34.5 mg/g and 29 mg/g, respectively. Kinetics data of both metal ions were best described by pseudo second order model.The thermodynamic studies indicated that the adsorption was spontaneous and exothermic in nature. The analysis with FTIR indicated that possible functional groups involved in metal sorption by this alga were O–H bending, N–H stretching, C–N stretching, C–O and S=O stretching.