Production of a Spirulina sp. algae hybrid with a silica matrix as an effective adsorbent to absorb crystal violet and methylene blue in a solution

In this study, the adsorbent of Crystal Violet (CV) and Methylene Blue (MB) dyes was synthesized from the hybridization of Spirulina sp. algae biomass with silica as a matrix (ASS). Hybridization of Spirulina sp. algae biomass was carried out through a sol-gel process using tetraethyl orthosilicate precursors. The ASS adsorbent was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area method and scanning electron microscopy-energy-dispersive-X ray. The CV and MB dyes adsorption onto ASS adsorbent was studied through adsorption experiments using the batch method. The optimum adsorption of CV and MB dyes is at pH of 8 and contact time of 60 min. The CV and MB dye kinetics on the ASS adsorbent tend to follow the pseudo-second-order kinetics model with rate constant (k2) of 0.3 and 0.2 (g mg− 1 min− 1) respectively. The isotherm adsorption pattern of CV and MB dyes follows the Freundlich adsorption isotherm with KF values of 1.07 and 1.05 (mg g− 1) (L mg− 1)1/n, respectively. In the simultaneous adsorption process, CV dyes were more adsorbed than MB in solution to the ASS adsorbent.