Biosorption of malachite green from aqueous solution using brown marine macro algae Sargassum swartzii

Batch biosorption experiments were carried out for the removal of malachite green (MG) from its aqueous solution using raw Sargassum swartzii biomass (RSSB) as biosorbent. The effect of various operating parameters was optimized for enhancing biosorption capacity. The biosorption capacity was found to increase with contact time and initial malachite green concentration. The biosorption of the dye was pH dependent and maximum uptake was observed at a pH of 10. The experimental data were analyzed using Langmuir, Freundlich, and Temkin equilibrium isotherm models. Langmuir isotherm (R-2=0.98) was found to fit the experimental data well. The biosorption kinetics of MG was found to follow pseudo-second-order kinetic model (R-2=0.967). The mechanistic study revealed that the biosorption of malachite onto RSSB was controlled by film diffusion. The characteristics of the RSSB biosorbent were studied using Fourier transform-infrared spectroscopy and scanning electron microscopy.