A number of isotherm models were studied and modeled for colpomenia sinuosa. The experimental data were fitted among the 12 biosorption kinetic models. Thermodynamic studies indicated a spontaneous and endothermic process. The morphology of the biosorption process was revealed by Fourier transfer infrared (FT-IR) analysis and scanning electron microscope (SEM). The isotherm and kinetic parameters were compared with other microorganisms.