Dye Anionic Removal From Water by Green Synthesized Nannochloropsis Sp.- Cetyltrimethylammonium Bromide Surfactant: Kinetics, Adsorption Isotherm and Adsorbent Regeneration

Abstract

In this research, biomass modification of Nannochloropsis sp. with surfactant cetyltrimethylammonium bromide (CTAB) through a cation exchange reaction to produce adsorbent Nannochloropsis sp.-cetyltrimethylammonium bromide (AlgN-CTAB). Biomass modification of Nannochloropsis sp. by CTAB has been successfully carried out through confirmation from the analysis data produced by Fourier-transform infrared spectroscopy and scanning electron microscope & energy-dispersive X-ray spectroscopy. AlgN-CTAB adsorbent has been tested for its adsorption ability against anionic dye of methyl orange (MO) in solution by way of a sequence of experiments by the batch method. The optimum conditions for MO removal from the solution occurred at an adsorbent quantity of 0.1 g, pH of 5, and an interaction time of 60 min. MO adsorption kinetics data by AlgN and AlgN-CTAB tended to take the kinetics model of pseudo-second-order (PSO) with PSO rate constant (k2) values of 0.56 and 2.17 g mg-1min-1, serially. The MO adsorption isotherm pattern by AlgN tends to take the Freundlich adsorption isotherm whereas in AlgN-CTAB, it follows the Langmuir and Dubinin-Raduskevich adsorption isotherms (AIML and AIMDR). The results of the adsorption-desorption of MO by AlgN-CTAB with 4 repetition cycles resulted % removal of MO > 80%. The AlgN-CTAB adsorbent can be used repeatedly and is very effective in absorbing MO in solution.